Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «V»:
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Vascular endothelial growth factor (VEGF)
Vascular endothelial growth factor (VEGF): A substance made by cells that stimulates new blood vessel formation, a mitogen for vascular endothelial (vessel lining) cells.
VEGF is a polypeptide structurally related to platelet-derived growth factor (PDGF). The gene for VEGF is on chromosome 6p12....
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Vascular headache
Vascular headache:
A group of headaches felt to involve abnormal sensitivity of the blood vessels (arteries) in the brain to various triggers which results in rapid changes in the artery size due to spasm (constriction). Other arteries in the brain and scalp then open (dilate), and throbbing pain is...
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Vascular hemophilia
Vascular hemophilia: See: Von Willebrand disease....
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Vasculitis
Vasculitis: Plural: vasculitides. A general term for a group of diseases that feature inflammation of the blood vessels. Each of these diseases is defined by characteristic distributions of blood vessel involvement, patterns of organ involvement, and laboratory test abnormalities. The causes of thes...
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Vasculitis, allergic
Vasculitis, allergic: A disease (also more commonly called the Churg-Straus syndrome) characterized by inflammation of the blood vessels in persons with a history of asthma or allergy.
The symptoms of the Churg-Strauss syndrome include fatigue, weight loss, inflammation of the nasal passages, numbn...
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Vasculitis, retinal
Vasculitis, retinal: The retina is the portion of the eye
that contains the nerves of sensation that perceive light. It is also
filled with tiny blood vessels. Vasculitis of the eye is typically
the result of inflammation of the tiny blood vessels of the retina.
This form of vasculitis is refe...
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Vasectomy
Vasectomy: A vasectomy is a surgical procedure designed to make a man sterile by cutting or blocking both the right and left vas deferens, the tubes through which sperm pass into the ejaculate....
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Vasoconstriction
Vasoconstriction: Narrowing of the blood vessels
resulting from contracting of the muscular wall of the vessels. The opposite of
vasodilation....
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Vasodepressor syncope
Vasodepressor syncope: The temporary loss of consciousness in a particular kind of situation. (Syncope is temporary loss of consciousness or, in plain English, fainting). The situations that trigger this reaction are diverse and include having blood drawn, straining while urinating or defecating or...
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Vasodilation
Vasodilation: Widening of blood vessels resulting from
relaxation of the muscular wall of the vessels. What widens is actually the diameter of
the interior (the lumen) of the vessel. The opposite of vasoconstriction....
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Vasodilators
Vasodilators: Agents that act as blood vessel dilators
(vasodilators) and open vessels by relaxing their muscular walls. For example,
nitroglycerin is a vasodilator. So are the ACE (angiotensin converting enzyme) inhibitors.
...
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Vasomotor
Vasomotor: Relating to the nerves and muscles
that cause the blood vessels
to
constrict or dilate....
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Vasomotor rhinitis
Vasomotor rhinitis:
Inflammation of the nose (rhinitis) due to abnormal neuronal (nerve) control of the blood
vessels in the nose. Vasomotor rhinitis is not allergic rhinitis....
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Vasopressin
Vasopressin: A relatively small (peptide)
molecule that is released by the
pituitary gland at the base of the brain after being made
nearby (in the
hypothalamus). Vasopressin has an antidiuretic action that
prevents the
production of dilute urine (and so is antidiuretic). A
syndrome of
inapprop...
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Vasovagal attack
Vasovagal attack: See: Vasovagal reaction....
