The Circulatory System Lecture Notes

The Circulatory System


Function: transports oxygen, nutrients and other substances throughout the body and removes wastes from the tissues.

The major organ of the Circulatory system is the heart.

The Heart

There are 4 chambers in the human heart; The Right & Left Atrium and the Right & Left Ventricles.

R. Atria: Oxygen poor blood returning from the body will enter the heart here  and then be pushed into the R. Ventricle.

 Oxygen poor blood that enters the R. Ventricle is pumped to the lungs where it releases carbon dioxide and picks up oxygen.

L. Atrium: Oxygenated blood returning from the lungs enters the heart here.

L. Ventricle: The thickest part of the heart pumps oxygen rich blood out to the body.

Blood Vessels


There are 3 types of blood vessels in the human body; arteries, veins & capillaries.

Arteries: carry blood AWAY from the heart.

Veins: carry blood TO the heart

Capillaries: The smallest blood vessels in the body, and is the site of gas exchange and transition between arteries & veins. (Fig. 33-5)

Draw, label and color the heart on your paper bag "person". Complete the Circulatory System Worksheet