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Adrenal medulla
Adrenal medulla "The inner portion of adrenal gland. (The outer portion is the adrenal cortex). The adrenal medulla makes epinephrine (adrenaline) and norepinephrine (noradrenaline). Epinephrine is secreted in response to low blood levels of glucose as well as exercise and stress; it causes the breakdown of the storage product glycogen to the sugar glucose in the liver, facilitates the release of fatty acids from adipose (fat) tissue, causes dilation (widening) of the small arteries within muscle and increases the output of the heart. Norepinephrine secreted by the adrenal gland acts to narrow blood vessels and raise blood pressure. Underfunction of the adrenal medulla is virtually unknown. However, a tumor called a pheochromocytoma produces norepinephrine and epinephrine and is equivalent to overfunction of the adrenal medulla. Pheochromocytomas arise within the adrenal medulla or elsewhere in the sympathetic nervous system. They typically cause hypertension (high blood pressure) that may be paroxysmal (sharply episodic) with attacks of headaches, feelings of apprehension, sweating, flushing of the face, nausea and vomiting, palpitations and tingling of the extremities (the arms and legs)."
RELATED TERMS--------------------------------------
Gland
An organ that releases a chemical. Endocrine glands are ductless and secrete hormones directly into the bloodstream. Exocrine glands secrete externally, either through a tube or duct.
Medulla
The inner part of an organ. The adrenal medulla is the center of the adrenal gland where epinephrine (adrenaline) is produced.
Epinephrine
One of two chemicals (the other is norepinephrine) released by the adrenal gland that increases the speed and force of heart beats. It dilates the airways to improve breathing and narrows blood vessels in the skin and intestine so that an increased flow of blood reaches the muscles and allows them to cope with the demands of exercise.
Norepinephrine
A hormone produced by the adrenal glands that also acts as a neurotransmitter for nerve cells. Part of the fight-or-flight response.
Blood
The life-maintaining fluid which is made up of plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets; blood circulates through the body's heart, arteries, veins, and capillaries; it carries away waste matter and carbon dioxide, and brings nourishment, electrolytes, hormones, vitamins, antibodies, heat, and oxygen to the tissues.
Glucose
The only simple carbohydrate that circulates in the bloodstream. Glucose is the primary fuel used by the brain. It can also be stored in the liver and muscles in a polymer form known as glycogen.
Stress
Mental or physical tension that results from physical, emotional, or chemical causes.
Glycogen
The storage form of glucose. Only glycogen from the liver can be used to restore blood glucose levels.
Sugar
A class of carbohydrates that taste sweet. Sugar is a quick and easy fuel for the body to use. Types of sugar are lactose, glucose, fructose, and sucrose.
Liver
The largest organ in the body. The liver carries out many important functions, such as making bile, changing food into energy, and cleaning alcohol and poisons from the blood.
Adipose
"""Adipose"" means ""fat"" but is usually used to refer specifically to tissue made up of mainly fat cells such as the yellow layer of fat beneath the skin. The word ""adipose"" comes from the Latin ""adeps"" meaning ""fat, particularly lard."""
Tissue
Biological tissue is a group of cells that perform a similar function.The study of tissues is known as histology, or, in connection with disease, histopathology.The classical tools for studying the tissues are the wax block, the tissue stain, and the optical microscope, though developments in electron microscopy, immunofluorescence, and frozen sections have all added to the sum of knowledge in the last couple of decades.
Dilation
The opening of the cervix during labor.
Arteries
Blood vessels that carry blood away from the heart to the arms, legs, head, body and organs.
Muscle
Tissue made up of bundles of long, slender cells that contract when stimulated.
Heart
The hollow, muscular organ responsible for pumping blood through the circulatory system.
Tumor
Overgrowth of tissue.
Pheochromocytoma
A small tumor of chromaffin cells, usually of the adrenal medulla, but occasionally of the chromaffin tissue of sympathetic paraganglia. Functional tumors secrete catecholamines.
Hypertension
Higher blood pressure than normal. Diastolic blood pressure from 90 to 99 mm HG is considered mild hypertension; 100–109, moderate hypertension; and 110 or greater, severe hypertension. Systolic blood pressure from 140 to 159 mm HG is considered mild hypertension; 160–179, moderate hypertension; and 180 or greater, severe hypertension.
Nausea
The feeling of wanting to throw up (vomit).
Vomiting
The release of stomach contents through the mouth.
Arms
An appendage in anatomy and in clinical trials. See: Arm.
SIMILAR TERMS--------------------------------------
Adrenal cortex
The outer portion of the adrenal gland that secretes hormones that are vital to the body.
Adrenal failure
A condition in which the adrenal glands do not produce enough of the adrenal hormones that control important functions such as blood pressure. The adrenal glands sit on top of the kidneys. The adrenal is made up of an outer layer (the cortex) and an inner portion (the medulla). The adrenal glands produce hormones that help control the heart rate, blood pressure, the way the body uses food, and other vital functions. The adrenal cortex secretes steroid (cortisone-related) hormones and mineralocortoids that regulate the levels of minerals such as sodium and potassium in the blood.
Adrenal gland
The pair of adrenal glands are located on top of both kidneys. Adrenal glands work hand-in-hand with the hypothalamus and pituitary gland.
Adrenal glands
Two glands, one on top of each kidney, which produce a variety of hormones that affect nearly every body system.
Adrenaline
Or epinephrine. One of two chemicals (the other is norepinephrine) released by the adrenal gland that increases the speed and force of heartbeats. It dilates the airways to improve breathing and narrows blood vessels in the skin and intestine so that an increased flow of blood reaches the muscles and allows them to cope with the demands of exercise.
Adrenals
Located on the top of the kidneys, these glands that are responsible for the production of stress-related hormones such as cortisol, DHEA, and adrenaline.
Adrenergic
This refers to neuronal or neurologic activity caused by neurotransmitters such as epinephrine, norepinephrine, and dopamine.
Adrenocortical carcinoma
Adrenocortical carcinoma is a carcinoma of the cortex (outer layer) of the adrenal gland. While most tumors of the adrenal cortex are benign (adenomas) and only occasionally cause Cushing's syndrome, the malignant form makes up about 3% of all cortical tumors and requires surgery and sometimes chemotherapy. Excess cortisol production may require suppression with ketoconazole or metyrapone. Production of aldosterone or androgens by carcinomas is extremely rare.
Adrenocortical hormone
One of the hormones, for example cortisol, secreted not from the internal medulla but from the external cortex of the bilateral adrenocortical glands.
Adrenocortiotrophic hormone
The hormone released from the pituitary gland. It interacts with receptors on the adrenal gland to begin the process of cortisol and DHEA production. ACTH uses the second messenger cyclic AMP to signal target cells in the adrenal gland.
Adrenoleukodystrophy
A rare genetic (inherited) disorder characterized by the breakdown or loss of the myelin sheath surrounding nerve cells in the brain and progressive dysfunction of the adrenal gland. Adrenoleukodystrophy (ALD) is one of a group of genetic disorders called the leukodystrophies that cause damage to the myelin sheath of the nerve fibers in the brain. The myelin sheath is a fatty covering which acts as an electrical insulator.
PREVIOUS AND NEXT TERMS--------------------------------------
Admission
Entry. As a patient admission (into a hospital). The opposite of admission in this context is discharge.
Admitting physician
The doctor responsible for admitting a patient to a hospital or other inpatient health facility.
Adnexa
"This Latin word (in the plural) is used in medicine in reference to appendages. For example, in gynecology the adnexa are the ""appendages"" of the uterus, namely the ovaries, Fallopian tubes and ligaments that hold the uterus in place."
ADR
Adverse drug reaction. See: Adverse reaction.
Adrenal failure
A condition in which the adrenal glands do not produce enough of the adrenal hormones that control important functions such as blood pressure. The adrenal glands sit on top of the kidneys. The adrenal is made up of an outer layer (the cortex) and an inner portion (the medulla). The adrenal glands produce hormones that help control the heart rate, blood pressure, the way the body uses food, and other vital functions. The adrenal cortex secretes steroid (cortisone-related) hormones and mineralocortoids that regulate the levels of minerals such as sodium and potassium in the blood.
Adrenal medulla
Adrenoleukodystrophy
A rare genetic (inherited) disorder characterized by the breakdown or loss of the myelin sheath surrounding nerve cells in the brain and progressive dysfunction of the adrenal gland. Adrenoleukodystrophy (ALD) is one of a group of genetic disorders called the leukodystrophies that cause damage to the myelin sheath of the nerve fibers in the brain. The myelin sheath is a fatty covering which acts as an electrical insulator.
ADU
Accessory dwelling unit.
Adult acne
Popular name for rosacea. For more information, see: Rosacea.
Adult primary liver cancer
A tumor in which the cancer starts during adulthood in cells in the liver. Also called hepatocellular carcinoma. Primary liver cancer is different from cancer that has metastasized (spread) from another place in the body to the liver.
Adult respiratory distress syndrome
Better known as ARDS. See: ARDS.
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