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 coughing. The reaction also can be due to the emotional stress of fear or pain.
In these situations, people subject to vasodepressor syncope often become pale and feel nauseated, sweaty, and weak just before they lose consciousness.
Vasodepressor syncope is caused a reflex of the involuntary nervous system called the vasovagal reaction. The vasovagal reaction leads the heart to slow down (bradycardia) and, at the same time, it leads the nerves to the blood vessels in the legs to permit those vessels to dilate (widen). The result is that the heart puts out less blood, the blood pressure drops, and what blood is circulating tends to go into the legs rather than to the head. The brain is deprived of oxygen and the fainting episode occurs.
A vasovagal reaction is also called a vasovagal attack. And vasodepressor syncope is also called situational syncope, vasovagal syncope, and Gower syndrome.
Widening of blood vessels that results from relaxation of the muscular walls of the vessels. What widens in vasodilation is actually the diameter of the interior (lumen) of the vessel. The opposite of vasodilation is vasoconstriction.
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.
Relating to the nerves and muscles that cause blood vessels to constrict or dilate.
- Vasomotor rhinitis
Inflammation of the nose (rhinitis) due to abnormal nerve control of the blood vessels in the nose. Vasomotor rhinitis is not allergic rhinitis. Decongestant medications are used to temporarily reduce swelling of sinus and nasal tissues leading to an improvement of breathing and a decrease in obstruction.
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 inappropriate secretion of vasopressin which results in the inability to put […]