There's only one group of people who really know what happens when you die: the dead. And since the dead won't be revealing their secrets anytime soon, it's up to scientists to explain what happens when a person dies. Death, just like life, is a process, scientists say. The first stage of this process is known as clinical death. It lasts from four to six minutes, beginning when a person stops breathing and the heart stops pumping blood. During this time, there may be enough oxygen in the brain that no permanent brain damage occurs. Other organs, such as the kidneys and eyes, also remain alive throughout clinical death.

The essential components of the human cardiovascular system are the heart, blood and blood vessels. It includes the pulmonary circulation, a "loop" through the lungs where blood is oxygenated; and the systemic circulation, a "loop" through the rest of the body to provide oxygenated blood.

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A bowel obstruction happens when either your small or large intestine is partly or completely blocked. The blockage prevents food, fluids, and gas from moving through the intestines in the normal way. The blockage may cause severe pain that comes and goes. This topic covers a blockage caused by tumors, scar tissue, or twisting or narrowing of the intestines. It does not cover ileus, which most commonly happens after surgery on the belly (abdominal surgery). What causes a bowel obstruction? Tumors, scar tissue (adhesions), or twisting or narrowing of the intestines can cause a bowel obstruction. These are called mechanical obstructions . In the small intestine, scar tissue is most often the cause. Other causes include hernias and Crohn's disease, which can twist or narrow the intestine, and tumors, which can block the intestine. A blockage also can happen if one part of the intestine folds like a telescope into another part, which is called intussusception.

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The arm and leg muscles are affected later. Myasthenia gravis (MG) is an autoimmune disease — a disease that occurs when the immune system attacks the body's own tissues. In MG, that attack interrupts the connection between nerve and muscle — the neuromuscular junction.

There are a number of different causes of vertigo. Vertigo can be defined based upon whether the cause is peripheral or central. Central causes of vertigo arise in the brain or spinal cord while peripheral vertigo is due to a problem within the inner ear. The inner ear can become inflamed because of illness, or small crystals or stones found normally within the inner ear can become displaced and cause irritation to the small hair cells within the semicircular canals, leading to vertigo. This is known as benign paroxysmal positional vertigo (BPPV).

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Papillary fibroelastoma is the third most common primary tumor of the heart and is most likely to involve the cardiac valves. Like myxomas, they arise from the endocardium in most patients and since these tumors are often incidental findings at echocardiography or autopsy, the true incidence is difficult to estimate. Most patients are older than 60 years, which also contrasts with myxomas. Papillary fibroelastomas can embolize, leading to severe neurological complications and therefore, surgical removal is advised, although there is controversy regarding small incidental lesions and the need for surgery.

An ectopic pregnancy results when a fertilized egg implants outside the uterus. Unfortunately, there's no way to transplant an ectopic pregnancy into your uterus, so ending the pregnancy is the only option. About 2 percent of pregnancies are ectopic. Because ectopic pregnancy is potentially dangerous for you, it's important to recognize the early signs and get treatment as soon as possible.

Paracentesis is a procedure to take out fluid that has collected in the belly (peritoneal fluid). This fluid buildup is called ascites camera.gif. Ascites may be caused by infection, inflammation, an injury, or other conditions, such as cirrhosis or cancer. The fluid is taken out using a long, thin needle put through the belly. The fluid is sent to a lab and studied to find the cause of the fluid buildup. Paracentesis also may be done to take the fluid out to relieve belly pressure or pain in people with cancer or cirrhosis.

Frostbite is an injury caused by freezing of the skin and underlying tissues. First your skin becomes very cold and red, then numb, hard and pale. Frostbite is most common on the fingers, toes, nose, ears, cheeks and chin. Exposed skin in cold, windy weather is most vulnerable to frostbite. But frostbite can occur on skin covered by gloves or other clothing. Frostnip, the first stage of frostbite, doesn't cause permanent skin damage. You can treat very mild frostbite with first-aid measures, including rewarming your skin. All other frostbite requires medical attention because it can damage skin, tissues, muscle and bones. Possible complications of severe frostbite include infection and nerve damage.

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irregular, curved toenails. footwear that places a lot of pressure on the big toes, such as socks and stockings that are too tight or shoes that are too tight, narrow, or flat for your feet. toenail injury, including stubbing your toe, dropping something heavy on your foot, or kicking a ball repeatedly. poor posture. How can ingrowing toenails be prevented? Cut your nails straight across; do not cut them too short or too low at the sides. ... Keep your feet clean and dry. ... Avoid tight shoes and use cotton socks rather than synthetic. If you have diabetes, you should take extra care when cutting your nails:

Genital warts are growths on the skin of the genital area and around the anus. They are caused by certain types of the human papilloma virus (HPV). There are more than 100 types of HPV. Some types of HPV produce warts on different parts of the body, like plantar warts on the feet and common hand warts. There is no specific treatment for HPV, but there are treatments for health problems caused by HPV. Genital warts can be treated by your healthcare provider, or with prescription medication. HPV-related cancers are more treatable when diagnosed and treated promptly. For more information, visit www.cancer.org.

Yannas had been studying collagen, a protein found in human skin. Teaming up during the 1970s, the two made a polymer (a chemical compound made of multiple repeating units). Using collagen fibers and a long sugar molecule, they formed a porous (full of small holes) material resembling skin.

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.

Chronic myeloid leukaemia is a common malignancy worldwide. We have come a long way from the limited treatment options and survival in this condition. Today, CML is a treatable malignancy with more than 80% patients surviving beyond 10 years after diagnosis, in absence of complications. This presentation deals with the definition, diagnostic criteria of chronic phase, accelerated and blastic phase (MD Anderson cancer centre, International bone marrow transplant registry and the WHO for the latter two) and management (first and second generation tyrosine kinase inhibitors) of this condition. Finally, a stepwise approach to chronic myeloid leukaemia is also presented including the definitive modality of treatment, allogeneic stem cell transplantation.

Methotrexate works by reducing the function of the cells that are causing inflammation in the joint tissues. "Its use can reduce inflammation and therefore should help relieve pain and protect from joint damage," notes Sean A. Whelton, MD, a rheumatologist and associate professor of medicine at MedStar Georgetown University Hospital in Washington, D.C. Less inflammation in the joints should mean less joint pain and less joint swelling. You should also feel less fatigue and less morning stiffness.