Page 157 - 84 human physiolofy part-1

The Cardiovascular System

learn and come to respect the greatness of this blood pumping machine we all call the heart.

Stroke

Cerebrovascular disease are those that affect blood vessels in the brain and happen to be the third
cause of death in the United States only behind heart disease and cancer. Stroke (also called
cerebrovascular accident or CVR) is a cerebrovascular disorder caused by a sudden decrease or
stoppage of blood flow to a part of the brain. Decreased blood flow also known as ischemia is
dangerous to any tissue but brain tissue is even more vulnerable, mainly due to the high rate of its
metabolic reactions. In fact if you stopped blood flow for no more than three minutes it may be
sufficient enough to cause death of most brain cells. For this reason a stroke can kill people within
minutes or leave them with severe brain damage.

Strokes may be classified as either occlusive or hemorrhagic and may happen either in the interior
of the brain or on its surface. In a occlusive stroke blood flow through a vessel is blocked. In a
hemorrhagic stroke a blood vessel ruptures causing a hemorrhage.

Summary

As with all of the body systems, the cardiovascular system plays a part in maintaining homeostasis.
The nervous system regulates the functioning of the heart based on what the heart is supposed to do.
The pumping of the heart maintains normal blood pressure and proper oxygenation of tissues. The
vascular system forms passageways for the blood, but they aren't simply just a pipeline system. The
vessels are not passive tubes, but rather active contributors to homeostasis. The arteries and veins help
maintain blood pressure, and the capillaries provide sites for the necessary exchanges of materials
between the blood and the tissues.

Review Questions

1. This conducts electricity like nerves

A) Epicardium
B) Pericardium
C) Myocardium
D) Subvalaular Apparatus
E) None of these, only nerves conduct electricity

2. This carries the most blood at any given time in the body

A) Veins
B) Capillary Beds
C) Veins
D) Aorta
E) Vena Cava

3. The following contract together to pump blood

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