Instructor: Aniko Szucs

This is an introduction to your body’s circulatory system. It is also called your cardiovascular system. Your heart , blood, and blood vessels make up this system (group of similar tissues that work together to perform a function.)


Think about it:

What functions do you think
your circulatory system performs?

Watch this

Click Here To See Movie


to see if you were right!


1.     Read the following three questions.

·        What three structural elements make up the circulatory system?

·        If your heart stopped pumping, how long could you expect to live?

·        What carries blood to the heart? What carries it away?

2.     Copy and paste them to Microsoft Word.

3.     Read the article and then answer the questions in Microsoft Word.  (Use complete sentences)

4.     Print out your answers and turn them in. Don’t forget to add your name!



This article was written by John F. Setaro, M.D. It explains the components of the circulatory system.

The heart, blood, and blood vessels are the three structural elements that make up the circulatory system. The heart is the engine of the circulatory system. It is divided into four chambers: the right atrium, the right ventricle, the left atrium, and the left ventricle. The walls of these chambers are made of a special muscle called myocardium, which contracts continuously and rhythmically to pump blood. The pumping action of the heart occurs in two stages for each heart beat: diastole, when the heart is at rest; and systole, when the heart contracts to pump deoxygenated blood toward the lungs and oxygenated blood to the body. During each heartbeat, typically about 60 to 90 ml (about 2 to 3 oz) of blood are pumped out of the heart. If the heart stops pumping, death usually occurs within four to five minutes.

Blood consists of three types of cells: oxygen-bearing red blood cells, disease-fighting white blood cells, and blood-clotting platelets, all of which are carried through blood vessels in a liquid called plasma. Plasma is yellowish and consists of water, salts, proteins, vitamins, minerals, hormones, dissolved gases, and fats.

Three types of blood vessels form a complex network of tubes throughout the body. Arteries carry blood away from the heart, and veins carry it toward the heart. Capillaries are the tiny links between the arteries and the veins where oxygen and nutrients diffuse to body tissues… Blood vessels expand during exercise to meet the increased demand for blood and to cool the body. Blood vessels contract after an injury to reduce bleeding and also to conserve body heat.

Arteries have thicker walls than veins to withstand the pressure of blood being pumped from the heart. Blood in the veins is at a lower pressure, so veins have one-way valves to prevent blood from flowing backwards away from the heart. Capillaries, the smallest of blood vessels, are only visible by microscope—ten capillaries lying side by side are barely as thick as a human hair. If all the arteries, veins, and capillaries in the human body were placed end to end, the total length would equal more than 100,000 km (more than 60,000 mi)—they could stretch around the earth nearly two and a half times.


If you have time, you may explore the heart .   Click your mouse to see the name of the part you are looking at.