Spermatogenesis is the process in which spermatozoa are produced from spermatogonial stem cells by way of mitosis and meiosis. The initial cells in this pathway are called spermatogonia, which yield primary spermatocytes by mitosis.

The heart is the body's engine room, responsible for pumping life-sustaining blood via a 60,000-mile-long (97,000-kilometer-long) network of vessels. The organ works ceaselessly, beating 100,000 times a day, 40 million times a year—in total clocking up three billion heartbeats over an average lifetime. It keeps the body freshly supplied with oxygen and nutrients, while clearing away harmful waste matter.

Colonoscopy is a test that allows your doctor to look at the inner lining of your large intestine (rectum and colon). He or she uses a thin, flexible tube called a colonoscope to look at the colon. A colonoscopy helps find ulcers, colon polyps, tumors, and areas of inflammation or bleeding.

The deep veins play a significant role in propelling blood toward the heart. The one-way valves in deep veins prevent blood from flowing backward, and the muscles surrounding the deep veins compress them, helping force the blood toward the heart, just as squeezing a toothpaste tube ejects toothpaste.

Endometriosis (en-doe-me-tree-O-sis) is an often painful disorder in which tissue that normally lines the inside of your uterus — the endometrium — grows outside your uterus. Endometriosis most commonly involves your ovaries, fallopian tubes and the tissue lining your pelvis. Rarely, endometrial tissue may spread beyond pelvic organs.

Bone tumors develop when cells in the bone divide without control, forming a mass of tissue. Most bone tumors are benign, which means they are not cancer and cannot spread. However, they may still weaken bone and lead to fractures or cause other problems. Bone cancer destroys normal bone tissue and may spread to other parts of the body (called metastasis). Benign Bone Tumors Benign tumors are more common than malignant tumors of the bones. These are a few common types of benign bone tumors: Osteochondroma is the most common benign bone tumor. It is more common in people under age 20. Giant cell tumor is a benign tumor, typically affecting the leg (malignant types of this tumor are uncommon). Osteoid osteoma is a bone tumor, often occurring in long bones, that occurs commonly in the early 20s. Osteoblastoma is a single tumor that occurs in the spine and long bones, mostly in young adults. Enchondroma usually appears in bones of the hand and feet. It often has no symptoms. It is the most common type of hand tumor.

They were victims of caisson disease. This condition, also known as the bends or decompression sickness, is caused by the formation of gas bubbles in the body. Human body tissues contain small amounts of the gases present in the air.

Lysosomal storage diseases (LSDs; /ˌlaɪsəˈsoʊməl/) are a group of approximately 50 rare inherited metabolic disorders that result from defects in lysosomal function. Lysosomes are sacs of enzymes within cells that digest large molecules and pass the fragments on to other parts of the cell for recycling.

Signs and symptoms of this condition typically appear around the age of 3 or 4 months, when babies start to sleep through the night and do not eat as frequently as newborns. Affected infants may have low blood sugar (hypoglycemia), which can lead to seizures. They can also have a buildup of lactic acid in the body (lactic acidosis), high blood levels of a waste product called uric acid (hyperuricemia), and excess amounts of fats in the blood (hyperlipidemia). As they get older, children with GSDI have thin arms and legs and short stature. An enlarged liver may give the appearance of a protruding abdomen. The kidneys may also be enlarged. Affected individuals may also have diarrhea and deposits of cholesterol in the skin (xanthomas).

This Unorthodox Procedure Makes Short People A Foot Taller

For both DCIS and invasive cancer, radiation therapy to the remaining breast tissue is generally recommended after surgery. A lumpectomy may also be called breast-conserving surgery, a partial mastectomy, quadrantectomy, or a segmental mastectomy. A mastectomy is the surgical removal of the entire breast.

A nephron (from Greek νεφρός (nephros) meaning "kidney") is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.

Lithium, a mood stabilizer used in bipolar disorder, has a narrow therapeutic index (small difference between therapeutic and toxic levels}. This patient's gradual onset of neurologic symptoms (slurred speech, confusion, tremors, and ataxia) is consistent with chronic lithium toxicity. Therapeutic lithium levels are 0.8- 1.2 mEq/L. Serum lithium levels >1.5 mEq/L confirm toxicity, and levels ;::2 .5 mEq/L require emergency management.

Thumb Tip Regeneration! IV3000 Wound Dressing for Thumb / Finger Trauma

Miracle baby's heart beats outside her chest

The "great arteries" in this anomaly refer to the aorta and the pulmonary artery, the two major arteries carrying blood away from the heart. In cases of transposition of the great arteries, these vessels arise from the wrong ventricle. They are "transposed" from their normal position so that the aorta arises from the right ventricle and the pulmonary artery from the left ventricle. Other heart defects may occur along with transposition of the great arteries. About 25 percent of children with transposition will also have a ventricular septal defect (VSD) . In nearly a third, the branching pattern of the coronary arteries as they leave the transposed aorta is unusual. Infants may also have narrowing below the pulmonary valve that blocks blood flow from the left ventricle to the lungs.

Sound waves enter the ear canal and make the ear drum vibrate. This action moves the tiny chain of bones (ossicles – malleus, incus, stapes) in the middle ear. The last bone in this chain 'knocks' on the membrane window of the cochlea and makes the fluid in the cochlea move.

How a woman's body changes during Pregnancy

Pregnancy is one of the beautiful phases of a woman’s life after their marriage. The feeling of the baby growing inside the womb is exceptional and very special.

Mother-to-child transmission of HIV is the spread of HIV from an HIV-infected woman to her child during pregnancy, childbirth (also called labor and delivery), or breastfeeding (through breast milk). Mother-to-child transmission of HIV is also called perinatal transmission of HIV.