48 Introduction: The Cardiovascular System

Heather Ketchum and Eric Bright

The cardiovascular system can be divided into three sections, the heart, the blood vessels, and the blood.

The Heart4

Human Heart

This photo shows a human heart.This artist’s conception of the human heart suggests a powerful engine—not inappropriate for a muscular pump that keeps the body continually supplied with blood. (credit: Patrick J. Lynch)

There is no single better word to describe the function of the heart other than “pump,” since its contraction develops the pressure that ejects blood into the major vessels: the aorta and pulmonary trunk. From these vessels, the blood is distributed to the remainder of the body. Although the connotation of the term “pump” suggests a mechanical device made of steel and plastic, the anatomical structure is a living, sophisticated muscle. As you read this chapter, try to keep these twin concepts in mind: pump and muscle.

Although the term “heart” is an English word, cardiac (heart-related) terminology can be traced back to the Latin term, “kardia.” Cardiology is the study of the heart, and cardiologists are the physicians who deal primarily with the heart.

The Blood Vessels4

Blood Vessels

This photo shows a forearm with the veins bulging.While most blood vessels are located deep from the surface and are not visible, the superficial veins of the upper limb provide an indication of the extent, prominence, and importance of these structures to the body. (credit: Colin Davis)


The blood vessels make up the vascular components of the cardiovascular system. The vessels that transport blood throughout the body and provide the physical site where gases, nutrients, and other substances are exchanged with body cells. When vessel functioning is reduced, blood-borne substances do not circulate effectively throughout the body. As a result, tissue injury occurs, metabolism is impaired, and the functions of every bodily system are threatened.

The Blood4

Blood Cells

This photo shows a red blood cell and a white blood cell.A single drop of blood contains millions of red blood cells, white blood cells, and platelets. One of each type is shown here, isolated from a scanning electron micrograph.


Single-celled organisms do not need blood, but humans are NOT single-cell organisms. Humans are made up of trillions of cells that require nutrients and need to have waste products removed from our bodies. The blood is the medium of transport for these nutrients and to facilitate waste removal from our cells. The heart pumps blood throughout the body in a network of blood vessels.

The heart, blood vessels, and blood that make up our cardiovascular system does not act in isolation, this complex system works in unison with other body systems to ensure appropriate functioning. Next up, we’ll take a look at the respiratory system which is essential for creating the efficient functioning of the cardiorespiratory system to help facilitate movement, physical activity, exercise, and most importantly: LIFE.

Heather Ketchum & Eric Bright, OU Human Physiology Textbook. OpenStax CNX. Jun 18, 2015. Download for free at http://cnx.org/contents/e4f804ec-103f-4157-92e1-71eed7aa8584@1


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Introduction to Exercise Science for Fitness Professionals Copyright © 2021 by Heather Ketchum and Eric Bright is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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