Circulatory System

​Text 1

The circulatory system (also called the cardiovascular system) is formed by all the structures that move blood through the body (Figure 2.8). The circulatory system consists of the heart, blood vessels, and blood. The heart pumps the blood that the blood vessels transport to every cell in the human body. Functions of the circulatory system include the following:

• transporting oxygen and other nutrients to cells in the body

• removing carbon dioxide and other waste products

• regulating body temperature

• assisting with immune function

Heart

​text 2

The heart contains four hollow spaces called chambers. The top two chambers are called atria. The bottom two chambers are called ventricles. Valves control the direction of blood flow in the heart. Like doors that open only one way, the valves make sure blood flows in the right direction. For example, one valve makes sure that blood flows from an atrium to a ventricle. It will not let blood flow from a ventricle to an atrium. Other valves make sure that blood leaving a ventricle does not flow backward into the ventricle.

​Blood Circulation Text 3

Oxygen-poor blood flows from around the body into the right atrium, which passes this blood into the right ventricle. The right ventricle pumps oxygen-poor blood out of the heart to the lungs, where this blood obtains oxygen

​Blood Circulation Text 4

Then oxygen-rich blood is returned from the lungs into the left atrium of the heart, which passes blood into the left ventricle. Finally, the left ventricle pumps oxygen-rich blood into the aorta. The oxygen-rich blood is then pumped around the body. After oxygen is used up, the oxygen-rich blood becomes oxygen-poor blood and flows back into the right atrium. The process then begins again.

The oxygen-poor blood (shown in blue) enters the heart where it is sent to the lungs and returns as oxygen-rich blood (shown in red) to the heart. From there, the blood is sent to the rest of the body.

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​Blood Vessels

Blood vessels are an extensive network of pipes that carry blood throughout the entire body
There are three types of blood vessels. These vessels are the arteries, capillaries, and veins.

Arteries deliver oxygen-rich blood to capillaries. Blood flows through capillaries to deliver oxygen to body tissues. Once oxygen has been taken out of the blood, the blood returns to the heart through veins.

Vocabulary Words

​To be done in your notebook

Arteries
Capillaries
Veins
Plasma
Red blood cell
White blood cell
Platelets

​Different types of blood and which blood type it can donate to.

​The basic parts of blood include plasma, which is the liquid part, and red blood cells, white blood cells, and platelets, which are all solid in form