Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «V»:
Vasovagal reaction: A reflex of the involuntary nervous system that causes the heart to slow down (bradycardia) and that, at the same time, affects the nerves to the blood vessels in the legs permitting those vessels to dilate (widen). As a result the heart puts out less blood, the blood pressure dr...
Vasovagal syncope: The temporary loss of consciousness in a particular kind of situation (situational syncope) due to a vasovagal reaction. See also: Syncope....
VATER association: A nonrandom association of birth defects.
VATER is an mnemonic in which the letters V, A, T, E, and R each stand for one or more type of malformation. The VATER association has been extended and is now called the VACTERL association. See: VACTERL association....
Vater, ampulla of
Vater, ampulla of: See: Ampulla of Vater....
Vater, papilla of
Vater, papilla of: See: Ampulla of Vater....
VBAC: Vaginal Birth After Cesarian section. Although the abbreviation
VBAC (pronounced VEE-back) does not appear in standard medical dictionaries, it is in active international use.
VBAC has waxed and may wane in popularity. For many years the mantra was "once a Caesarean, always a Caesarean" for it...
vCJD: Stands for variant Creutzfeldt-Jakob disease, a human disease thought due to the same infectious agent as bovine spongiform encephalopathy (BSE), or mad cow disease. Both the human and bovine disorders are invariably fatal brain diseases with unusually long incubation periods measured in years...
VCU: Voiding cystourethrography. Or voiding cystourethrogram....
VCUG: Voiding cystourethrography. Or voiding cystourethrogram....
VDRL test: A blood test for syphilis (VDRL stands for
Venereal Disease Research Laboratory) that detects an antibody that
is present in the bloodstream when a patient has syphilis. A
negative (nonreactive) VDRL is compatible with a person not having
syphilis, but in the early stages of the disea...
Vector: In medicine, a vector is a carrier. The best
way to understand a vector is to recall its origin as a word. Vector
is the Latin word for a "bearer."
In parasitology (the study of parasitic organisms), the vector
carries the parasitic agent. For example, in malaria a mosquito
serves as the ...
Vector, cloning: A DNA molecule originating from a virus, a plasmid (see below) or the cell of a higher organism into which another DNA fragment can be integrated without loss of the vector's (carrier's) capacity for self-replication.
Cloning vectors are used to introduce foreign DNA into host cel...
Vectrin: Brand name for minocycline....
VEGF: Vascular endothelial growth factor, a substance made by cells that stimulates the formation of new blood vessels, a process called angiogenesis. VEGF also acts as a mitogen for vascular endothelial (vessel lining) cells, stimulating these cells to divide and multiply.
VEGF is a polypeptide. I...
Vein: A blood vessel that carries blood low in oxygen
content from the body back to the heart. The deoxygenated form of
hemoglobin (deoxyhemoglobin) in venous blood makes it appear dark.
Veins are part of the afferent wing of the circulatory system which
returns blood to the heart.