dizziness during hyperventilation is due to a decrease in cerebral blood flow. The decreased blood flow is caused by
a. vasodilation
b. decreased stroke volume
c.vasoconstriction
d. decreased respriation
vaso- refers to blood vessels
http://128.240.24.212/cgi-bin/omd?vaso-
http://www.answers.com/constrict
and
http://www.answers.com/dilate
Which do you think it is?
The correct answer is c. vasoconstriction. Dizziness during hyperventilation is primarily caused by a decrease in cerebral blood flow, which is the result of vasoconstriction.
To understand how to arrive at this answer, we need to examine the process of hyperventilation. During hyperventilation, a person breathes in excess oxygen and exhales excessive amounts of carbon dioxide. This leads to a condition called respiratory alkalosis, where the blood becomes more alkaline due to a decrease in carbon dioxide levels.
In response to respiratory alkalosis, the body tries to compensate by constricting blood vessels, including those in the brain, which is known as vasoconstriction. This is intended to reduce the blood flow to the brain and try to normalize the alkaline state. However, excessive vasoconstriction can lead to a decrease in cerebral blood flow, resulting in symptoms like dizziness, lightheadedness, and even fainting.
Therefore, the correct answer is c. vasoconstriction, as it is the main reason for decreased cerebral blood flow and subsequent dizziness during hyperventilation.