The New Childrens Encyclopedia

THE HUMAN BODY

WHAT BLOOD DOESBlood delivers oxygen, water, and nutrients to your body’s organs and takes away waste carbon dioxide. It also takes white blood cells to where they are needed, to fight infection, and clots to stop bleeding and form a seal to repair damage if you cut yourself. There’s more? Yes! It allows you to maintain a steady body temperature.

The femoral

artery

supplies

blood to the

thigh.

BLOOD CIRCULATION

Blood is pumped around the body by the heart, which is the hardest working muscle in the body. It follows a figure-eight route. The shorter loop (green arrows) takes blood from the heart to the lungs and back. The longer loop (yellow arrows) takes blood to other parts of the body, then returns it to the heart.

It takes a blood cell about one minute to circulate your body.The heart pumps blood along a network of blood vessels.

An adult body contains about 10½ pints (5 liters) of blood.

Blood f lowThink of your arteries and veins as a road network for your body. Blood flows through this network, just as trucks move along highways, carrying and delivering the essentials that your cells need and removing waste products. Your arteries and veins are your body’s transportation, or circulatory, system.

BLOOD GROUPS

Blood is not all the same. There are four different groups, and each group is given a letter. You might be type A, B, AB, or O. AB is the rarest. If a person has to have a blood transfusion, they have to receive the same blood group.

This represents the head and upper body.

This represents the digestive system.

Left lung

This represents the lower body.

Right lung

Heart

This represents the liver.