Circulatory System: Blood!7SCIENCE Mon. Jan. 17

What is blood?• Blood makes up around 8% of

your body weight (5L!)• Consists of:– Cells and liquid

• Blood has many parts:– Plasma

• Liquid part of blood, mostly water

– Red blood cells• Has hemoglobin, important for carrying oxygen and carbon dioxide

– White blood cells• Fight bacteria and other foreign substances

– Platelets• Pieces of cells that help form blood clots (stop bleeding)

Why is it important to study?

Has many functions:• Carries oxygen from your lungs to

the rest of the body• Removes carbon dioxide from body cells and carries it

to your lungs to beremoved

• Carries wastes from your kidneys

• Transports nutrients• Fights infections

Blood Types

Blood Transfusion Possibilities

Type Can RECEIVE Can DONATE to

A O, A A, AB

B O, B B, AB

AB O, A, B, AB AB

O O O, A, B, AB

• Sometimes you may need to receive blood– E.g. surgery, accident

• This is called a blood transfusion– Must be the right type!– If it is the WRONG type, the blood cells will clump together and

clog the blood vessel

4 Blood Types: A,B, AB and O

Diseases of the blood• Anemia

– Too few red blood cells ortoo little hemoglobin to carry oxygen

– Cells cannot get enough oxygen

• Leukemia– Too many white blood cells are

produced but they cannot fight infections

– Treatments: Blood transfusions, bone marrow transplants, chemotherapy and radiation may be used

• Why is blood called the ‘tissue of life’?