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Neurotransmitter 3D Animation
on Tuesday, December 21, 2010
Neurotransmitters are endogenous chemicals which transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to receptors in the membrane on the postsynaptic side of the synapse. Release of neurotransmitters usually follows arrival of an action potential at the synapse, but may also follow graded electrical potentials. Low level "baseline" release also occurs without electrical stimulation. Neurotransmitters are synthesized from plentiful and simple precursors, such as amino acids, which are readily available from the diet and which require only a small number of biosynthetic steps to convert. The chemical identity of neurotransmitters is often difficult to determine experimentally. For example, it is easy using an electron microscope to recognize vesicles on the presynaptic side of a synapse, but it may not be easy to determine directly what chemical is packed into them. The difficulties led to many historical controversies over whether a given chemical was or was not clearly established as a transmitter. In an effort to give some structure to the arguments, neurochemists worked out a set of experimentally tractable rules. According to the prevailing beliefs of the 1960s, a chemical can be classified as a neurotransmitter if it meets the following conditions: * There are precursors and/or synthesis enzymes located in the presynaptic side of the synapse. * The chemical is present in the presynaptic element. * It is available in sufficient quantity in the presynaptic neuron to affect the postsynaptic neuron; * There are postsynaptic receptors and the chemical is able to bind to them. * A biochemical mechanism for inactivation is present. There are many different ways to classify neurotransmitters. Dividing them into amino acids, peptides, and monoamines is sufficient for some classification purposes. Major neurotransmitters: * Amino acids: glutamate, aspartate, D-serine, γ-aminobutyric acid (GABA), glycine * Monoamines and other biogenic amines: dopamine (DA), norepinephrine (noradrenaline; NE, NA), epinephrine (adrenaline), histamine, serotonin (SE, 5-HT), melatonin * Others: acetylcholine (ACh), adenosine, anandamide, nitric oxide, etc. In addition, over 50 neuroactive peptides have been found, and new ones are discovered regularly. Many of these are "co-released" along with a small-molecule transmitter, but in some cases a peptide is the primary transmitter at a synapse. β-endorphin is a relatively well known example of a peptide neurotransmitter; it engages in highly specific interactions with opioid receptors in the central nervous system. Single ions, such as synaptically released zinc, are also considered neurotransmitters by some[by whom?], as are some gaseous molecules such as nitric oxide (NO) and carbon monoxide (CO). These are not classical neurotransmitters by the strictest definition, however, because although they have all been shown experimentally to be released by presynaptic terminals in an activity-dependent way, they are not packaged into vesicles. By far the most prevalent transmitter is glutamate, which is excitatory at well over 90% of the synapses in the human brain. The next most prevalent is GABA, which is inhibitory at more than 90% of the synapses that do not use glutamate. Even though other transmitters are used in far fewer synapses, they may be very important functionally—the great majority of psychoactive drugs exert their effects by altering the actions of some neurotransmitter systems, often acting through transmitters other than glutamate or GABA. Addictive drugs such as cocaine and amphetamine exert their effects primarily on the dop
Sexually Transmitted Diseases (STDs) affect millions of people each year. The most common STDs are gonorrhea, chlamydia and trichomoniasis. While even thinking about STDs and whether you may have one is scary, knowing the facts can make a big difference in your long-term health. Here is what you need to know:
People who are sexually active with multiple partners and are not using barrier protection are at most risk. Teenagers are a large part of this group, because they dont always practice safe sex and they are more likely to have multiple partners. It is recommended that women who are sexually active with multiple partners get screened yearly or immediately after they have engaged in unprotected sex. If you discover that you have an STD, both you and your partner would most likely be treated with antibiotics.
Gonorrhea
Approximately 350,000 cases of gonorrhea were reported to the CDC in 2006, but because not everyone is getting tested for STDs, experts believe the actual numbers are twice that.
The symptoms for gonorrhea are burning with urination, abnormal discharge or pelvic pain. Pelvic pain indicates a very severe infection. Untreated gonorrhea can lead to a serious infection as the disease may spread to a womans fallopian tubes and cause infertility.
Chlamydia
There were 1,000,000 cases of chlamydia reported to the CDC in 2006; experts think the actual rate of infection is as high as 2,000,000 cases.
Chlamydia is often called the silent disease because many people with chlamydia have no symptoms. Chlamydia can affect the urethra, the vagina, the cervix and the fallopian tubes. Symptoms include burring with urination, abnormal discharge and pelvic pain. If you are experiencing any of these systems you should see your doctor to determine if you have chlamydia. Women with chlamydia who arent treated are likely to develop pelvic inflammatory disease. Pelvic inflammatory disease occurs when the infection spreads and causes scarring to the uterus and fallopian tubes. Untreated chlamydia can result in infertility.
Trichomoniasis
Trichomoniasis is the most common STD. About 7 million women and men have trichomoniasis. Women who have trichomoniasis will often experience a frothy yellow or green discharge coming from their vagina. But some people wont have any symptoms.
Understanding STDs, what causes them, and how to treat them will help you stay in control of your health.
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are many types of anemia. Pernicious anemia is a decrease in red blood cells that occurs when the intestines cannot properly absorb vitamin B12.
A small spontaneous pneumothorax may resolve without treatment; a pneumothorax arising as a result of lung disease or injury requires immediate treatment. Treatment may include insertion of a chest tube or aspiration of the free air in the chest cavity.
Labia minoraplasty is an elective procedure that can reduce the size and reshape the inner vaginal lips. Large or asymmetrical labia minora can leave you feeling self-conscience in tight clothing or during intimacy. Long labia may result in rubbing, irritation or discomfort during intercourse and exercise. Certain skin conditions can cause increased sensitivity or tearing of the labia minora. In some cases, the labia minora may be fused with tissue in the labia majora and require medical correction.
The term "miniaturization" is widely accepted in our vernacular as a positive step in product development. Reducing components to create less space, product footprint and more affordable medical devices are ongoing objectives for manufacturers today. Jabil strives to integrate new innovative technologies into product design and manufacturing as continual miniaturization of medical devices is a focus of the healthcare thought process. Miniaturization is a constantly moving target. Once a novel, new technology sets a higher bar for miniaturization standards, the next ambitious goal is to achieve an even thinner and smaller device. Industry trends, including minimally invasive surgical devices and home health care delivery, demand more sophisticated medical portable devices and easy-to-use electronics which may not be a core competency of medical device manufacturers.
A simple continuous stitch can be a useful technique for skin closure when speed is important, e.g. closing a scalp laceration on a screaming child. The simple running, or continuous suture, is begun in the same way as a simple interrupted suture.
A gastroscopy is a procedure where a thin, flexible tube called an endoscope is used to look inside the oesophagus (gullet), stomach and first part of the small intestine (duodenum). It's also sometimes referred to as an upper gastrointestinal endoscopy. The endoscope has a light and a camera at one end.
Pancreatic Auto Islet Transplantation is a procedure used to maintain insulin production and secretion in patients with chronic pancreatitis that are undergoing a total pancreatectomy, or removal of the entire pancreas. When all other medical therapies fail to control the pain, removal of the pancreas may be an option; however it can leave a person diabetic, which means that the body can no longer control blood sugar levels, and will require intensive testing of blood sugar and injections of insulin. The pancreas is an organ, located in the upper abdominal cavity, behind the stomach, liver and colon. Within the pancreas, specialized clusters of cells known as islets produce insulin, which maintain healthy blood sugar levels. The pancreas also produces enzymes to help digest food. In order to alleviate pain and maintain insulin production, the pancreas is removed from the body, processed and the islets are harvested. Once the pancreas is removed, it is placed in a solution and put into a machine where the pancreas is digested. The islets are then infused into the patient’s liver. Within a short time, the islets are expected to start producing insulin. In 80% of patients, the pain from pancreatitis is relieved by a total pancreatectomy. Over time, some patients may be diabetic and will need to take insulin to maintain healthy blood sugar levels. All patients will take pancreatic enzymes to help digest food after surgery.
This video: Patent ductus arteriosus (PDA) is a persistent opening between two major blood vessels leading from the heart. The opening, called the ductus arteriosus, is a normal part of a baby's circulatory system before birth that usually closes shortly after birth. If it remains open, however, it's called a patent ductus arteriosus. A small patent ductus arteriosus often doesn't cause problems and might never need treatment. However, a large patent ductus arteriosus left untreated can allow poorly oxygenated blood to flow in the wrong direction, weakening the heart muscle and causing heart failure and other complications. Treatment options for a patent ductus arteriosus include monitoring, medications and closure by cardiac catheterization or surgery.
our uterus (or womb) is normally held in place inside your pelvis with various muscles, tissue, and ligaments. Because of pregnancy, childbirth or difficult labor and delivery, in some women these muscles weaken. Also, as a woman ages and with a natural loss of the hormone estrogen, her uterus can drop into the vaginal canal, causing the condition known as a prolapsed uterus.
Adult stem cells are cells from your own body that can renew themselves and turn into other cells (differentiate). They live inside all of us in various tissues, poised to leap into action to repair damage as it occurs. As we age or have big injuries, we may not be able to recruit enough of these cells to the site to fully repair the area. Regenexx Stem Cell Procedures help overcome this problem by extracting stem cells from an area of high volume, then concentrating the cells and reinjecting them into the damaged area to help the body heal naturally.
Hypertrophic cardiomyopathy (HCM) is very common and can affect people of any age. It affects men and women equally. It is a common cause of sudden cardiac arrest in young people, including young athletes. Hypertrophic cardiomyopathy occurs if heart muscle cells enlarge and cause the walls of the ventricles (usually the left ventricle) to thicken. The ventricle size often remains normal, but the thickening may block blood flow out of the ventricle. If this happens, the condition is called obstructive hypertrophic cardiomyopathy. Sometimes the septum, the wall that divides the left and right sides of the heart, thickens and bulges into the left ventricle. This can block blood flow out of the left ventricle. Then the ventricle must work hard to pump blood. Symptoms can include chest pain, dizziness, shortness of breath, or fainting. Hypertrophic cardiomyopathy also can affect the heart's mitral valve, causing blood to leak backward through the valve. Sometimes, the thickened heart muscle doesn't block blood flow out of the left ventricle. This is referred to as non-obstructive hypertrophic cardiomyopathy. The entire ventricle may thicken, or the thickening may happen only at the bottom of the heart. The right ventricle also may be affected. In both obstructive and non-obstructive HCM, the thickened muscle makes the inside of the left ventricle smaller, so it holds less blood. The walls of the ventricle may stiffen, and as a result, the ventricle is less able to relax and fill with blood.
Electrical cardioversion is a procedure in which an electric current is used to reset the heart's rhythm back to its regular pattern (normal sinus rhythm). The low-voltage electric current enters the body through metal paddles or patches applied to the chest wall.