What is the circulatory system? Lesson 12 What is the circulatory system?

Can you imagine being a messenger that makes trillions of stops in just 30 seconds???? Your blood does! Blood is an important body messenger. It is on the move day and night.

In just 30 seconds, your blood moves or circulates through your whole body. It reaches out to all of your trillions of cells. Blood transports (carries) to the cells all the things it needs. What do your cells need?

Cells need things like: oxygen digested foods The cells absorb or take in these materials.

The blood is also your body’s trash collectors. What type of things are made in the cells that need to be taken out with the trash? heat carbon dioxide extra water

The blood picks up these waste materials from the cells and takes them to places that get them out of the body. (we will talk about that later in the year)

Blood is pumped throughout the body by the heart Blood is pumped throughout the body by the heart. It flows through a closed system of tubes, called blood vessels. Your body has three types of blood vessels.

Arteries: -carry blood away from the heart -carry the materials the cells need -except the arteries going to the lungs carry blood rich in oxygen and nutrients

Veins: -carry blood from the body back to the heart -except the veins coming from the lungs, veins carry blood with dissolved waste products

Capillaries: -connect arteries and veins -are microscopic -most of the blood vessels in your body are capillaries

The heart, blood vessels, and blood make up your circulatory system. Circulation, or transport, is a vital function. Life can not go on without it.