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| Organic compound containing carbon, hydrogen, oxygen, and nitrogen, essential for the conduction of nerve impulses in animals. It is found in highest concentrations on neuron surfaces and is liberated at nerve cell endings. There is strong evidence that acetylcholine is the transmitter substance that conducts impulses from one cell to another in the parasympathetic nervous system, and from nerve cells to smooth muscle, skeletal muscle, and exocrine glands. |
| Pair of small endocrine glands situated atop the kidneys. The outer yellowish layer (cortex) secretes about 30 steroid hormones, most importantly aldosterone, which regulates water and salt balance in the body, and cortisol, which controls carbohydrate, fat, and protein metabolism. The inner reddish portion (medulla) of the adrenals secretes the emergency-response hormones EPINEPHRINE (adrenaline) and norepinephrine. |
| Chronic respiratory disorder characterized by labored breathing and wheezing resulting from obstructed and constricted air passages. Although asthma usually results from an allergic reaction (see ALLERGY), specific allergens are not always identifiable. Illness and stress may precipitate an attack. Long-term control includes inhaled or oral bronchodilators (albuterol, theophylline), breathing exercises, and, if possible, the identification and avoidance of allergens. Short-term cortisone and prednisone can bring immediate relief in acute attacks. |
| Supervisory center of the NERVOUS SYSTEM in all vertebrates. The brain controls both conscious behavior (e.g., walking and thinking) and most involuntary behavior (e.g., heartbeat and breathing). In higher animals, it is also the site of emotions, memory, self-awareness, and thought. It functions by receiving information via nerve cells (neurons) from every part of the body, evaluating the data, and then sending directives to muscles and glands or simply storing the information. Information, in the form of electrochemical signals, moves through complex brain circuits, which are networks of the billions of nerve cells in the nervous system. A single neuron may receive information from as many as 1,000 other neurons. Anatomically, the brain occupies the skull cavity (cranium) and is enveloped by three protective membranes (meninges). The adult brain weighs 2 1/4 to 3 1/4 lb (1-1.5 kg). It has several parts, each with a loosely associated function. The brainstem (hindbrain), monitoring involuntary activity (e.g., breathing), and the cerebellum, coordinating muscular movements and posture, are together the basic machinery for survival and reproduction. The forebrain, composed of the limbic system and cerebral cortex, regulates higher functions. The limbic system (including the thalamus, hypothalamus, pituitary, amygdala and hippocampus, and olfactory cortex) is associated with vivid emotions, memory, sexuality, and smell. The forebrain's cerebral cortex, in the uppermost portion of the skull, has some areas concerned with muscle control and the senses and others concerned with language and anticipation of action. The cerebral cortex is split into two hemispheres, each controlling the side of the body opposite to it. In addition, the right hemisphere is associated with perception of melody, nonverbal visual patterns, and emotion, while the left hemisphere is associated with verbal skills. Brain function is monitored by ELECTROENCEPHALOGRAPHY. |
| Inflammation of the bronchial tubes caused by viral or bacterial infection or by the inhalation of irritating fumes (e.g., tobacco smoke, air pollutants). Symptoms include cough, fever, and chest pains. Acute bronchitis may subside, or, particularly with continued exposure to irritants, may persist and progress to chronic bronchitis or PNEUMONIA. Bronchitis can be treated with antihistamines, cough suppressants, bronchodilators, or ANTIBIOTICS. |
| Any of several structurally related compounds found in the body that help regulate the sympathetic NERVOUS SYSTEM. They include EPINEPHRINE (or adrenaline), NOREPINEPHRINE, and dopamine-substances that prepare the body to meet emergencies such as cold, fatigue, and shock. Epinephrine and isoproterenol, a synthetic catecholamine, are used as drugs to treat diseases such as EMPHYSEMA, BRONCHITIS, and ASTHMA. |
| Any of a group of NEUROTRANSMITTERS, affecting mood, perception of pain, memory retention, and learning. Chemically similar to opium-derived NARCOTICS, endorphins were searched for and found in the 1970s after the discovery that MORPHINE works by attaching itself to specific receptor sites in the brain. Endorphins also attach to these receptors and appear to be the brain's own natural painkillers. Besides behaving as pain regulators, endorphins are believed to contribute to euphoric feelings such as the runner's high experienced after prolonged exercise. |
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Hormone secreted by the medulla of the ADRENAL GLANDS. Strong emotions, such as fear and anger, cause epinephrine to be released into the bloodstream, producing an increase in heart rate, muscle strength, blood pressure, and sugar metabolism. This reaction, often called the fight or flight response, prepares the body for strenuous activity. In medicine, epinephrine is used chiefly as a stimulant in cardiac arrest, as a vasoconstrictor in shock, and as a bronchodilator and antispasmodic in bronchial asthma. See also CATECHOLAMINE. |
| Histamine is another powerful 'substance' your body produces naturally. It can be found in many parts of the body. Its main role is to produce gastric juice for the digestion of your food. The presence of too much histamine in your body may also cause many adverse reactions. The most common are similar to those associated with excess Serotonin, including allergies and hay fever. Treatment with drugs known to influence these hormones, or exposure to small negative ions of oxygen, can bring the body back into balance, relieving symptoms. |
| Group of drugs with potent analgesic effects, associated with alteration of mood and behavior. The chief narcotic drugs are OPIUM, CODEINE, MORPHINE, and the morphine derivative HEROIN. Narcotics are thought to act by mimicking and/or enhancing the activity of ENDORPHINS, proteins produced by the brain and believed to modulate pain and other nervous system functions. Narcotics are valuable in numbing the senses, alleviating pain, inducing sleep, and relieving diarrhea. Common side effects include nausea, vomiting, and allergic reactions. In large doses, narcotics can cause respiratory depression, COMA, and death. All narcotics are addictive; synthetic narcotics such as meperidine and METHADONE tend to be less addicting and possess fewer side effects, but they are also less potent. |
| Chemical that transmits information across the junction (synapse) that separates one nerve cell (neuron) from another nerve cell or a muscle. Neurotransmitters are stored in the nerve cell's bulbous end (axon). When an electrical impulse traveling along the nerve reaches the axon, the neurotransmitter is released and travels across the synapse, either prompting or inhibiting continued impulses. There are more than 300 known neurotransmitters, including the ENDORPHINS and ACETYLCHOLINE. |
| The NEUROTRANSMITTER that mediates chemical communication in the sympathetic NERVOUS SYSTEM. Like other neurotransmitters, it is released at synaptic nerve endings to transmit the signal from a nerve cell to other cells. It is almost identical in structure to EPINEPHRINE. The sympathetic nervous system functions in response to short-term stress (the fight or flight response); hence norepinephrine and epinephrine increase the heart rate as well as blood pressure, increase the rate of glycogen conversion for energy, and relax bronchial smooth muscle to assist breathing. |
| Chemical that transmits information across the junction (synapse) that separates one nerve cell (neuron) from another nerve cell or a muscle. Neurotransmitters are stored in the nerve cell's bulbous end (axon). When an electrical impulse traveling along the nerve reaches the axon, the neurotransmitter is released and travels across the synapse, either prompting or inhibiting continued impulses. There are more than 300 known neurotransmitters, including the ENDORPHINS and ACETYLCHOLINE. |
| Network of specialized tissue that controls actions and reactions of the body, enabling it to adjust to its environment. The system functions by receiving signals from all parts of the body, relaying them to the BRAIN and SPINAL CORD, and then sending appropriate return signals to muscles and body organs. Virtually all multicellular animals have at least a rudimentary nervous system; in vertebrates the system is most complex. The basic unit of the nervous system is the nerve cell (neuron). Of the billions of neurons in humans, half are in the brain. The neuron consists of a cell body, containing the cell nucleus; dendrites, branchlike extensions that receive incoming signals; and the axon, the long cell extension that carries signals long distances. A neuron works by receiving chemical signals-some excitatory, some inhibitory-through its dendrites and sending electrical impulses along its axon. Chemicals (NEUROTRANSMITTERS) released at the terminal fibers of the axon diffuse across a junction called the synapse and bind to dendrites of recipient neurons. Dendrites and axons are called nerve fibers; a nerve is a bundle of nerve fibers. The nervous system has two divisions: the central nervous system and peripheral nervous system. The central nervous system, consisting of the brain and spinal cord, receives impulses from receptors in the skin and organs via sensory (afferent) nerve fibers; it returns impulses via motor (efferent) fibers to terminals in muscles and glands. Peripheral nerves mediate these pathways. The peripheral nervous system comprises cranial nerves, controlling face and neck; spinal nerves, radiating to other parts of the body; and autonomic nerves, which form a subsidiary system regulating the iris of the eye and muscles of heart, glands, lungs, stomach, and other visceral organs. The autonomic nervous system, in turn, comprises the sympathetic nervous system, which functions in response to short-term stress (e.g., increasing heart rate), and the parasympathetic nervous system, which acts in opposition to the sympathetic (e.g., lowering heart rate). |
| Highly addictive NARCOTIC derivative of OPIUM used for the relief of pain. Morphine suppresses anxiety and alters the perception of pain, thereby producing euphoria. It also impairs mental and physical performance, reduces sex and hunger drives, and induces apathy. Its use is strictly regulated |
| First recognized as a powerful vasoconstrictor occurring in blood serum
and other tissues, and subsequently found in wasp and scorpion venom and
in various fruits and nuts. One role of the compound is as a NEUROTRANSMITTER
that may participate in such diverse functions as learning, sleep, and
control of mood. Its structural similarity to certain mind-altering drugs,
such as LSD, has prompted speculation that serotonin may have a role in
mental disorders, such as schizophrenia.
The Role of Serotonin is known to play a part in almost every function of the central nervous system. When the brain under or over-produces serontonin the imbalance can be reflected in distressing symptoms. Abnormally high or low serotonin levels correlate with a range of conditions including depression, psychosis, sexual dysfunction, lethargy, migraine, low pain thresholds, learning disabilities, poor sleep patterns, asthma, aggression and even suicide. Abnormal blood levels of serotonin have been shown to be present in many types of psychiatric disorders and in mental retardation. In general, high levels lead to hyperactivity, insomnia and anxiety, while low levels result in depression In 1988 the British Journal of Psychiatry published a report on 'serotonin irritation syndrome' characterised by anxiety, headaches, palpitations and insomnia. The same report listed a total of 15 conditions, ranging from alcoholism and panic disorder to ADD and Alzheimer's disease in which abnormal serotonin levels are involved. Again, exposure to negative ions was recommended as one form of treatment. |
| Length of nerve-fiber bundles carrying information (electrical and
chemical signals) through the NERVOUS SYSTEM. The
spinal cord carries sensory impulses from the trunk and limbs to the brain;
it returns commands from the brain to the muscles and glands. Anatomically,
the spinal cord runs nearly the length of the trunk and merges with the
brainstem. The spinal cord is housed within the spinal column, a bony column
that also forms the main structural support of the SKELETON. The spinal
column consists of segments (vertebrae) linked by flexible joints and held
together by gelatinous disks of cartilage and by ligaments. Each vertebra
has a roughly cylindrical body, winglike projections, and a bony arch.
The arches, positioned next to one another, create the tunnellike space
that houses the spinal cord.
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