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.

Asthma is a condition in which your airways narrow and swell and produce extra mucus. This can make breathing difficult and trigger coughing, wheezing and shortness of breath.

Cells may have slender extensions of the cell membrane to form cilia or the smaller extensions called microvilli. The microscopic microvilli effectively increase the surface area of the cell and are useful for absorption and secretion functions. A dramatic example is the human small intestine. The tissue has small fingerlike extensions called villi which are collections of cells, and those cells have many microvilli to even further increase the available surface area for the digestion process. According to Audesirk & Audesirk, this can give an effective surface area of about 250 square meters for absorption.

Ebola virus disease (EVD; also Ebola hemorrhagic fever, or EHF), or simply Ebola, is a viral hemorrhagic fever of humans and other primates caused by ebolaviruses. Signs and symptoms typically start between two days and three weeks after contracting the virus with a fever, sore throat, muscular pain, and headaches.

Recovery can take 4 to 6 months, depending on the size of the tear and other factors. You may have to wear a sling for 4 to 6 weeks after surgery. Pain is usually managed with medicines. Physical therapy can help you regain the motion and strength of your shoulder.

Elbow. In primates, including humans, the elbow joint is the synovial hinge joint between the humerus in the upper arm and the radius and ulna in the forearm which allows the hand to be moved towards and away from the body.

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A facet joint injection is a relatively simple, straightforward procedure, and is usually performed in an office based procedure suite or in an ambulatory surgical center. As with many spinal injections, facet joint injections are best performed using fluoroscopy (live X-ray) for guidance to properly target and place the needle (and to help avoid nerve injury or other injury).

Rheumatic heart disease (RHD) is the most common acquired heart disease in children in many countries of the world, especially in developing countries. The global burden of disease caused by rheumatic fever currently falls disproportionately on children living in the developing world, especially where poverty is widespread. RHD is a chronic heart condition caused by rheumatic fever that can be prevented and controlled. Rheumatic fever is caused by a preceding group A streptococcal (strep) infection. Treating strep throat with antibiotics can prevent rheumatic fever. Moreover, regular antibiotics (usually monthly injections) can prevent patients with rheumatic fever from contracting further strep infections and causing progression of valve damage. Consequences of rheumatic heart disease Acute rheumatic fever primarily affects the heart, joints and central nervous system. The major importance of acute rheumatic fever is its ability to cause fibrosis of heart valves, leading to crippling valvular heart disease, heart failure and death. The decline of rheumatic fever in developed countries is believed to be the result of improved living conditions and availability of antibiotics for treatment of group A streptococcal infection. Overcrowding, poor housing conditions, undernutrition and lack of access to healthcare play a role in the persistence of this disease in developing countries.

Rheumatic fever is an inflammatory disease that can develop as a complication of inadequately treated strep throat or scarlet fever. Strep throat and scarlet fever are caused by an infection with streptococcus bacteria. Rheumatic fever is most common in 5- to 15-year-old children, though it can develop in younger children and adults. Although strep throat is common, rheumatic fever is rare in the United States and other developed countries. However, rheumatic fever remains common in many developing nations. Rheumatic fever can cause permanent damage to the heart, including damaged heart valves and heart failure. Treatments can reduce damage from inflammation, lessen pain and other symptoms, and prevent the recurrence of rheumatic fever.

Surfactant. Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants.

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The DASH diet is a lifelong approach to healthy eating that's designed to help treat or prevent high blood pressure (hypertension). The DASH diet encourages you to reduce the sodium in your diet and eat a variety of foods rich in nutrients that help lower blood pressure, such as potassium, calcium and magnesium.

Nelson syndrome refers to a spectrum of symptoms and signs arising from an adrenocorticotropin (ACTH)–secreting pituitary macroadenoma after a therapeutic bilateral adrenalectomy. The spectrum of clinical features observed relates to the local effects of the tumor on surrounding structures, the secondary loss of other pituitary hormones, and the effects of the high serum concentrations of ACTH on the skin. [1] The first case was reported by Nelson et al in 1958. [2]

Kyphosis, also known as a round back or hunchback, is a condition in which the spine in the upper back has an excessive curvature. The upper back, or thoracic region of the spine, is supposed to have a slight natural curve.

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Herpes simplex encephalitis is characterized by acute-onset (<1 week) fever, headaches, seizures, altered mental status, and focal neurologic findings such as hemiparesis or cranial nerve deficits. This patient's weakness/fatigue for >1 week, heart murmur, history of drug abuse, and absence of focal neurologic deficits make endocarditis with mycotic aneurysm more likely than herpes encephalitis

Acute intermittent porphyria (AIP) is a rare autosomal dominant metabolic disorder affecting the production of heme, the oxygen-binding prosthetic group of hemoglobin. It is characterized by a deficiency of the enzyme porphobilinogen deaminase.

Uncomplicated acute otitis media (AOM) should be treated empirically with amoxicillin. Recurrent AOM should raise concern for beta-lactamase resistance and warrants treatment with amoxicillin-clavulanic acid. Ototopical medications are unnecessary, even if there is tympanic membrane perforation.