Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «A»:
Accessory neuropathy: Disease of the accessory nerve which is the eleventh cranial nerve. The accessory nerve supplies the sternocleidomastoid and trapezius muscles. The sternocleidomastoid muscle is in the front of the neck and turns the head. The trapezius muscle moves the scapula (the wingbone),...
Accessory placenta: An extra placenta
separate from the main placenta. Also called a succenturiate or
supernumerary placenta. The placenta is the organ joining the mother
and fetus, the organ that permits the provision of oxygen and
nutrients to the fetus and the release of carbon dioxide and wa...
Acclimatization to altitude
Acclimatization to altitude: The main cause of altitude sickness is going too high too fast. Given time, the body can adapt to the decrease in oxygen concentration at a specific altitude, process known as acclimatization.
To acclimatize, a number of changes take place in the body occur to allow it ...
Accommodation: In medicine, the ability of the eye to change its focus from distant to near objects (and vice versa). This process is achieved by the lens changing its shape.
Accommodation is the adjustment of the optics of the eye to keep an object in focus on the retina as its distance from the ...
Accoucheur: French for a male obstetrician,
a physician skilled in the art and science of managing pregnancy,
labor and the puerperium (the time after delivery)....
Accoucheuse: French for a woman who is an
obstetrician (a physician skilled in the art and science of managing
pregnancy, labor and the time after delivery) or a midwife (today a
non-physician trained to assist a woman during childbirth). The
ending "-euse" is feminine and indicates that the ac...
ACE (angiotensin converting enzyme)
ACE (angiotensin converting enzyme): The
angiotensins are peptides (substances smaller than proteins) that act
as vasoconstricting agents (causing blood vessels to narrow).
Narrowing the diameter of the blood vessels sends up the blood
ACE converts angiotensin to its activated form (...
ACE inhibitors: A drug that inhibits ACE (angiotensin
converting enzyme) which is important to the formation of
angiotensin II. Angiotensin II causes arteries in the body to
constrict and thereby raises the blood pressure. ACE inhibitors lower
the blood pressure by inhibiting the
formation of a...
ACE2 (angiotensin converting enzyme 2)
ACE2 (angiotensin converting enzyme 2): An essential regulator of heart function. Also may be involved in the embryonic development of the heart. The ACE2 gene has been mapped to the X chromosome (band Xp22)....
ACEI: ACE inhibitor....
Acellular: Not made up of cells or divided into cells. Or lacking intact cells as, for example, an acellular vaccine which may contain cellular material but not complete cells....
Acellular vaccine: A vaccine that may contain cellular material but does not contain complete cells....
Acentric chromosome: A fragment of a
chromosome (one of the microscopically visible carriers of the
genetic material DNA) that is lacking a centromere (the "waist" of
the chromosome essential for the division and the retention of the
chromosome in the cell) and so is lost when the cell divides....
Aceruloplasminemia: A genetic disorder in which there is absence of the protein ceruloplasmin from blood and accumulation of iron in the pancreas, liver and brain, causing diabetes and progressive neurodegeneration with the tremors and gait abnormalities characteristic of Parkinson disease.
Acetabular: Pertaining to the
acetabulum, the cup-shaped socket of the hip joint which is a key
feature of the pelvis. The head (upper end) of the femur
(the thighbone) fits into the acetabulum and articulates
with it, forming a ball-and-socket joint.The
acetabulum is not just cup-shaped. The w...