2. The Circulatory System 3 ESSENTIAL COMPONENTS VESSELS TRANSPORTS THE BLOOD HEART PUMPS THE BLOOD THROUGH THE BODY BLOOD Carrier

3. Importance of the Circulatory System The circulatory System has several important functions: Carry chemical messages (hormones) throughout the body Carry nutrients and oxygen to cells Carry waste away from cells Distribute heat Maintain body fluids Maintains the immune system

4. Blood volume ( average adult )  males: 5 to 6 liters  females: 4 to 5 liters  slightly alkaline  pH (7.35–7.45)  viscosity  internal friction of whole blood is 3 times that of water

5. Components of Blood -0.1% White Blood Cells & Platelets -99.9% Red Blood Cells Average Person Has 5L

6. Components of the Blood Red Blood Cells (RBC’s) – Also known as Erythrocytes White Blood Cells (WBC’s) – Also known as leukocytes Platelets

7. Components of the Blood Red blood cells: Biconcave Structure – allows them to fit through small vessels called capillaries Do not contain a nucleus – Packed with hemoglobin which attracts & binds oxygen Hemoglobin – increases the oxygen carrying ability of the blood by 70 times (1 RBC=280 Million)

8. Hemoglobin Hemoglobin molecule: each RBC can carry up to 1 billion O2 molecules when binds with O2  bright red blood when binds with CO2  dark red blood

9. Components of the Blood White Blood Cells: Less WBC’s than RBC’s (1:700) Have a nucleus Immune system relies on WBC’s to attack viruses, bacteria or other foreign substances that may enter the body Form antibodies (used for foreign material recognition)- does not attack objects themselves-they alert WBC’s to attack

10. Components of the Blood Platelets: Similar to RBC’s, these cells contain a nucleus Move through blood until they strike any sharp object or torn tissue, then they rupture Release chemicals that create a mesh of fibres

11. Platelet Importance Red blood cells get caught in fiber mesh Creation of Blood Clots

12. Bone Marrow RBCs, WBCs and platelets are all produced in the bone marrow