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

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

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

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

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

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)

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

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

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

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

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