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 cantaloupes and apricots. Excessive carotene in the diet can color the skin yellow, a condition called carotenemia. Carotenemia is sometimes seen in infants fed too many mashed carrots and is a reversible condition. Beta carotene supplements have been found not to reduce the risks for cancer or heart disease.
- 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 important because they make insulin. Degeneration […]
- Beta cell
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. Degeneration of the beta […]
- Beta error
Beta error: The statistical error (said to be ‘of the second kind,’ or type II) that is made in testing when it is concluded that something is negative when it really is positive. Also known as false negative.
- Beta particle
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 the amount received. They also […]
Beta-agonist: A bronchodilator medicine that opens the airways by relaxing the muscles around the airways that may tighten during an asthma attack or in COPD (chronic obstructive pulmonary disease). Beta-agonists can be administered by inhalers or orally. They are called “agonists” because they activate the beta-2 receptor on the muscles surrounding the airways. Activation of […]