Medical Definitions - A
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Acidosis - the accumulation of acid and hydrogen ions or depletion of the alkaline reserve (bicarbonate content) in the blood and body tissues, decreasing the pH.
ACT - activated clotting time; a test to see how long it takes blood to clot.
AFI - amniotic fluid index; a measure of the amount of amniotic fluid surrounding a fetus.
AFP test - Alpha Fetoprotein; a blood test given to a pregnant woman between 16 and 20 weeks gestation to test for fetal abnormalities. There are instances of false positives and not every problem is detected with this test.
Agenesis - when a body part does not develop correctly or at all.
Albumin - a main protein found in human blood.
Alkalosis - a pathologic condition due to accumulation of base in, or loss of acid from, the body.
Alveolar epithelium - the tissue that covers the external surface of the alveoli.
Alveoli - the plural of alveolus; the alveoli are tiny air sacs within the lungs where the exchange of oxygen and carbon dioxide takes place.
AMBU bag - a flexible reservoir bag connected by tubing and a non-rebreathing valve to a face mask or endotracheal tube and used for artificial ventilation. It is self-inflating with room air or from an oxygen source.
Amnio - shortened form of amniocentesis.
Amniocentesis - a pre-natal test where amniotic fluid is extracted from the amniotic sac surrounding the fetus and tested for chromosomal abnormalities, lung development, etc.
Analgesic - a drug that relieves pain.
Anasarca - extensive subcutaneous edema; an accumulation of serous fluid in various tissues and cavities of the body.
Aniridia - congenital absence of the iris.
Antibiotic - a drug used to treat infections caused by bacteria and other microorganisms.
Anticoagulant - anti-clotting; blood thinner.
Anuria - the absence of urine formation.
Arachnoid - One of the membranes that sheathes the spinal cord and brain; the arachnoid is the second-layer membrane.
Arterial blood gas (ABG) - The sampling of the blood levels of oxygen and carbon dioxide within the arteries, as opposed to the levels of oxygen and carbon dioxide in venous blood. Typically, the acidity, or pH, of the blood is measured simultaneously in ABG sampling.
Artery - a blood vessel that carries blood away from the heart to the body's organs.
Atelectasis - a collapse of lung tissue affecting part or all of one lung. This condition prevents normal oxygen absoption to healthy tissues.
Ativan - brand name of the drug Lorazepam; enhances the effect of a neurotransmitter, the nerves in the brain used to send messages to one another.
Autopsy - also known as a necropsy; a postmortem examination.