Section I. DEFINITIONS
Visualize a man walking down a hallway. He pauses at the foot of a stairway.
From his pocket, he takes a small bottle containing some very small white tablets and
he places one of these tablets under his tongue. After waiting a few seconds, he
proceeds up the stairs. What was this scene? It was a man preparing his body--
especially his heart--for the extra work required for walking up the stairs. This man,
suffering from a condition called angina pectoris, used one of the vasodilators that will
be discussed in this subcourse lesson. Without this drug, he would be unable to
perform many of the energy expending tasks required for everyday life. In this lesson,
you will be given the opportunity to broaden your background in some cardiovascular
diseases as well as learn more about various vasodilators.
4-2. IMPORTANT TERMS AND THEIR DEFINITIONS
You have already been introduced to some of the terms below in another lesson
in this subcourse. Some of the terms below might be new to you. In any event, each
term applies to vasodilator agents.
a. Vasodilator. A vasodilator is a drug that dilates blood vessels with a
resultant increase in blood flow.
b. Orthostatic Hypotension. Orthostatic hypotension is a condition
characterized by fainting or dizziness because of inadequate blood supply to the brain
because the blood has been pooled elsewhere in the body. Vasodilator agents may
cause this condition. You may have experienced this condition before. Have you ever
arisen quickly from a lying position to find that you are light-headed and dizzy? This is
c. Angina Pectoris. Angina pectoris is a condition manifested by excruciating
chest pain sometimes radiating down the left arm. The pain probably arises from
ischemia (lack of oxygen) in the heart caused by the increased demand for or
decreased supply of oxygen.
d. Arteriosclerosis. Arteriosclerosis is characterized by thickening, hardening,
and loss of elasticity of the walls of blood vessels.