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.

Knee replacement, also called arthroplasty, is a surgical procedure to resurface a knee damaged by arthritis. Metal and plastic parts are used to cap the ends of the bones that form the knee joint, along with the kneecap. This surgery may be considered for someone who has severe arthritis or a severe knee injury.

Bariatric surgical procedures cause weight loss by restricting the amount of food the stomach can hold, causing malabsorption of nutrients, or by a combination of both gastric restriction and malabsorption. Bariatric procedures also often cause hormonal changes. Most weight loss surgeries today are performed using minimally invasive techniques (laparoscopic surgery). The most common bariatric surgery procedures are gastric bypass, sleeve gastrectomy, adjustable gastric band, and biliopancreatic diversion with duodenal switch. Each surgery has its own advantages and disadvantages.

Coronary artery bypass grafting (CABG) is a type of surgery that improves blood flow to the heart. Surgeons use CABG to treat people who have severe coronary heart disease (CHD). CHD is a disease in which a waxy substance called plaque (plak) builds up inside the coronary arteries.

Here we’ll explain the symptoms of pancreatitis, how alcohol causes the condition and the other health problems it can lead to. You probably don’t pay much attention to your pancreas. But that small, tadpole-shaped organ behind your stomach and below your ribcage is pretty important. It produces two essential substances: digestive juices which your intestines use to break down food, and hormones that are involved in digestion, such as insulin, which regulates your blood sugar levels. Pancreatitis is when your pancreas becomes inflamed and its cells are damaged. Heavy drinking can cause pancreatitis. But if you drink within the government’s low risk unit guidelines, you should avoid upsetting this important organ.

Blood clotting, or coagulation, is an important process that prevents excessive bleeding when a blood vessel is injured. Platelets (a type of blood cell) and proteins in your plasma (the liquid part of blood) work together to stop the bleeding by forming a clot over the injury.

Nasal polyps are soft, painless, noncancerous growths on the lining of your nasal passages or sinuses. They hang down like teardrops or grapes. They result from chronic inflammation due to asthma, recurring infection, allergies, drug sensitivity or certain immune disorders.

Four-Step Guide to ABG Analysis Is the pH normal, acidotic or alkalotic? Are the pCO2 or HCO3 abnormal? Which one appears to influence the pH? If both the pCO2 and HCO3 are abnormal, the one which deviates most from the norm is most likely causing an abnormal pH. Check the pO2. Is the patient hypoxic?

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.

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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Pericardiocentesis is the aspiration of fluid from the pericardial space that surrounds the heart. This procedure can be life saving in patients with cardiac tamponade, even when it complicates acute type A aortic dissection and when cardiothoracic surgery is not available. [1] Cardiac tamponade is a time sensitive, life-threatening condition that requires prompt diagnosis and management. Historically, the diagnosis of cardiac tamponade has been based on clinical findings. Claude Beck, a cardiovascular surgeon, described 2 triads of clinical findings that he found associated with acute and chronic cardiac tamponade. The first of these triads consisted of hypotension, an increased venous pressure, and a quiet heart. It has come to be recognized as Beck's triad, a collection of findings most commonly produced by acute intrapericardial hemorrhage. Subsequent studies have shown that these classic findings are observed in only a minority of patients with cardiac tamponade. [2] The detection of pericardial fluid has been facilitated by the development and continued improvement of echocardiography. [3] Cardiac ultrasound is now accepted as the criterion standard imaging modality for the assessment of pericardial effusions and the dynamic findings consistent with cardiac tamponade. With echocardiography, the location of the effusion can be identified, the size can be estimated (small, medium, or large), and the hemodynamic effects can be examined by assessing for abnormal septal motion, right atrial or right ventricular inversion, and decreased respiratory variation of the diameter of the inferior vena cava.

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.

Our calculator can help you discover the most fertile days of your menstrual cycle or your “Estimated Fertility Window” based on information you provide.

CPAP is a treatment that uses mild air pressure to keep your breathing airways open. It involves using a CPAP machine that includes a mask or other device that fits over your nose or your nose and mouth, straps to position the mask, a tube that connects the mask to the machine’s motor, and a motor that blows air into the tube. CPAP is used to treat sleep-related breathing disorders including sleep apnea. It also may be used to treat preterm infants who have underdeveloped lungs.

High Resolution Upper Airway Anatomy

Gastroparesis -- literally “paralyzed stomach” -- is a serious condition manifested by delayed emptying of stomach contents into the small intestine after a meal. There is no cure for gastroparesis, but treatment can speed gastric emptying and relieve gastrointestinal symptoms such as nausea and vomiting.

The superior sagittal sinus (also known as the superior longitudinal sinus), within the human head, is an unpaired area along the attached margin of falx cerebri. It allows blood to drain from the lateral aspects of anterior cerebral hemispheres to the confluence of sinuses.

Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterised by an exaggerated response of the immune system (a hypersensitivity response) to the fungus Aspergillus (most commonly Aspergillus fumigatus). It occurs most often in patients with asthma or cystic fibrosis.