4.1 The body's transport system

​Objectives

Explain the functions of the cardiovascular

system.

Describe the function and structure of the heart.

Sequence the path blood follows through the

cardiovascular system.

• The cardiovascular system

  delivers blood to all parts of the body, carrying necessary substances to cells and carrying waste materials away from cells.

• Blood contains cells that fight disease, as well.

What Is the Role of the Heart?

Without your heart your blood would not go anywhere. The heart is a hollow, muscular organ. The heart pumps blood to the body through blood vessels.

The Heart’s Structure

The heart has a right side and left

side that are completely separated by a wall of tissue called the septum. Each side has two chambers. Each upper chamber, called an atrium (AY tree um; plural atria), receives blood that comes into the heart. Each lower chamber, called a ventricle, pumps blood out of the heart. The pacemaker, a group of cells in the right atrium, sends out signals that make the heart muscle contract. The signals regulate heart rate.

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