Medical terms - Letter A (page 24) | MedicalVocabulary.org

APLS (antiphospholipid antibody syndrome)

Antiphospholipid antibody syndrome): An immune disorder characterized by the presence of abnormal antibodies in the blood associated with abnormal blood clotting, migraine headaches, recurrent pregnancy losses (repeat…
APM1

Adipose most abundant gene transcript 1. (AdiPose Most abundant gene transcript 1 = APM1.) The APM1 gene encodes the hormone adiponectin
Apnea

An apnea is a period of time during which breathing stops or is markedly reduced. There are two types of apneas, the more common obstructive sleep apnea and the less common central sleep apnea. Apneas usually occur…
Apnea, central sleep

Sleep (CSA): Sleep apnea is a breathing disorder characterized by brief interruptions of breathing during sleep. It owes its name to a Greek word, apnea, meaning 'want of breath.' There are two types of sleep apnea…
Apnea, obstructive sleep

Sleep apnea is a breathing disorder characterized by brief interruptions of breathing during sleep. It owes its name to a Greek word, apnea, meaning 'want of breath.' There are two types of sleep apnea: central and…
APO-1

See: FAS gene
APOA-I

Apolipoprotein A-I
ApoA-I Milano

A variant of apolipoprotein A-I identified in about 40 inhabitants of Limone sul Garde, a small town in rural North Italy, who had extraordinarily low HDL levels, levels so low that they were off the scale. Because HDL…
APOBEC3G

A human protein that interferes with the replication of HIV by incorporating itself into virus particles and damaging the genetic material of the virus. The viral protein Vif can halt this process in two ways: (1) by…
ApoE

Abbreviation for apolipoprotein E, a gene that codes for a protein component of lipoproteins (complexes of fat + protein) that are normal constituents of blood plasma -- namely, chylomicrons, HDL (high density…
Apolipoprotein A-I

APOA-I. The major protein component of HDL (high density lipoprotein) and a relatively abundant plasma protein. APOA-I is instrumental in promoting the transfer of cholesterol into the liver where it is metabolized and…
Apolipoprotein E

A type of lipoprotein (a protein connected to a fat). Apolipoprotein E is abbreviated ApoE and the gene that encodes it is known as APOE. APOE is located on chromosome 19 in band 19q13.2. Lipoproteins are responsible…
Apollo

In Greek mythology, often considered to be a god of healing. In stories such as The Iliad, Apollo is depicted as the bringer and reliever of plagues
Apopain

See: Caspase 3
Apophenia

In psychology, the perception of connections and meaningfulness in unrelated things. Apophenia can be a normal phenomenon or an abnormal one, as in paranoid schizophrenia when the patient sees ominous patterns where…
Apophysitis calcaneus

Also called Sever's condition, this disorder is due to inflammation of the growth plate of the calcaneus, the bone at the back of the heel. The inflammation is at the point where the Achilles tendon attaches. It occurs…
Apoplexy

A venerable term for a stroke, a cerebrovascular accident (CVA), often associated with loss of consciousness and paralysis of various parts of the body. The word 'apoplexy' comes from the Greek 'apoplexia' meaning a…
Apoptosis

A form of cell death in which a programmed sequence of events leads to the elimination of cells without releasing harmful substances into the surrounding area. Apoptosis plays a crucial role in developing and…
Appendectomy

Appendectomy: Removal by surgery of the appendix, the small worm-like appendage of the colon (the large bowel). An appendectomy is performed because of probable appendicitis, inflammation of the wall of the appendix…
Appendiceal

Relating to the appendix. As, for example, an appendiceal abscess. Perforation of the appendix can lead to a periappendiceal abscess or diffuse peritonitis (infection of the entire lining of the abdomen and the pelvis)
Appendiceal cancer

See: Appendix cancer
Appendiceal perforation

Rupture of appendix
Appendiceal rupture

Rupture of appendix
Appendicitis

Appendicitis: Inflammation of the appendix, the small worm-like projection from the first part of the colon. Appendicitis usually involves infection of the appendix by bacteria that invade it and infect the wall of the…
Appendix

A small outpouching from the beginning of the large intestine (the ascending colon). Formally called the vermiform appendix because it was thought to be wormlike. See also: Appendicitis; Appendix cancer.
Appendix cancer

A malignancy of the appendix, accounting for about 1 in 200 of all gastrointestinal malignancies. Although unusual, cancer of the appendix can range in type. The most common type of appendiceal cancer is carcinoid tumor…
Appendix epididymis

A small cystic projection from the surface of the epididymis which represents a remnant the embryologic mesonephros. The epididymis is a structure within the scrotum attached to the backside of the testis. The…
Appendix epiploica

A finger-like projection of fat attached to the colon.
Appendix perforation

Rupture of appendix
Appendix rupture

Rupture of appendix
Appendix testis

A small solid projection of tissue on the outer surface of the testis which is a remnant of the embryologic mullerian duct.
Apposition

The word 'apposition' has several senses including the act of adding or accretion and also the putting of things in juxtaposition, or side by side. Growth by apposition is a mode of growth that is characteristic of many…
Approved drug

A medication approved for marketing. In the US, the Food and Drug Administration (FDA) must approve a substance as a drug before it can be marketed. The approval process involves several steps including pre-clinical…
Apraxia

The inability to execute a voluntary motor movement despite being able to demonstrate normal muscle function. Apraxia is not related to a lack of understanding or to any kind of physical paralysis but is caused by a…
Apraxia of speech

A severe speech disorder characterized by inability to speak, or a severe struggle to speak clearly. Apraxia of speech occurs when the oral- motor muscles do not or cannot obey commands from the brain, or when the brain…
APS (autoimmune polyglandular syndrome)

A genetic autoimmune disease with an extraordinary array of clinical features but characterized most often by at least 2 of the following 3 findings: hypoparathyroidism -- underfunction of the parathyroid glands which…
APT1

See: FAS gene
AQP

Aquaporin
Aquaphobia

An abnormal and persistent fear of water. Sufferers from aquaphobia experience anxiety even though they realize the water in an ocean, a river, a lake, a creek or even a bathtub may pose no imminent threat. They…
Aquaporin

A water channel. Aquaporins form pores in the membranes of cells and selectively conduct water molecules through the membrane, while preventing the passage of ions (such as sodium and potassium) and other small…
Aqueduct

A channel for the passage of fluid.
Aqueduct of Sylvius

A canal that communicates between the third and fourth ventricles in a system of four communicating cavities within the brain that are continuous with the central canal of the spinal cord. The four ventricles consist of…
Aqueduct of the midbrain

A canal that communicates between the third and fourth ventricles in a system of four communicating cavities within the brain that are continuous with the central canal of the spinal cord. The four ventricles consist of…
Aqueous humor

In medicine, humor refers to a fluid (or semifluid) substance. Thus, the aqueous humor is the fluid normally present in the front and rear chambers of the eye. It is a clear, watery fluid that flows between and…
Arabidopsis thaliana

A plant belonging to the mustard family. See also: Arabidopsis thaliana genome
Arabidopsis thaliana genome

All of the genetic information contained in Arabidopsis thaliana, a plant belonging to the mustard family. The genomes of particular nonhuman organisms such as Arabidopsis have been studied for a number of reasons…
Arachidonate 5-lipoxygenase activating protein

ALOX5AP. See: FLAP
Arachidonate 5-lipoxygenase-activating protein

ALOX5AP. See: FLAP
Arachnodactyly

Long spider-like fingers and toes, a frequent finding in Marfan syndrome, a heritable disorder of connective tissue. 'Arachnodactyly' is derived from the Greek 'arachne' (spider) and 'daktylos' (finger). The Greek word…
Arachnoiditis

Arachnoiditis: Inflammation of the middle layer of membranes covering the brain and spinal cord. Arachnoiditis can occur as a complication of procedures such as myelograms, spinal operations, epidural steroid…