Phases of Menstrual Cycle:

The entire duration of a Menstrual cycle can be divided into four main phases:

Menstrual phase (From day 1 to 5):

It is also called bleeding phase. The corpus luteum produces progesterone. During 14 days of ovulation, progesterone makes the lining of the uterus thick for implantation and is necessary to sustain a healthy pregnancy. When the ovum is not fertilized, high level of progesterone inhibits secretion of luteinizing hormones (LH). This results in a decrease in the level of progesterone secreted by corpus luteum.

After 14 days of ovulation if the ovum is not fertilized the lining of the uterus starts degenerating and menstruation begins. The menstruation phase lasts for four to five days. The day when bleeding starts is considered to be the first day of menstrual cycle. The menstrual flow consists of the secretion of endometrial glands, cell debris (stripped off endometrium, mucus, leucocytes), blood and unfertilized ovum. During this phase, about 35 to 45 ml of blood is lost.

When the amount of progesterone further decreases the anterior pituitary is stimulated to secrete follicle stimulating hormone (FSH) and the follicular or proliferation starts. At the end of menstruation, the thickness of endometrium becomes 0.5 to 1 mm.

Failure of menstruation cycle indicates pregnancy. But it should be confirmed medically. Because sometimes the failure of menstruation may be due to poor physical and mental stress or poor health.

The level of estrogen, follicle stimulating hormone (FSH), progesterone and Luteinizing hormone (LH) are minimum. Actually level of FSH decreases slightly during this period.

Follicular or Proliferation Phase (From day 1 to 13):

This phase also begins on the first day of menstruation, but it lasts until the 13th day of the menstrual cycle. The following events occur during this phase:

The pituitary gland secretes a hormone that stimulates the egg cells in the ovaries to grow. One of these egg cells begins to mature in a sac-like-structure called the follicle. It takes 13 days for the egg cell to reach maturity. During this period the primary follicle in the ovary grows into the fully mature Graffian follicle. While the egg cell matures, its follicle secretes a hormone that stimulates the uterus to develop a lining of blood vessels and soft tissue called the endometrium.

The Graafian follicle also produces a hormone, estrogen, which stimulates the uterus to prepare itself to receive the ovum. Endometrium of uterine wall regenerates and ruptured blood vessels are repaired. The uterine glands grow. Thus it prepares the uterus for possible pregnancy. Hence follicular stage is also called proliferation state. By the end of this phase, the endometrium becomes 2 – 3 mm thick and endometrial glands become coiled and corkscrew shaped. The arterioles in uterine wall grow longer and branched making the wall highly vascular.

The level of estrogen starts increasing and it is maintained by follicle stimulating hormone (FSH) of the anterior pituitary. The level of FSH decreases initially but increases towards the ovulation. The level of progesterone remains almost constant. The level of Luteinizing hormone (LH) increases gradually.

Ovulation phase (Day 14):

On the 14th day of the cycle, the pituitary gland secretes a hormone that causes Graafian follicle to rupture and the ovary to release the matured egg cell. The released egg cell is swept into the fallopian tube by the cilia of the fimbriae. The cells of the ruptured Graafian follicle form the corpus luteum which secretes the hormone, progesterone.

Levels of estrogen, FSH and LH are at their peaks. The peak level of LH at the mid of cycle (14 th day) is called LH surge. Which makes the Graffian follicle to rupture and release the ovum (egg).

Luteal phase or Secretory Phase (From day 15 to 28):

The period after ovulation is called luteal phase. This phase begins on the 15th day and lasts until the end of the cycle. The egg cell released during the ovulation phase stays in the fallopian tube for 24 hours (up to day 15 or 16). If a sperm cell does not fertilize the egg cell within that time, the egg cell disintegrates.

After shedding the ovum, the remaining part of the Graffian follicle is called corpus luteum (Latin: yellow body). The corpus luteum produces progesterone. Progesterone makes the lining of the uterus thick for implantation and is necessary to sustain a healthy pregnancy. The production of progesterone continues till the placenta begins to take over progesterone production. The corpus luteum formed is active in this period hence this phase is called luteal phase. Due to a high level of progesterone in this phase, this phase is also referred as progesterone phase. At the same time, nutritious fluid is secreted during this period hence this phase is also known as the secretory phase.

If the ovum is not fertilized: The progesterone that causes the uterus to retain its endometrium gets used up by the end of the menstrual cycle. This causes the menstrual phase of the next cycle to begin. At the end of the 28th day, this ovum is rejected along with the uterine lining. The corpus luteum regenerates and gets converted into fibrous tissue called corpus albicans (Latin: white body). This marks the start of a slow disintegration of the thickened lining of the uterus and the next menstrual cycle 

If the ovum is fertilized: If the egg is fertilized, the corpus luteum starts receiving HCG(human chorionic gonadotropin) from the developing embryo. HCG instructs the corpus luteum to keep producing progesterone. Progesterone promotes further thickening of uterus up to 4 to 5 mm thick. endometrial glands become more coiled and more corkscrew shaped.  There is a secretion in the uterus from these glands which provides nourishment of dividing egg. The uterus is made ready for implantation. The higher progesterone inhibits further follicular maturation.

Irregular Menstrual Cycles:

When a girl begins menstruating, it may take some time for her periods to become regular. Most women have between 11 and 13 menstrual periods each year. Bleeding usually lasts around 5 days, but this too can vary, from 2 to 7 days. When menstruation first starts, it can take up to 2 years to establish a regular cycle (attaining the balance between estrogen and progesterone). However, for some female, the time between periods and the amount of bloodshed vary considerably. This irregularity is known as irregular menstruation.

The variation may be due to illness or mental tension such as stress or depression. The two hormones that impact menstruation are estrogen and progesterone.  Due to emotional condition the balance between them is not maintained. Extreme weight loss, extreme weight gain, endurance physical activity, eating disorders may be other causes of irregular menstruation. Before menopause, women often have irregular periods, and the amount of bloodshed may vary.

Hygiene During the Menstrual Cycle (Period):

• Daily bathing along with regular/daily washing of the genital area is essential. The vagina has its own cleaning mechanism which has a fine balance of good and bad bacteria. Use of soap can kill the good bacteria making way for infections. So use some warm water. Soap can be only used for external cleaning only and not the inner part.
• Sanitary pads and/or cloths used should be changed at least twice a day, if not more frequently.
• It is important to maintain menstrual hygiene in order to reduce the risk of contracting an infection of the female reproductive tract and urinary tract. To avoid infection the washing direction should be from the vagina to anus. opposite direction may cause infection.
• If pads or napkins are not changed frequently, the old blood begins to smell. This may lead to social embarrassment.
  Home-made sanitary napkins should be washed thoroughly with hot water and soap and should be dried in a sunny and airy place. They should be stored in a clean and dry place.
• When a female has periods, they should carry extra sanitary pads stored in a clean pouch or paper bag, a soft towel, some paper tissues or towels, hand sanitizer, a healthy snack, bottle of drinking water, a tube of antiseptic medication (if any).
• Moderate exercise and sufficient rest are also important.

Development of Follicle During Period:

Hormone Levels During Period:

Uterian Wall During Period:

Effect of Levels of Hormones:

Estrogen:

Estrogens can be produced by fat tissue, the liver, the adrenal glands and the ovaries. The ovaries are the primary source of estrogens in premenopausal women, except for women who are pregnant. If they are normal and balanced by progesterone produced by corpus luteum a woman feels well.

There is a condition called estrogen dominance where too much estrogen is circulating in relation to progesterone. In such conditions following symptoms are observed in females. Irregular or otherwise abnormal menstrual periods, Headaches (especially premenstrually), Mood swings (most often irritability and depression)

Lower estrogen results in less vaginal lubrication, increase in urinary tract infections, irregular or missing of periods, headaches, attack of preexisting migraines, depression, fatigue and trouble in concentration. The causes of low estrogen are excessive exercises, eating disorders, low functioning pituitary gland, etc.

Progesterone:

Progesterone is produced by corpus luteum in ovaries. It is responsible for making uterus ready for prospective pregnancy.

High level of progesterone results in weight fluctuations, drowsiness, depressed state ( not exactly depression),  dizziness, anxiety, feeling of tense, pain in legs. sleep inertia, etc.

Low level of progesterone results in headaches, migraines, mood changes, anxiety, depression, irregularity in periods.

Estrogen-Progesterone Balance:

Estrogen is balanced by progesterone. If it is not balanced estrogen may become the dominant hormone. This may lead to a variety of symptoms, including weight gain, mood swings, depression, heavy bleeding, irregular menstrual cycle, fibroids, gallbladder problems and thyroid dysfunction.

Menopause:

Menopause is the process through which a woman ceases to be fertile or menstruate. It is a normal part of life and is not a disease or a condition. It is a natural process in the body of any woman, but it causes drastic changes. A diagnosis of menopause is confirmed when a woman has not had a menstrual period for one year. The symptoms of approaching menopause are

• irregular periods: (periods may shorten or lengthen),
• Lower fertility: 3 to 5 years before menopause the estrogen level starts dropping. (Perimenopause stage). The lower level of estrogen decreases chances of pregnancy.
• Vaginal dryness: Due to the low level of estrogen vaginal lubrication decreases. Which results in vaginal dryness, itching, and vaginal atrophy.
• Hot flashes: These symptoms are shown in the first year of the final period. It is a sudden sensation of heat in the upper body. It may start in the face, neck, or chest, and progress upward or downward. It may make the skin red and patchy. The female start sweating, heart rate increases and irregular. These symptoms are mainly observed in the night during sleep cycles.
• Insomnia:  Sleeps may be disturbed due to anxiety.
• Urinary problems: There are possibilities of occurrence of urinary tract infections.
• Emotional changes: Depression, mood swings may be observed. that may lead to disturbed sleep.
• Low Concentration: short-term memory and difficulty in focusing.
• Physical Change:  Accumulation of fat in abdominal region resulting in obesity, hair loss, breast shrinkage.

Possible Effects of Menopause:

• Cardiovascular disease: (due to a decrease in estrogen)
• Osteoporosis: A decrease in bone density. Bones become brittle.
• Urinary incontinence: frequent, sudden, and overwhelming urges to urinate. Women may involuntarily urinate after coughing, sneeze, laughing, or lifting during menopause.
• Breast cancer:

The post Menstrual Cycle or Ovarian Cycle Or Female Reproductive Cycle appeared first on The Fact Factor.

Movements:

The act of changing position or place by one or more of its parts is called a movement. Movement is one of the significant features of living beings. Animals and plants exhibit a wide range of movements. The study of movements is called kinesiology (Greek: Kinein = to move and logos = to study).

Plants cannot move from one place to another as animal do. The growth of a plant is a movement. The closing of leaves of touch me not plant is a movement. Animals exhibit a wide range of movements. Streaming of protoplasm by forming pseudopodia in the unicellular organisms like Amoeba is a simple form of movement. Movement of cilia (as in paramoecium), flagella (as in bacteria) and tentacles (as in hydra) are shown by many organisms.

Advantages of Movements to Animals

• Movements of limbs or appendages help in locomotion. e.g. wings for flying, fins for swimming, legs for walking, etc.
• Movement of limbs and body parts for capturing, holding and ingestion of food. e.g. movements of tentacles, hands, jaws, tongue, etc.
• Movement of limbs, appendages and body trunk helps in adjusting body posture against gravity, for rest and relaxation.
• Movement of body parts for collecting information. Movement of eyeballs, external ears, antennae, tentacles.
• Movements also result in facial expressions and gestures.

Movements in the Human Body:

• The rhythmic beating of heart for circulation of blood
• Peristalsis in the alimentary canal to propel food forward.
• Movement of thoracic region (rib cage) and diaphragm for breathing

Movements at Different Levels:

• At the molecular level: The zigzag or Brownian movement of molecules in the cytosol (cytosol is the aqueous component of the cytoplasm of a cell, within which various organelles and particles are suspended). This movement is also called as a Brownian movement.
• At the cellular level: At this level, there is a movement of the cell itself. e.g. movement of amoeba by forming pseudopodia, movement of sperms (male gametes), movement of paramecium using cilia, movement of flagellated bacteria.
• At organ level: Movement of eyeballs, the beating of the heart, inflation and deflation of lungs during breathing, movement of tentacles, contraction, and relaxation of muscles, etc.
• At organism level: swimming of fishes in the water, flying of bird, running, walking are examples of organism-level movement.

Plants show molecular level, cellular level, and organ level movements. Animals show all the four types of movements. Organism level movement is a characteristic of animals.

Types of Movements:

Cells of the human body exhibit three main types of movements, namely, amoeboid, ciliary and muscular.

Amoeboid movements:

Amoeboid movement is shown by unicellular animals and cells which are amorphous i.e. not having definite morphology or shape. It is crawling movement by the formation of pseudopodia. Pseudopodia are formed by the streaming of protoplasm in the cell. Cytoskeletal elements like microfilaments are also involved in the amoeboid movement.

Example: Amoeba, macrophages, and leucocytes in blood exhibit amoeboid movement.

It is due to cytoplasmic flow. The cell forces the fluid inside it by pulling the cell forward forming false foot called pseudopodia.

To form the pseudopodia the cytoplasm within the cell undergoes a series of biochemical changes that alter the viscosity of the protoplasm within different areas of the cell. Due to some stimuli say that of food, the viscosity of protoplasm near the food end decreases and it almost becomes watery. In this condition, the protoplasm is referred to as plasma sol. While the viscosity of protoplasm at the far end increases and protoplasm becomes thick. In this condition, the protoplasm is called as plasma gel. This plasma gel acts as a wall and creates pressure on plasma sol. Under this excess pressure, the plasma sol has no choice but to move forward.

Ciliary Movements:

Ciliary movement occurs in most of our internal tubular organs which are lined by ciliated epithelium. The coordinated movements of cilia in the trachea help us in removing dust particles and some of the foreign substances inhaled along with the atmospheric air. Passage of ova through the female reproductive tract is also facilitated by the ciliary movement. Paramoecium moves in water using cilia.

Flagellar movement is similar to ciliary movement and can be seen in Euglena.

Muscular movements:

In vertebrates, locomotion depends on the bones or endoskeleton and muscles attached to them.  These muscles are called skeletal muscles. The bones and skeletal muscles together form musculoskeletal system. The movements of the body part are under voluntary control of the central nervous system. Therefore, skeletal muscles are also called voluntary muscles.

Locomotion

The voluntary movements which result in a change of place or location, then such movements are called locomotion. The movements associated with walking (as in man), running (as in horse, deer, cheetah), climbing (as in monkey), flying (as in birds, bats and insects), swimming (as in fish), hopping (as in rabbit, frog), creeping (as in earthworm), crawling (as in snake), gliding (as in flying lizard) results in locomotion.

There are animals like sponges, corals, some echinoderms and tunicates are fixed at one place to the substratum. The organisms which move from one place to another are called motile.

Paramoecium uses cilia for locomotion and as well as for the movement of the food through cytopharynx. Hydra uses is tentacles for capturing the food as well as for locomotion. We use limbs for locomotion and for doing many other functions like throwing, catching, holding, etc. Thus same organs or body parts are used for different purposes. Hence the movements and locomotion should be studied simultaneously.

All locomotions are movements but the converse is not true. The method and extent of locomotion in an animal depends on its habitat and demand of the situation.

There are animals that move on land (terrestrial), in the air (aerial), in trees (arboreal), and in the water (aquatic). Each of these environments requires a different type of movements for locomotion and each environment has its own pros and cons. Animals on the ground have to worry about friction, animals in the air have to worry about gravity, and animals underwater have to worry about buoyancy.

Most of the animals move in search of food, shelter, mate, suitable breeding grounds, favourable climatic conditions or to escape from enemies/predators.

Distinguishing Locomotion and Movement:

Locomotion involves the movement of the whole body from one place to another place. While movement includes the change in shape, size and direction of body parts with respect to the body axis. It may or may not involve a change of body position.

External body parts are involved in locomotion while external as well as internal body parts are involved in a movement.

All locomotions are movement but all movements are not locomotions.

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They have special properties like electric excitability, contractility, extensibility, and elasticity. Contractility is due to the presence of myofibrils formed by highly contractile proteins namely actin and myosin while the electrical excitability is due to the electrical potential difference across the plasma membrane of myofilaments.

Types of Muscles:

Muscles have been classified using different criteria, location, appearance and nature of regulation of their activities.

Skeletal Muscles or Striated Muscles:

Skeletal muscles occur in bundles and are closely associated with the skeletal components of the body. They have a striped appearance under the microscope and hence are called striated muscles. As their activities are under the voluntary control of the nervous system, they are also known as voluntary muscles.

The two ends of skeletal muscles are typically attached to two different bones by a tendon. The joint between the two bones act as a fulcrum and the contraction of the skeletal muscle bring the bone near to other. They are primarily involved in locomotory actions and changes of body postures.

Characteristics of Skeletal or Striated Muscles:

• They are found in limbs
• They are long and cylindrical
• They occur in a bundle
• They are multinucleate
• The sarcolemma is present in them
• Myofibrils are distinct and alternately light and dark striped. Hence called striated muscles.
• The intercalated (between the layer) disks are absent.
• They contract faster and get fatigued soon.
• They are voluntary.
• Innervated (connected with nerves) to the central nervous system.

Visceral Muscles or Smooth Muscles or Nonstriated Muscles:

Visceral muscles are located in the inner walls of hollow visceral organs of the body like the alimentary canal, reproductive tract, etc. They do not exhibit any striation and are smooth in appearance. Hence, they are called smooth muscles (nonstriated muscle).

Their activities are not under the control of the nervous system and are therefore known as involuntary muscles. They assist, for example, in the transportation of food through the digestive tract and gametes through the genital tract.

Characteristics of Visceral Muscles:

• They are found in the inner walls of hollow visceral organs of the body like the alimentary canal, reproductive tract, etc.
• They are long and spindle-shaped
• They form a sheet or tube or sphincter.
• They are uninucleate
• Sarcolemma is not present in them and they are bounded by a thin plasma membrane.
• Myofibrils are unstripped and indistinct. Hence called nonstriated muscles.
• The intercalated (between the layer) disks are absent.
• They contract slowly and do not get fatigued. Hence can remain contracted for a long time.
• They are involuntary.
• Innervated (connected with nerves) to the autonomous nervous system.

Cardiac Muscles:

Cardiac muscles are the muscles of the heart. They are striped muscles. Many cardiac muscle cells assemble in a branching pattern to form a cardiac muscle. They are involuntary in nature as the nervous system does not control their activities directly.

Characteristics of Cardiac Muscles:

• They are found in the heart
• They are short, cylindrical, and may be branched.
• They form a network
• They are uni or multinucleate
• The sarcolemma is present and is thin, bounded by a thin plasma membrane
• Myofibrils are distinct and alternately light and dark stripped.
• The intercalated (between the layer) disks are present.
• They contract quickly and never stop and never get fatigued.
• They are involuntary.
• Innervated (connected with nerves) to the autonomous nervous system.

Structure of Muscles:

Structure of Skeletal Muscle

The human body has nearly 639 to 650 skeletal muscles. Each organized skeletal muscle in the human body is made of a number of muscle bundles or muscle fascicles (plural: muscle fasciculi) held together by a common collagenous connective tissue layer called fascia or epimysium. Each muscle bundle contains a number of muscle fibres. Each muscle fascicle is covered by a connective tissue called perimysium.

Each muscle fibre or muscle cell is lined by the plasma membrane called sarcolemma enclosing the sarcoplasm. Muscle fibre is a syncitium as the sarcoplasm contains many nuclei. The cytoplasm containing many nuclei is called syncytial sarcoplasm. The nuclei are located on the periphery of sarcoplasm.

The interior of the sarcoplasm is occupied by the tubules of the endoplasmic reticulum or sarcoplasmic reticulum. It is the is the store house of calcium ions. A characteristic feature of the muscle fibre is the presence of a large number of parallelly arranged filaments in the sarcoplasm called myofilaments or myofibrils.

The cytoplasm contains glycogen granules and many mitochondria.

Structure of Miyofibril:

Each myofibril is about 1 – 3 μm in diameter. It has alternate dark and light bands on it throughout the length. Huxley, Murray, and Waber (1974) discovered that this striated appearance is due to the distribution pattern of two important contractile proteins Actin and Myosin. The light bands contain actin and are called I-bands or Isotropic bands or actin myofilament, whereas the dark bands called ‘A’ or Anisotropic bands or myosin myofilament contain myosin. Both the proteins are arranged as rod-like structures, parallel to each other and also to the longitudinal axis of the myofibrils.

In a resting state, the edges of thin filaments on either side of the thick filaments partially overlap
the free ends of the thick filaments leaving the central part of the thick filaments. This central part of thick filament, not overlapped by thin filaments is called the ‘H’ zone.

Light Bands or Isotropic Bands (I-bands)

• These bands are light coloured bands.
• These are formed of thin actin filaments only.
• They appear nonrefractive under polarized light and hence known as isotropic bands or I-bands.
• These bands are bisected by thin dark elastic fibre line at midpoint called z-line or z-band or Krause’s membrane.
• They are firmly attached to Z-discs.
• The part of a myofibril between two adjacent z-discs is called a sarcomere.
• These bands shorten during muscle contraction.

Dark Bands or Anisotropic Bands (A-bands)

• These bands are dark coloured bands.
• These are formed by thicker myosin and actin myofilaments.
• They are doubly refractive and hence known as anisotropic bands or A-bands.
• These bands are bisected by thin paler line at midpoint called Hensen’s line or H-zone. A narrow dark line passes through H-band and called as M-line or M-band or M- membrane.
• They are free at both ends.
• Length of these bands does not change during muscle contraction.

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Worldwide, typhoid fever affects roughly 17 million people annually, causing nearly 600,000 deaths. The disease is common in children of the age group 1-15 years. Approximately 3%-5% of patients become carriers of the bacteria after the acute illness. It is thought to have caused the deaths of many famous figures such as British author and poet Rudyard Kipling(the writer of The Jungle Book), the inventor of the airplane, Wilbur Wright, and the Greek Empire’s Alexander the Great.

Typhoid Mary:

It is a classic case in medicine.  Mary Mallon was born in 1869 in Ireland and emigrated to the US in 1884. She had worked in a variety of domestic positions for wealthy families prior to settling into her career as a cook. She was a healthy carrier of Salmonella typhi and spread typhoid for several years through the food she used to serve. Hence she was nicknamed “Typhoid Mary”.

Pathogen:

Typhoid is caused by acute infection of the intestine by rod-shaped bacteria Salmonella typhi. Originally it was isolated by Karl J. Erberth in 1880. It inhabits the lymphatic tissues of the small intestine, liver, spleen, and bloodstream of infected humans. It is most common in developing countries with poor sanitary systems and lack of antibiotics.

This gram-negative enteric bacillus belongs to the family  Enterobacteriaceae. It is a motile, facultative anaerobe that is susceptible to various antibiotics. Its pathogenicity is due to an outer membrane consisting largely of lipopolysaccharides (LPS). LPS protects the bacteria from the environment. The LPS is made up of an O-antigen, a polysaccharide core, and lipid A. The lipid A is made up of two phosphorylated glucosamines which are attached to fatty acids. These phosphate groups determine the toxicity of bacteria. Animals carry an enzyme that specifically removes these phosphate groups in an attempt to protect themselves from these pathogens. The O -antigen is on the outermost part of the LPS complex. This arrangement is responsible for the host immune response and makes it difficult for antibodies to recognize.

Up till now, 107 strains of this organism have been isolated.

Modes of Transmission:

Transmission takes place through faecal-oral route. People with acute illness can contaminate the surrounding water supply through stool, which contains a high concentration of the bacteria. Contamination of the water supply can, in turn, taint the food supply. The bacteria can survive for weeks in water or dried sewage. Houseflies are main vectors.

The infection is often passed on through contaminated food and drinking water, and it is more prevalent in places where handwashing is less frequent. It can also be passed on by carriers who do not know they carry the bacteria.

Incubation Period:

It is 1-3 weeks. After the ingestion of contaminated food or water, the Salmonella bacteria invade the small intestine and enter the bloodstream temporarily. The bacteria are carried by white blood cells in the liver, spleen, and bone marrow, where they multiply and reenter the bloodstream. People develop symptoms, including fever, at this point.

Bacteria invade the gallbladder, biliary system, and the lymphatic tissue of the bowel. Here, they multiply in high numbers. The bacteria pass into the intestinal tract and can be identified in stool samples.

The Course of Disease:

The course of untreated typhoid fever is divided into four individual stages, each lasting approximately for one week.

Symptoms:

• The two major symptoms of typhoid are fever and rash.
• Typhoid fever is particularly high, gradually increasing over several days up to 104 degrees Fahrenheit. Pulse rate is low. The rash consists of rose-colored spots, particularly on the neck and abdomen.
• Other symptoms can include Poor appetite, weakness, abdominal pain, constipation, headaches
• In some cases, the symptoms might include confusion, diarrhoea, and vomiting, but this is not normally severe.

Confirmation of Infection:

Presence of Salmonella typhi is confirmed by Widal Test.

Treatment:

• The only effective treatment for typhoid is antibiotics. The patient is treated with antibiotics such as Terramycin and Chloromycetin. The most commonly used are ciprofloxacin (for non-pregnant adults) and ceftriaxone. Continuous rehydration is required by drinking adequate water.
• Chloramphenicol was the original drug of choice for many years. Because of rare serious side effects, chloramphenicol has been replaced by other effective antibiotics. The choice of antibiotics is guided by identifying the geographic region where the infection was contracted.
• Those who become chronically ill (about 3%-5% of those infected), can be treated with prolonged antibiotics. Often, removal of the gallbladder, the site of chronic infection, will provide a cure.
• People who test positive as carriers may not be allowed to work with children or older people until medical tests show that they are clear.

Typhoid Antibiotic Resistance:

There is concern about the growing resistance of antibiotics to S. typhi. Typhoid has become resistant to trimethoprim-sulfamethoxazole and ampicillin. Ciprofloxacin is also experiencing similar difficulties.

Prevention:

Countries with less access to clean water and washing facilities typically have a higher number of typhoid cases.

Preventing Infecting Yourself (For Healthy Person):

• Wash hands frequently in hot, soapy water before eating or preparing food, as well as after using the toilet.
• Use alcohol-based sanitizer in the absence of hot water.
• Use boiled or bottled water for drinking.
• Eat foods that have been thoroughly cooked and served hot and avoid foods that have been stored or served at room temperature.
• Eat raw vegetables after peeling them.
• Avoid food and drink being sold by street vendors.

Preventing Infecting Others (For Recovering Patient):

• Follow the doctor’s instructions for taking antibiotics and be sure to complete the whole course.
• Avoid preparing food for others until it is confirmed that you are no longer contagious.
• Wash hands frequently using hot, soapy water before preparing or eating food, as well as after using the toilet.

Vaccination:

Vaccines are not 100 percent effective and caution should still be exercised when eating and drinking. Before traveling to a high-risk area, getting vaccinated against typhoid fever is recommended. This can be achieved by oral medication or a one-off injection (shot).

Live Typhoid Vaccine (Oral):

• It is a live, attenuated vaccine.
• Four doses: one capsule every other day for a week (day 1, day 3, day 5, and day 7). The last dose should be given at least 1 week before travel to allow the vaccine time to work.
• Swallow each dose about an hour before a meal with a cold or lukewarm drink. Do not chew the capsule.
• A booster dose is needed every 5 years for people who remain at risk.

Side Effects (Reaction):

• Fever or a headache (up to about 1 person in 20)
• Stomach pain, nausea, vomiting, rash (rare)

Who Should Not Take Vaccination?

Children younger than 6 years of age, anyone who has had a severe reaction to a previous dose of this vaccine, anyone who has a severe allergy to any component of this vaccine, anyone who is moderately or severely ill at the time the vaccine should not be administered with the vaccine.

Anyone whose immune system is weakened which includes anyone who has HIV/AIDS or another disease that affects the immune system has any kind of cancer and taking cancer treatment with radiation or drugs. should not be administered with vaccine directly. Oral typhoid vaccine should not be given until at least 3 days after taking antibiotics.

Inactivated Typhoid Vaccine (Shot)

One dose provides protection. It should be given at least 2 weeks before travel to allow the vaccine time to work.

A booster dose is needed every 2 years for people who remain at risk.

Side Effects (reaction):

Fever (up to about 1 person in 100)

A headache (up to about 1 person in 30)

Redness or swelling at the site of the injection (up to about 1 person in 15)

Who Should Not Take Vaccination?

Should not be given to children younger than 2 years of age, anyone who has had a severe reaction to a previous dose of this vaccine, anyone who has a severe allergy to any component of this vaccine and anyone who is moderately or severely ill at the time the shot.

Eliminating Typhoid:

Even when the symptoms of typhoid have passed, it is still possible to be carrying the bacteria. This makes it hard to eliminate the disease, because carriers whose symptoms have finished may be less careful when washing food or interacting with others.

The post Typhoid (Enteric Fever) appeared first on The Fact Factor.

Human Reproductive System:

Puberty means the changes that occur in boys and girls as they grow up. In this period the maturity of human sex organs begins. Most of these changes occur between the ages of 10 to 14 years. These changes are brought about by certain hormones. During puberty, the body grows rapidly, and both primary and secondary reproductive organs grow and become mature. Along with these changes, secondary sex characters also start appearing.

In males, primary sex organs are male gonads also known as testis. testis produce male gametes (male sex cells) also called sperms or spermatozoa.  In females, primary sex organs are the ovary. Ovary produces an ovum, plural: ova (female sex cells) also referred as eggs. The secondary sex organs are different in males and females. They include reproductive ducts for transporting gametes and accessory gland which help reproduction.

In males, sexual maturity is attained at the age of 13–14 years and in females, at the age of 11–13 years. Puberty ultimately leads to a stage when the child becomes an adolescent.  The World Health Organization (WHO) defines adolescence as the period from 10 to 19 years of age characterized by developments and changes in physical, psychological, and social areas.

During adolescence, the secondary sexual characters that develop are as follows:

• In males: deepening of the voice, widening of shoulders, muscular body, the appearance of beard and moustache, the growth of axillary and pubic hair, enlargement of external genital organs.
• In females: the growth of axillary and pubic hair, widening of pelvis and hip, enlargement of breasts (mammary glands) and initiation of the menstrual cycle.

The Stages of Human Reproduction:

Human shows sexual reproduction and the changes in the body takes place for viviparity. viviparity means the development of the embryo inside the body of the parent, eventually leading to live birth,

• Formation of gametes (Gametogenesis)
• Changes in the female body to facilitate the entry of sperms during copulation.
• The fusion of gametes. (Fertilization).
• Development of Zygote. (Embryology).
• Production of milk for the nourishment of young ones.
• Hormonal coordination by pituitary glands and gonads.

Human Fenmale Reproductive System:

The female reproductive system is divided into external and internal genitalia.

Female External Genitalia:

The ‘Vulva’ or the female external genital organs are those genital organs that are present on the surface of the female body and are also known as the female sexual organs.

Labia majora:

These are two large longitudinal folds (on the right and left side, of the vestibule) which form the boundary of the vulva and underlying fat extending backwards from the mons pubis. They are homologous to the scrotum in males. Posteriorly they merge into the perineum in front of the anus. It almost extends up to anus. Their outer surface becomes covered with hair at puberty. But the inner surface remains smooth, moistened with the secretions from the sebaceous (Sebaceous glands are microscopic exocrine glands in the skin that secrete an oily or waxy matter, called sebum) and other glands deep inside. The labia majora also contain apocrine glands (they are exocrine glands those produce sweat). They are composed of skin, fibrous tissue and fat. 

In a young girl, before the onset of menstruation, the labia majora are thinner with less fat and a fine smooth skin. Hair growth over the labia majora is one of the first signs of maturity of a young girl. In women in menopause, the labia majora becomes thinner with less fat and considerable hair loss.

Labia minora:

 These are smaller and thinner lip like folds located just next to the labia majora. The labia minora is also known as the inner labia, inner lips, or nymphae. They fold and protect the opening of the vagina, the urethra, and the clitoris. Labia minora forms a small projection at their upper end which is called prepuce. Labia minora are of different sizes in different women and the two labia minora may be of different sizes even in the same woman. If large in size, one or both labia may protrude from between the labia majora. Their inner surfaces remain in contact with each other. Posteriorly the labia minora are fused together to form fourchette. The labia minora contains no fat but are highly vascular that they become turgid during sexual stimulation. They are very sensitive to touch and pressure.

Labia are very thin and delicate, they can get torn during the labour or childbirth and may cause heavy bleeding and may continue up to six weeks from childbirth.

Mons Pubis (mons veneris):

The mons pubis is a fatty region that can be found directly above a woman’s pubic bone and above the labia majora. It comprises of coarse skin and pubic hair. It Provides a woman’s body, underlying bones, and tissues, natural physical protection during sexual intercourse.

Clitoris:

It is one of the most sensitive sexual organs of a woman’s anatomy. It is located in the external area at the anterior end of labia minora. and above the opening of the vagina. It is small erectile organ.  It is homologous to the penis of males. It shows the presence of erectile tissues.

It is solely designed to provide a woman with feelings of sexual pleasure and has no role in child conception.

Vestibule:

The vestibule is the part of the vulva lying between the two labia minora. It is a median vertical depression of vulva enclosing two important openings a) the external urethral opening which is a small slit-like opening just behind the clitoris and b) the vaginal opening which is a larger opening behind the urethral opening.

Hymen:

• The opening of the vagina is covered by a thin incomplete or partially occluding mucous membrane, called the ‘hymen’. In very rare cases it may be completely absent. In a condition known as the Imperforate hymen, the hymen forms a thick membrane completely covering the vaginal opening. It prevents the flow of blood and discharge during the periods and needs surgical treatment when a girl attains puberty. The hymen may break during sports or a heavy physical activity or during the initial act of sexual intercourse.

Vestibular Glands:

They are also called Bartholin’s glands. These are small pea-sized glands situated inside the vestibule on either side of the vaginal opening. These glands are homologous to the Cowper’s glands in the male. They secret lubricating fluid to lubricate the vagina and vulva. The duct from the gland to the vagina may sometimes get blocked, forming what is known as a Bartholin’s cyst. This cyst may need surgical treatment if it causes discomfort.

Breasts:

Anatomically they are known as mammary glands. These are a pair of rounded structures found in the pectoral region (chest region) on the ventral thoracic wall. They are present in both males and females. The structure of the male breast is nearly identical to that of the female breast, except that the male breast tissue lacks the specialized lobules, as there is no physiologic need for milk production by the male breast. They are well developed after puberty particularly in females. The breast does not contain muscles.

Each breast is a soft and rounded elevation. The skin over the centre of the elevation has a darkly pigmented circular area called the areola. There is a projection at the centre of areola called nipple which is erectile. These are modified sweat glands. Each breast contains fatty connective tissues and numerous lactiferous glands. It has 15 to 20 openings of lactiferous ducts which carry milk from mammary glands to nipples. Lactiferous glands dilate (become large) and form lactiferous sinuses just beneath the nipple to store the milk.  The release of milk from the breast is under the control of hormones prolactin and oxytocin secreted by pituitary glands.

During pregnancy, the ducts undergo a prominent change. They branch and the terminal part develops into proper alveoli. Towards the end of pregnancy, alveoli become distended and their cells start secreting milk. After lactation period the glandular tissue returns to the resting state.

It undergoes atrophy ( waste away due to the degeneration of cells) after menopause.

Skene’s Glands:

The Skene’s gland is also called the lesser vestibular, periurethral or paraurethral glands, or the correct name of the female prostate, and are located on the upper wall of the vagina and around the lower end near the urethral opening. The glands are made of the same cells as the male prostate and are what is thought to secrete the fluid ejected in female ejaculation.

Vestibular Bulbs:

the vestibular bulbs or clitoral bulbs are two elongated masses of erectile tissues situated on either side of the vaginal opening. They are more related to clitoris than the vestibule.

Perineum:

The perineum is the less hairy cutaneous area lying between the vaginal orifice in front and the anus behind.

Female Internal Genitalia:

Position of Internal Genitalia (Ventral View)

Position of Internal Genitalia (Lateral View)

Internal Genitalia (Front Sectional View)

Ovaries:

Ovaries are the primary sex organs of the female reproductive system. Ovaries are oval-shaped and almond-shaped glands, which lie in the lower part of the abdominal cavity on each side of a woman’s body. The Ovaries, which rest above a woman’s Fallopian Tubes. Each ovary is suspended from the dorsal body wall by a fold of peritoneum (the mesovarium). The ovary is connected to the uterus by an ovarian ligament and is connected to the lateral body wall by a suspensory ligament.

In both the males and females, the gonads develop within the mesonephric ridge and descend through the abdomen. However, unlike the testes, the ovaries stop in the pelvis.

Functions of Ovaries:

• The Ovaries store a woman’s eggs throughout her life cycle, from birth until menopause
• The Ovaries secrete female sex hormones, oestrogen, and progesterone. These two hormones control the menstrual cycle and secondary sexual characters. These hormones can also influence a woman’s mood, sex desire, energy, and additional  feelings/reactions
• The Ovaries produce an egg every month which is important for pregnancy.  The process of formation of egg in the ovary is known
  as oogenesis. 

Structure of Ovaries:

Surface: The surface layer of the ovary is formed by germinal epithelium consisting of a simple cuboidal epithelium. This lining is continuous with the mesothelium lining called peritoneum.

Cortex: The cortex is the outer part of the ovary. The cortex contains numerous spherical or oval sac like masses of cells known as ovarian follicles (Graffian follicles) and connective tissue called stroma. is largely comprised of a connective tissue stroma. It supports thousands of ovarian follicles. Each primordial follicle contains an oocyte surrounded by a single layer of follicular cells.Ovarian follicles are in various stages of development.

Medulla: The medulla (inner part) is composed of supporting stroma and contains a rich neurovascular network which enters the hilum of ovary from the mesovarium.

Ovarian Follicles:

The ovarian follicle carries a large centrally placed ovum, surrounded by several layers of follicular granulosa (granular cells)

Folliculogenesis:

Primordial Follicles: Primordial follicles are the initial reproductive units of the ovary that occur during the fetal development. They are present in very large number ( more than 2 million). At the birth of girl child, each ovary contains 1 million oogonia and 40000 remain by the time of puberty. Of these 400-450 of these primordial follicles reach maturity during the process of folliculogenesis. Remaining oogonia degenerate. The immature ovum or primary oocyte and surrounding follicular granulosa constitute the primordial follicle.

Primary Follicles: On attaining puberty, primordial follicles start to develop rapidly into primary follicles. During this transformation, the follicular cells convert into columnar cells and go through mitotic division to form multilayered granulosa cells. The sie oocyte in primary follicle is larger than that in primordial cells.

oocyte when compared to oocyte size in primordial follicles. on maturation, a uniform membrane called zona pellucida appears between the granulosa cells and oocyte.

Tertiary Follicles: Survived secondary follicle develops into tertiary follicle which is characterised by a fluid cavity called antrum (antral follicle). The oocyte lies at the edge of a mound made up of granulosa epithelial cells known as cumulus oophorous. oocyte grows in size and completes first meiotic division. The theca layer gets organised into two layers inner theca interna (well supplied with capillaries, from lipid-rich cells) and outer theca externa (contains larger vessels).

Graafian Follicle: The tertiary follicle further develops into the mature follicle called Graafian follicle. Graafian follicle ruptures and releases the secondary oocyte (ovum) from the ovary every menstrual cycle (alternatively from right and left ovary) by the process called ovulation.

Corpus Luteum: 

The ovum is shed from the ovary by the rupture of the Graffian follicle. This shedding of the ovum is called ovulation. Generally, it occurs14 days before the starting of the next menstrual cycle. After shedding primary oocyte divides and becomes the secondary oocyte. After shedding the ovum, the remaining part of the Graffian follicle is called corpus luteum (Latin: yellow body). The luteal phase is the second half of a woman’s menstrual cycle. The luteal phase begins after ovulation and continues until menstruation occurs.

The corpus luteum produces progesterone. Progesterone makes the lining of the uterus thick for implantation and is necessary to sustain a healthy pregnancy. The production of progesterone continues till the placenta begins to take over progesterone production.

Now there are two possibilities i.e. the egg (ovum) is not fertilized or egg is fertilized. Let us consider the first case when the egg is not fertilized. In this case, the corpus luteum dies and progesterone production stops. The corpus luteum regenerates and gets converted into fibrous tissue called corpus albicans (Latin: white body). When progesterone levels drop, the uterus lining stops thickening and is consequently shed during menstruation. If the egg is fertilized, the corpus luteum starts receiving HCG(human chorionic gonadotropin) from the developing embryo. HCG instructs the corpus luteum to keep producing progesterone. After ten weeks the placenta takes over progesterone production through the end of pregnancy. Hence corpus luteum lasts for maximum ten weeks.

If the corpus luteum does not produce enough progesterone (deficiency is called corpus luteum defect) to allow a pregnancy to develop then the lining of the uterus will begin to shed. The low progesterone levels in a pregnant woman may result in miscarriage.

Ovarian Cycle:

The series of changes that begins with the formation of the ovarian follicle and ends with degeneration of corpus luteum is called ovarian cycle.

Duct System:

It consists of two fallopian tubes, uterus, cervix and vagina.

Fallopian Tubes or Uterine Tubes (oviducts):

It is part of the female reproductive system which receives the egg (ovum) shed by the ovary during ovulation. It provides an appropriate environment for fertilization and transport of the egg to the uterus. It is a muscular tube about 10 cm long. Its lumen has a lining of ciliated epithelial cells. The opening of the fallopian tube is expanded into fimbriated funnel also called infundibulum that captures the ovum shed by the ovary. The infundibulum bears a number of finger-like processes at its free border called fimbriae. It shows the presence of an opening called ostium. The ciliated lining of lumen pushes the ovum towards the uterus.

For pregnancy to occur the fertilization should take place inside the fallopian tube. Ampula is the site of fertilization. To prepare for this potential occurrence of fertilization, the fallopian tubes have a healthy and nurturing lining. It facilitates the embryo to experience a safe voyage to the Uterus. Generally, embryos take several days to pass through the fallopian tubes into the Uterus but in some cases, it may take just a few hours.

Fallopian Tubes play a vital role in a woman’s reproductive abilities, hence any damage or tear to these tubes can cause infertility or conception difficulties.

Uterus (Womb):

It is a hollow muscular thick walled cavity approximately 7 cm in length, 5 cm wide and 2.5 cm thick. It is located at the midline of the pelvic cavity behind the urinary bladder and in front of the rectum. The wall of the uterus is made up of three layers the innermost endometrium, middle myometrium, and outermost perimetrium. The endometrium layer is richly supplied with blood vessels. Its innermost layer endometrium undergoes prominent cyclical changes the constitutes the menstrual cycle. Both the fallopian tubes open in the uterus. There is a sphincter muscle that closes the lower end of the uterus where it joins the vagina.

It is differentiated into a dome-shaped part above the opening of fallopian tubes called fundus. The broad upper part called body or corpus and narrow cylindrical part called cervix.

The uterus provides embryo with nurturing, safe, and nourishing environment. It is a temporary “home” for a developing fetus.

Potential Uterine problems that can negatively impact a woman’s ability to become pregnant typically include:

• Fibroid growths: They are non-cancerous growths leading to pain and bleeding
• Endometriosis:  The nourishing lining is formed outside of the Uterus instead of the inner side..
• Heavy menstruation patterns:  uncommonly heavy periods or frequent bleeding between periods
• Hormonal imbalances

Cervix:

The cervix is a cylinder-shaped neck of tissue that connects the vagina and uterus. Located at the lowermost portion of the uterus. It is composed primarily of fibromuscular tissue.  the Cervix remains shut during pregnancy, allowing a woman’s Uterus to support the developmental processes. During delivery of the child, the cervix will open several centimetres. This opening of the cervix is called “dilation”. As the cervix opens, a woman is able to push her baby out of the Uterus and down through the Vagina.

Vagina:

It is highly collapsible and highly distensible muscular passage 8 to 10 cm long. It connects uterus to the external world. It receives penis, the male reproductive organ and spermatozoa during copulation. It acts as a duct for the passage of uterine secretions and menstrual flow. It also acts as a path for the emergence of the baby into outside world during delivery.

It has three layers of tissue: mucosa, muscle, and fibrous tissue. The mucosa layer is the smooth surface layer. Below the mucosa, the fibro-elastic muscle tissues are present. They are used for tightening and widening of the vagina during sexual activities and childbirth (labour). The fibrous tissue of the third layer helps connect the vagina to other vital structures within a woman’s body.

Vaginal bacteria (Lactobacilli)  ferment the stored glycogen and makes the mucus acidic. Which prevents fungal infection.

Puberty in Female:

At puberty the internal reproductive organs reach maturity. The period is referred as menarche. It symbolises the beginning of the childbearing period.

The ovaries are simulated by the gonadotropins from the anterior pituitary and follicle stimulating hormone (FSH) and luteinising hormone (LH).

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Asexual Reproduction:

A mode of reproduction in which the offspring comes from a single organism, and not from the union of gametes as it is in sexual reproduction is called asexual reproduction

Characteristics of asexual reproduction:

• In this mode, an individual can give rise to daughter individuals by mitotic division of a part of its own body. As body cells are involved in the mitotic division. asexual reproduction is also termed as somatogenic reproduction.
• There is the absence of fusion of gametes. Hence asexual reproduction is also called agamogenesis or agamogeny.
• The offspring are genetically identical to the parent and dis exactly same without any variations. Hence the offspring is the clone of parents. Variations can take place only due to mutation.
• It is a faster method of multiplication.
• It may take place by binary fission, budding, vegetative propagation, spore formation (sporogenesis), Fragmentation (Regeneration), Parthenogenesis, apomixis and nucellar embryony.
• It is commonly observed in lower organisms like protists, sponges, coelenterates and certain flatworms.

Sexual Reproduction: 

Sexual reproduction is a mode of reproduction that involves fusion of female gamete (ovum) and male gamete (sperms) during fertilization.

Characteristics of sexual reproduction:

• In this method, two individuals are involved in the reproduction.
• There is a fusion of female gamete (ovum) and male gamete (sperms) during fertilization. The result of which zygote is formed, which develops into offspring.
• Due to the fusion of gametes, this mode of reproduction is also termed as gamogenesis or gamogeny.
• As characters of offspring are derived from two different individuals, variations can be observed.
• It is observed in higher organisms.

Human Reproductive System:

Puberty means the changes that occur in boys and girls as they grow up. In this period the maturity of human sex organs begins. Most of these changes occur between the ages of 10 to 14 years. These changes are brought about by certain hormones. During puberty, the body grows rapidly, and both primary and secondary reproductive organs grow and become mature. Along with these changes, secondary sex characters also start appearing.

In males, primary sex organs are male gonads also known as testis. testis produce male gametes (male sex cells) also called sperms or spermatozoa.  In females, primary sex organs are the ovary. Ovary produces an ovum, plural: ova (female sex cells) also referred as eggs. The secondary sex organs are different in males and females. They include reproductive ducts for transporting gametes and accessory gland which help reproduction.

In males, sexual maturity is attained at the age of 13–14 years and in females, at the age of 11–13 years. Puberty ultimately leads to a stage when the child becomes an adolescent.  The World Health Organization (WHO) defines adolescence as the period from 10 to 19 years of age characterized by developments and changes in physical, psychological, and social areas.

During adolescence, the secondary sexual characters that develop are as follows:

• In males: deepening of the voice, widening of shoulders, muscular body, the appearance of beard and moustache, the growth of axillary and pubic hair, enlargement of external genital organs.
• In females: the growth of axillary and pubic hair, widening of pelvis and hip, enlargement of breasts (mammary glands) and initiation of the menstrual cycle.

The Stages of Human Reproduction:

Human shows sexual reproduction and the changes in the body takes place for viviparity. viviparity means the development of the embryo inside the body of the parent, eventually leading to live birth,

• Formation of gametes (Gametogenesis)
• Changes in the female body to facilitate the entry of sperms during copulation.
• Fusion of gametes. (Fertilization).
• Development of Zygote. (Embryology).
• Production of milk for the nourishment of young ones.
• Hormonal coordination by pituitary glands and gonads.

Human Male Reproductive System:

The male reproductive system consists of parts for production of gametes and copulation.

The male reproductive system consists of a pair of testes, a pair of the epididymis, a pair of vasa deferentia (singular: vas deferens), urethra, penis and accessory glands. Teses are sex glands. vasa efferentia, epididymis, ductus deferens and ejaculatory ducts are part of the duct system. Seminal vesicles, prostate and Cowper’s gland form system of accessory glands. The penis is copulatory organ.

Testes:

They are the male gonads. During early foetal life, the testes develop in the lumbar region of the abdominal cavity just below the kidney. During the seventh month of development, then migrate into the scrotum permanently. Testes descend into the scrotum along with peritoneum, blood vessels and vas deferens. Failure of testes to descend from the abdomen into the scrotum leads to sterility called cryptorchidism.

Testes are extra-abdominal (present outside the abdomen) in a pouch made up of skin and connective tissue called scrotal sac or scrotum that hangs in the region between the legs. The walls of scrotum consist of smooth muscles called dartos tunic muscles. The scrotum is divided into two compartments by muscle septum. Each compartment encloses a testis, epididymis and a testicular end of a spermatic cord.

Scrotum protects the testes and acts as a thermoregulator. A scrotum has little or no fatty insulation hence it keeps the temperature of testes cooler than the body temperature. Thus scrotum helps in maintaining the temperature of testes at about 2-3°C lower than the body temperature. This temperature is suitable for the development of sperms. The temperature of the scrotum is maintained by involuntary muscles that connect the scrotum to the body. The contraction and relaxation of these involuntary muscles move the scrotum near or away from the body when the temperature of surroundings is low or high.

Note: In some seasonally breeding mammals the testes descend into the scrotum in the breeding season and ascends back in the abdomen in the non-breeding state.

Testes are soft, smooth, pinkish oval organs. In an adult male, each testis is approximately 4-5 cm long and about 12 g in weight. They are mesodermal in origin and located outside the abdomen scrotum. They are suspended in the scrotum by the spermatic cord. Each testis is connected to the wall of the scrotum by a short fibromuscular band called gubernaculum.

Histology of Testis:

The testis is externally covered by fibrous connective tissue called tunica albuginea. It is covered internally by tunica vascularis formed by capillaries and externally by an incomplete peritoneal covering called tunica vaginalis.

Transverse section of testis shows different stages of spermatogenesis like spermatogonia, primary and secondary spermatocytes, spermatids and sperms.

In each testis, there are 200 to 300 lobules. In each lobule, there are 1 to 4 convoluted loops called seminiferous tubules. Each tubule is 70-80 cm length when stretched out. the basement membrane of the seminiferous tubule is lined with highly specialized cells called spermatogonia. The spermatozoa occupy the central part of the lumen of the seminiferous tubule. The cells known as cells of Sertoli are also attached to the basement membrane. These cells provide mechanical support and protection to developing sperms and also participate in their nutrition and maturation.

In between seminiferous tubules masses of cells called interstitial cells or Leydig cells are present. These cells secrete the male hormone, testosterone, which is responsible for development and maintenance of male sex characteristics. The interstitial connective tissue also contains fibroblasts, blood vessels, nerves and lymphatics.

seminiferous tubules converge at the posterior surface and form a network of irregular tubules called rete testis.

Epididymis:

These are a pair of ‘C’ shaped structures each lying along the posterior border of each testis. It is a long (6 m) highly coiled tube which remains attached to the testis and lies within the scrotal sac. The long length of the epididymis delays the release of the sperm and allows them time to mature. Epididymis stores spermatozoa (sperms) and serves as a passage for their transport from the testis.

The epididymis consists of three parts: head (caput epididymis), body (corpus epididymis), and tail (cauda epididymis). The head of the epididymis is located on superior pole of the testis. It stores sperm for maturation. Here sperms acquire increased motility and fertilizing capacity. The tail stores sperms for short period before they enter vas deferens. The tail of the epididymis is continuous with the vas deferens.

Vas Deferens (Sperm Duct):

Each cauda epididymis continues as vas deferens. Each vas deferens is about 40 cm long and enters the abdominal cavity, passes
over the urinary bladder and joins the duct of seminal vesicle to form the ejaculatory duct.

Ejaculatory Duct:

These are the pair of ducts each about 2 cm long. It is formed by joining of vas deferens and a duct of the seminal vesicle. Both the ejaculatory ducts open into the urethra in the region of the prostate gland. They carry seminal fluid and spermatozoa to the urethra.

Urethra:

The urethra in males is about 15-20 cm long and is differentiated into three parts an anterior prostatic part which passes through the prostate gland; a middle membranous part; and a posterior penile part which passes through the copulatory organ, the penis. Urethra functions as a passage for both semen and urine.

The urethra is the tube that carries urine from the bladder to outside of the body. In males, it has the additional function of expelling (ejaculating) semen when the man reaches orgasm. When the penis is erect during sex, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm.

Penis:

The penis is a cylindrical, spongy, muscular, a highly vascular (supplied with blood vessels), erectile and pendulous copulatory organ in males. It is suspended in pubic region in front of the scrotum. The urethra runs through it centrally throughout its length. It contains three columns of erectile tissues.  Ordinarily, it remains small and limp. During sexual excitement, the spongy tissue gets filled-up with blood, making it erect, long and stiff.

Externally, the penis is covered by skin. Near the tip of penis, corpus spongiosum is enlarged making it soft and highly sensitive. It is called glans penis. It is covered by a loose fold of skin called prepuce or foreskin which can be retracted.

The penis contains two posterolateral tissues called corpora cavernosa and median corpus spongiosum. Urethra passes through spongiosum, hence it is called spongial urethra.

Accessory Sex Glands of Male Reproductive System:

Seminal Vescicles:

A pair of seminal vesicles is present at the base and posterior side of the urinary bladder. They are fibromuscular pouches. The seminal vesicles store sperms that descend from the testis and secrete seminal fluid. The seminal fluid is a viscous fluid and contains fructose, fibrinogen and prostaglandins. Fructose provides energy to sperms for swimming. The prostaglandins stimulate contraction in the female reproductive tract to help in the process of fertilization. The fibrinogen helps in coagulation of semen after ejaculation. Seminal fluid forms about 40-80 percent of the ejaculate (semen thrown out of the penis).

Prostate Gland:

Prostrate gland surrounds the first part of the urethra. It consists of 20 to 30 separate lobes which open separately into the urethra. It secretes an alkaline fluid which is discharged into the urethra. This fluid keeps the sperms alive and helps them to swim vigorously.

Due to its alkaline nature, it neutralizes the acidity of vaginal secretion and helps in maintaining the pH at 6.0 to 6.5. At this pH the sperms become motile and facilitate the process of fertilization. Secretion of prostate gland forms about 5-30 percent of the ejaculate.

Cowper’s Glands or Bulbo-Urethral Glands:

These are paired glands that lie below the prostate gland and join the urethra at a short distance from that of the prostate gland. They are pea-sized and situated on either side of the membranous urethra. Cowper’s glands secrete a white, viscous, alkaline secretion resembling mucus. It neutralizes acids that may be present in the penile urethra due to previous urination. It also lubricates vagina of the female genital tract.

Spermatozoa and Semen:

The semen is ejaculated during sexual intercourse called coitus. Semen is a whitish fluid containing spermatozoa and a mixture of secretions from seminal vesicles, prostate glands and Cowper’s gland. The process of expulsion of semen from the urethra is called ejaculation.

The process of formation of sperms or spermatozoa is termed Spermatogenesis. The spermatozoa are male gametes produced by the testes. Human sperm has three main parts head, neck and tail. The tip of a sperm is covered by
a cap-like structure, acrosome, which helps the sperm to penetrate inside the egg during fertilization.

In epididymis, spermatozoa are stored and they are non-motile. By the secretions from the accessory reproductive glands in males, they get activated and motile.

The sperms are released in millions. In one ejaculation  3 to 4 ml of semen is produced containing about 300,000,000 (3 × 10⁸) sperms are discharged but only one of the fertilizes the egg. The release of a large number of sperms ensures the process of fertilization.

Sperms when introduced into the vagina of the female move with the speed of 2 mm/minute inside the body of the female.

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In DNA replication, the double helix (parent strand) unzips forming two separate strands called templates. These templates provide the base sequences used to synthesize new DNA (daughter) strands. Replication is a very complicated enzyme-catalyzed process. Enzymes are needed to unwind the DNA prior to replication and repackage the DNA after synthesis. There are three hypothesis proposed for replication of DNA

Conservative replication:

In this process, the original helix serves as a template. The original molecule of DNA is preserved and entirely a new double-stranded molecule is synthesized.

Dispersive Replication:

In this hypothesis, it is proposed that the original molecule is broken into fragments. Each fragment serves as a template for the synthesis of complementary fragments and finally, two new molecules are formed which consist of both old and new fragments.

Semiconservative Replication:

This hypothesis was proposed by Watson and Crick on the basis of their model of DNA molecule. They proposed that the DNA molecule untwists and start separating at one end. 

During this process, the covalent hydrogen bonds between complementary bases are broken. The separated strands act as a template and using thesis template two new molecules of DNA are synthesized.

Experimental Evidence of Semiconservative Replication of DNA:

• In 1957, Matthew s. Meselson and Franklin W. Stahl confirmed semiconservative replication of DNA experimentally.
• They grew two cultures of E. coli in a medium using ammonium ions (NH₄⁺) as the source of nitrogen for DNA (as well as protein) synthesis.
• One culture was developed on a medium of (NH₄⁺) containing a light isotope (common) of nitrogen  ¹⁴N  and another culture was developed on a medium of (NH₄⁺) containing a heavy isotope (rare) of nitrogen ¹⁵N.
• After growing E. coli for several generations in a medium containing ¹⁵NH₄⁺, they found that the DNA of the cells was heavier than normal because of the ¹⁵N atoms in it.
• The difference could be detected by extracting DNA from the E. coli cells and spinning it in an ultracentrifuge. The density of the DNA determines where it accumulates in the tube.
• Then they transferred more living cells that had been growing in ¹⁵NH₄⁺ to a medium containing ordinary ammonium ions (¹⁴NH₄⁺) and allowed them to divide just once. The DNA in this new generation of cells was exactly intermediate in density between that of the previous generation and the normal. This could happen with either semi-conservative or dispersive replication. Thus the possibility of conservative replication was eliminated.
• This shows that half the nitrogen atoms in the new DNA are ¹⁴N and half are ¹⁵N. It tells us nothing about their arrangement in the molecules.
• However, when the bacteria were allowed to divide again in normal ammonium ions (¹⁴NH₄⁺), two distinct densities of DNA were formed: a) half the DNA was normal and b) half was intermediate.
• As this experiment was performed for next generations, the density of DNA molecule decreased continuously. i.e. lighter and lighter molecules of DNA are formed. It was continuous decrease and not a random change. This eliminates the possibility of dispersive replication.
• It is evident from the experiment that DNA molecules are not degraded and reformed from free nucleotides between cell divisions, but instead, each original strand remains intact as it builds a complementary strand from the nucleotides available to it.
• Each daughter DNA molecule is one-half “old” and one-half “new”. Hence this replication is called semiconservative replication. It shows that the DNA strand is immortal.  it will continue to serve as an unchanging template down through the generations.

Semiconservative Replication of DNA:

Activation of Nucleotides:

All the four types of DNA nucleotides are present in nucleoplasm in the form of their monophosphates. They are activated into triphosphates like dATP, dGTP, dTTP and dCTP using ATP in presence of enzyme called phosphorylase. This process is known as the activation of nucleotides.

dAMP   + ATP →    dATP  +  AMP              (Enzyme – Phosphorylase)

Origin or initiation Point:

DNA replication starts at certain specific sites situated on the molecule. Such sites are called origin points or initiation points. In eukaryotes, there are several origin points.

During replication, DNA molecules split (unzip) by activity of initiator proteins at the origin by forming an incision also called nick. Here the breaking of the hydrogen bond between two strands of DNA starts.

Unwinding of DNA Strand:

Enzyme DNA Helicase also called rep protein untwists the helix at locations called replication origins.

The replication origin forms a Y-shape and is called a replication fork. The replication fork moves down the DNA strand, usually from an internal location to the strand’s end. Thus every replication fork has a twin replication fork, moving in the opposite direction from that same internal location to the strand’s opposite end. Single-stranded binding proteins (SSB) also called helix destabilizing protein work with helicase to keep the parental DNA helix unwound. It works by coating the unwound strands with rigid subunits of SSB that keep the strands from snapping back together in a helix. The SSB subunits coat the single-strands of DNA in a way as not to cover the bases, allowing the DNA to remain available for base-pairing with the newly synthesized daughter strands.

Synthesis of New Strands:

Each separated strand acts as a template or mould for the synthesis of the complementary new strand. It takes place with the help of RNA molecule called RNA primer. The synthesis of RNA primer is controlled by an enzyme called RNA primase. RNA primer attracts complementary nucleotides from the surrounding nucleoplasm.

When the two parent strands of DNA are separated to begin replication, one strand is oriented in the 5′ to 3′ direction while the other strand is oriented in the 3′ to 5′ direction.

But DNA replication, is inflexible: the enzyme that carries out the replication, DNA polymerase, only functions in the 5′ to 3′ direction. This characteristic of DNA polymerase means that the daughter strands synthesize through two different methods, one adding nucleotides one by one (continuous)  in the direction of the replication fork, while the other adds nucleotides only in chunks (non-continuous). The first strand, which replicates nucleotides one by one is called the leading strand; the other strand, which replicates in chunks, is called the lagging strand.

The strand which opens from 3′ to 5′ is called leading template and its complementary strand is called leading strand. It is a continuous and fast process. Triggered by RNA primase, which adds the first nucleotide to the nascent chain, the DNA polymerase simply sits near the replication fork, moving as the fork does, adding nucleotides one after the other, preserving the proper anti-parallel orientation.

The strand which opens from 5′ to 3′ is called lagging template and its complementary strand is called lagging strand. DNA polymerase on the leading strand can simply follow the replication fork, because DNA polymerase must move in the 5′ to 3′ direction, on the lagging strand the enzyme must move away from the fork. But if the enzyme moves away from the fork, and the fork is uncovering new DNA that needs to be replicated. This was explained by Okazaki.

He proposed the formation of the lagging strand is discontinuous and takes place at a slower rate. the fragments of lagging strand formed during formation of complementary strands are called Okazaki fragments. These fragments are then joined by enzyme DNA ligase. Each Okazaki fragment requires an RNA primer. Later RNA primer is removed by the enzyme RNase.

Formation of Daughter DNA Molecules:

For each old strand, a new complementary strand is formed. Simultaneously the two strands undergo coiling and two identical DNA molecules are formed at the end of the process.

As new molecules formed in the replication process retain 50% from parent DNA molecule while remaining 50% is newly formed. Hence the replication is called semi-conservative replication.

Errors of DNA replication and its Repair:

There is a high degree of accuracy in DNA replication. Still, it may have an error of 1 in 1 billion base pairs formed. The initial rate of base pair error is high it is  1 error in 0.1 million base pairs.

But it is immediately corrected by repair enzymes (nucleases) within the DNA polymerase complex. This enzyme proofreads each base pair formed and then remove and replace the mistake in the base pair in coordination with enzyme ligase.

Note:

In Prokaryotes circular DNA is present. There is only one origin and the replication is called theta replication.

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Differences between RNA molecules and DNA molecule:

• RNA contains ribose sugar units while DNA contains deoxyribose sugar unit.
• RNA contains the base uracil while DNA contains thymine.
• RNA is single-stranded, except in some viruses while DNA is double-stranded structure.
• RNA molecules are much smaller than DNA molecules.
• RNA is mainly formed in the cytoplasm while DNA is mainly found in the nucleus.
• In RNA the ratio of nitrogen bases Purine to Pyrimidine may not be 1:1 but in DNA it is always 1:1.

RNA and its Classification:

RNA is a nucleic acid found in the nucleus as well as in the cytoplasm. They are further classified into a) genetic RNA and b) Non-genetic RNA. Genetic RNA acts as genetic material in the case of some viruses. Non-genetic RNA is responsible for protein synthesis.

RNA was the first genetic material. There is now enough evidence to suggest that essential life processes such as metabolism, translation, splicing, etc.), evolved around RNA. RNA used to act as a genetic material as well as a catalyst. RNA being a catalyst was reactive and hence unstable. Therefore, DNA has evolved from RNA with chemical modifications that make it more stable. DNA being double-stranded and having complementary strand further resists changes by evolving a process of repair

Structure of RNA:

Generally, RNA is a single-stranded structure. It may be simple and straight or folded or coiled upon itself. Chemically it is a polynucleotide molecule. Its components are ribose sugar, phosphate as phosphoric acid and nitrogen bases Purines and Pyrimidines. Purines are Adenine (A) and Guanine (G), while pyrimidines are Uracil (U) and Cytosine (C).

In RNA molecule nucleotides are joined by a phosphodiester linkage. RNA strand has 3′ and 5′ ends. The base pairing occurs in complementary bases only (A = U) and (G ≡ C). In RNA molecule the base pairing is not fixed and definite, hence the ratio of nitrogen bases purine to pyridine may not be 1:1

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Each cell in a particular living organism contains the exact same DNA. The size of the DNA polymer is directly related to the complexity of the organism; more complex organisms tend to have larger molecules of DNA, while less complex organisms have smaller DNA.   For e.g. The DNA in simple bacteria contains about 8 million nucleotides, whereas human DNA contains up to 500 million nucleotides.

Primary Structure:

The primary structure of DNA is simply the sequence of nucleotides. The sugar-phosphate chain is called the DNA backbone, and it is constant throughout the entire DNA molecule. The variable portion of DNA is the sequence of nitrogenous bases. 

The phosphate groups link the 3rd carbon of one sugar (of deoxyribose or ribose) to the 5th carbon of the next sugar (of deoxyribose or ribose).

A strand of DNA has two distinct terminals or ends, one will be a 5-phosphate end and the other will be a 3-hydroxyl end. By convention, a nucleic acid sequence is always read in the 5 to 3 direction, that is, from the sugar with the free 5-phosphate to the sugar with a 3-hydroxyl group. The order of nucleotides is generally written using the capitalized first letter of the name of a base. Thus the following structure is written ACGT (in the 5 to 3 direction)

Secondary Structure (Double Helix Structure):

Double Helix Structure:

The secondary structure of DNA was proposed by James Watson and Francis Crick in 1953. This was considered to be the greatest discovery of modern biology and hence they got Nobel prize for the same. They proposed that DNA is a double helix containing two polynucleotide strands wound as if around a central axis.

Complementary Base Pairing:

The two polynucleotide strands are connected by hydrogen bonds formed between a purine on one strand and a pyrimidine on the other. In DNA, adenine is always paired with thymine and guanine is always paired with cytosine. The pairs A-T and G-C are called complementary base pairs. According to base-pairing rules discovered by Watson and Crick, each A is bound to T and each G is bound to C.

Purine Pyrimidine Ratio:

Therefore, the total number of A’s in any molecule of DNA must be equal to a total number of T’s (the same is true of G and C). Thus, the % of A in DNA must equal the % of T (the same is true of G and C). The total percent of A, T, G, and C must be equal to 100. Human DNA contains 30% adenine, 30% thymine, 20% cytosine, and 20% guanine.

Due to complementary base pairing, the total number of purine bases is equal to a total number of pyrimidine bases. Thus the ratio is 1:1. This relation is called Chargaff’s rule.

The Polarity of Strands (Antiparallel):

The two strands of DNA run antiparallel to one another, that is, the two strands run in opposite directions. One in the 5 to 3 direction, the other in the 3 to 5 direction. Therefore, both ends of the double helix contain the 5 end of one strand (5 phosphate) and the 3 end of the other (3 OH).

Major and Minor Grooves:

The helix is right-handed and it results in the formation of a deep groove called a major groove and another shallow groove called a minor groove. The two groves are alternate.

Dimensions:

The diameter of the DNA molecule is 2 nm. The deflection pitch angle of a helix is 36º. The helix completes its one turn after covering a distance of 3.4 nm. There are 10 base pairs in one complete spiral.

Packaging of DNA:

The length of a DNA double helix molecule in a typical mammalian cell is approximately 2.2 metres.  This length can be obtained by multiplying the total number of base pairs present in the DNA double helix, which is 6.6 X 10⁹, with the distance between two consecutive base pairs, which is 0.34 × 10^-9 m. Such a long polymer is packaged within a typical nucleus of size 10 -6 m, by condensing it by coiling and supercoiling (coiled-coil) to fit in the nucleus. which is different for both prokaryotes and eukaryotes.

In prokaryotes, the negatively charged DNA is arranged in large loops and is held together by a few positively-charged proteins, called the nucleoid. In eukaryotes, a single molecule of negatively charged DNA is packaged around a pool of positively charged proteins called histones.

Histones are proteins that are rich in basic amino acid residues lysines and arginines. They carry a positive charge on their outer side chain. There are four types of histones H2A, H2B, H3 and H4. Two types of each, thus four molecules of histones form an octamer. The negatively charged DNA is wrapped around the positively charged histone octamer to form a nucleosome. It is held in place by the H1 histone.

A typical nucleosome has around two hundred (146 + 54) base pairs of DNA helix and it is the nucleosomes that make up the repeating unit in chromatin.

Under an electron microscope, the nucleus shows a chromatin network. In the network, nucleosome can be seen as beads on the string.  1 and 3/4th turn around histone octamer consist of 146 base pairs and is called core DNA. Adjacent DNA acts as a linking strand consists of 54 base pairs and is called linker DNA. H1 histone is present in the linker region and as DNA makes two complete turns it is present where DNA starts wrapping the histone and leaves it.

The thin and long nucleosome fibre is coiled again to form a supercoiled structure to make solenoid fibre with diameter 30nm or 300 A°. Nucleosome and solenoid fibres are characteristic of the nucleus at interphase. For further packing of chromatin additional protein Non-Histone Chromosomal (NHC) proteins are responsible. The chromatin fibres are of two types, euchromatin and heterochromatin.

The euchromatin fibres are of thirty to eighty nanometres in diameter and are loosely packed and stain light. While heterochromatin fibres are of about three hundred nanometres in diameter and are more densely packed and stain dark. The euchromatin is transcriptionally active, while heterochromatin is inactive.

These chromatin fibres coil further and condense to form short and thick bodies called chromosomes, which are further packaged within the nucleus.

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Human blood is classified into 4 main groups: A, B, AB and O. Each can be either Rhesus + ve or Rhesus – ve, giving 8 groups in all. Blood grouping is the identification of the antigens in a blood sample. This system is called the ABO system.

The ABO system is based on the A and B antigens. It classifies blood by the antigens on the surface of the RBCs and the antibodies circulating in the plasma. An individual RBC may carry an ‘A’ antigen, a ‘B’ antigen, both ‘A’ and ‘B’ antigens, or no antigen at all. These antigen patterns are called blood types A, B, AB, and O, respectively.

Genetic Basis of Blood Groups:

• The gene I control ABO blood groups it has three alleles; IA , IB and i.
• The allele IA and IB produce slightly different types of sugar and allele i does not produce any sugar.
• As humans are diploid organisms each person possesses any two of the three  I genes.
• IA and IB are co-dominant and completely dominant on i.

Blood Group of Children:

Donating Blood by Compatible Type:

Blood types are very important when a blood transfusion is necessary. In a blood transfusion, a patient must receive a blood type compatible with his or her own blood type. If the blood types are not compatible, red blood cells will clump together, making clots that can block blood vessels and cause death.  Therefore, it is important that blood types be matched before blood transfusions take place. In an emergency, type O blood can be given because it is most likely to be accepted by all blood types. However, there is still risk involved.

Type AB is known as a universal recipient, meaning that they can receive any type of blood, while O is the universal donor, meaning they can donate blood to anyone. The universal red cell donor has Type O negative blood type. The universal plasma donor has Type AB positive blood type.

Rhesus System:

An antigen that is sometimes on the surface of RBC is the Rh factor named after the Rhesus monkey in which it was first discovered. If this factor is present then the blood is Rh + ve, and if it is absent the blood is Rh – ve.

If an Rh – ve person receives a transfusion of blood that has Rh + ve antigens, anti-Rh + ve antibodies will be formed and will react with the Rh + ve antigen and agglutination (clumping i.e. The antibody or other molecule binds multiple particles and joins them, creating a large complex) will occur.

Seriousness of Rhesus System:

The most serious problem with Rh incompatibility occurs during pregnancy. If the mother is Rh – and the father is Rh+, the child may inherit the dominant Rh+ allele (gene) from the father. The baby’s Rh+ blood will then get into the mother’s blood during delivery, causing her to develop antibodies to the Rh factor.

If a second Rh+ child is later conceived, the mother’s antibodies will cross the placenta and attack the blood of the foetus, causing a condition known as rhesus baby syndrome. The symptoms include damaged liver and so fewer RBCs, less developed brain (due to lack of oxygen) and skin.

To prevent this, any Rh mother will automatically be given an injection of anti-Rh+ antibodies (known, confusingly, as anti-D) at childbirth. These antibodies attack and destroy all Rh+ antigens in the mother’s blood, thus preventing her from becoming sensitized to the Rh+ antigen.

This tricks her body into believing she has not had an Rh +ve child, and so the next pregnancy will be protected from attack since she will have no antibodies to Rh +ve blood

Health Benefits Of Donating Blood

Blood donation is a voluntary procedure. You agree to have blood drawn so that it can be given to someone who needs a blood transfusion. Millions of people need blood transfusions each year. Some may need blood during surgery.

Hemochromatosis

It reduces the risk of hemochromatosis. Hemochromatosis is a health condition that arises due to excess absorption of iron by the body. This may be inherited or may be caused due to alcoholism, anemia or other disorders. Regular blood donation may help in reducing iron overload.

Anti-cancer benefits

Blood donation may also help in lowering the risk of cancer. By donating blood the iron stores in the body are maintained at healthy levels. And the reduction in iron levels in the body is linked with low cancer risk.

Healthy heart and liver

Blood donation is beneficial in reducing the risk of heart and liver ailments caused by iron overload in the body. Intake of iron-rich diet may increase the iron levels in the body and since only limited proportions can be absorbed excess iron gets stored in the heart, liver, and pancreas. This, in turn, increases the risk of cirrhosis, liver failure, damage to the pancreas, and heart abnormalities like irregular heart rhythms. Blood donation helps in maintaining iron levels and reduces the risk of various health ailments.

Weight Loss:

Regular blood donation reduces the weight of the donors. This is helpful to those who are obese and are at higher risk of cardiovascular diseases and other health disorders. However, blood donation should not be very frequent and you may consult your doctor before donating blood to avoid any health issues.

New Blood Cells

After donating blood, the body works to replenish the blood loss. This stimulates the production of new blood cells and in turn, helps in maintaining good health.

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