Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «B»:
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Berzelius: See: Berzelius, Jons Jacob....
Berzelius, Jons Jacob
Berzelius, Jöns Jacob: Celebrated Swedish chemist (1779-1848).
Berzelius's early life was marked by a struggle to obtain a satisfactory education. In 1796 he entered the University of Uppsala but his studies were interrupted because of lack of funds. He began his chemical experiments without a...
Beta adrenergic blocking agents
Beta adrenergic blocking drugs: A class of drugs,
also called beta blockers, that block
beta-adrenergic substances such as adrenaline (epinephrine), a key
agent in the "sympathetic" portion of the autonomic (involuntary)
By blocking the action of the sympathetic nervous system ...
Beta agonist: See: Beta-agonist....
Beta blocker: A class of drugs that block beta-adrenergic substances such as adrenaline (epinephrine) in the "sympathetic" portion of the autonomic (involuntary) nervous system. By blocking the action of the sympathetic nervous system on the heart, beta blockers relieve stress on the heart; they slo...
Beta carotene: A vitamin that acts as an antioxidant, protecting cells against oxidation damage. Beta carotene is converted by the body to vitamin A. Food sources of beta carotene include vegetables such as carrots, sweet potatoes, spinach and other leafy green vegetables; and fruit such as cantalou...
Beta cell: A type of cell in the pancreas. Within the pancreas, the beta cells are located in areas called the islets of Langerhans where they constitute the predominant type of cell.
The beta cells make and release insulin, a hormone that controls the level of glucose (sugar) in the blood. Degener...
Beta cell, pancreatic
Beta cell, pancreatic: A type of
cell in the pancreas (the organ of the digestive system
located behind the stomach). Within the pancreas, the beta
cells are located in areas called the islets of Langerhans.
They constitute the predominant type of cell in the islets.
The beta cells are importan...
Beta error: The statistical error (said to be "of the second
kind" or type II) made in testing when it is concluded that something is negative
when it really is positive. Beta error is often referred to as a false negative....
Beta particle: An electron ejected from the nucleus of a decaying atom. Although beta particles can be stopped by a thin sheet of aluminum, they can penetrate the dead skin layer, potentially causing burns. They can pose a serious direct or external radiation threat and can be lethal depending on th...
Beta protein 1
Beta protein 1: Abbreviated and better known as BP1. See: BP1....
Beta-2 agonist: See: Beta-agonist....
Beta-defensin: See: Defensin....
Beta-secretase: An enzyme that appears to be directly involved in the early development of Alzheimer's disease. Beta-secretase is a protease (an enzyme that catalyses the splitting of interior peptide bonds in a protein). Beta-secretase acts by trimming off a protein protruding from a brain cell. Th...