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A hormone is a chemical messenger that enables communication between cells. Hormones are secreted by the glands of the endocrine system and they serve to maintain homeostasis and to regulate numerous other systems and processes, including reproduction and development.
The ureter can become obstructed due to conditions such as kidney stones, tumors, infection, or blood clots. When this happens, physicians can use image guidance to place stents or tubes in the ureter to restore the flow of urine to the bladder. A ureteral stent is a thin, flexible tube threaded into the ureter.
This animation demonstrates how a unilateral complete cleft lip repair is performed. This video is meant for educational purposes for patients and families. There are many ways to fix a complete cleft lip, but the technique shown here is the most common known as the Millard Rotation Advancement Repair.
Human immunodeficiency virus infection / acquired immunodeficiency syndrome (HIV/AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV).[1] During the initial infection a person may experience a brief period of influenza-like illness. This is typically followed by a prolonged period without symptoms. As the illness progresses it interferes more and more with the immune system, making people much more likely to get infections, including opportunistic infections, and tumors that do not usually affect people with working immune systems.
HIV is transmitted primarily via unprotected sexual intercourse (including anal and even oral sex), contaminated blood transfusions and hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding.[2] Some bodily fluids, such as saliva and tears, do not transmit HIV.[3] Prevention of HIV infection, primarily through safe sex and needle-exchange programs, is a key strategy to control the spread of the disease. There is no cure or vaccine; however, antiretroviral treatment can slow the course of the disease and may lead to a near-normal life expectancy. While antiretroviral treatment reduces the risk of death and complications from the disease, these medications are expensive and may be associated with side effects.
Genetic research indicates that HIV originated in West-central Africa during the early twentieth century.[4] AIDS was first recognized by the Centers for Disease Control and Prevention (CDC) in 1981 and its cause—HIV infection—was identified in the early part of the decade.[5] Since its discovery, AIDS has caused nearly 30 million deaths (as of 2009).[6] As of 2010, approximately 34 million people have contracted HIV globally.[7] AIDS is considered a pandemic—a disease outbreak which is present over a large area and is actively spreading.[8]
HIV/AIDS has had a great impact on society, both as an illness and as a source of discrimination. The disease also has significant economic impacts. There are many misconceptions about HIV/AIDS such as the belief that it can be transmitted by casual non-sexual contact. The disease has also become subject to many controversies involving religion.
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.