1. Blood and Lymphatic System

2. Functions of Blood Carries oxygen from lungs to body cells Carries carbon dioxide from body cells to lungs Carries waste products from cells to kidneys Transport nutrients to cells Fights infections and heal wounds

3. Parts of blood Plasma  liquid part of blood – mostly water – Nutrients, minerals, oxygen dissolved in plasma – Carries waste from cells Red blood cells  supply body with oxygen – Contain hemoglobin, a chemical that carries oxygen and carbon dioxide – Life span is 120 days (rapidly replaced)

4. Parts of Blood White blood cells  fight bacteria and viruses – Body reacts to invaders by increasing WBC – WBC enter infected tissue, destroy bacterial/viral invaders, absorb dead cells – Life span a few days to many months Platelets  irregularly shaped cell fragments that help clot blood – Release chemicals that form filaments of fibrin – Life span 5-9 days

6. Blood Clotting Platelets and clotting factors plug up wound – Platelets stick to wound and release chemicals – Clotting factors carry out chemical reactions – Threadlike fibers called fibrin form sticky net Net traps blood cells and plasma, forming clot – Skin cells begin repair process

7. Blood Types A, B, AB, O Based on antigens – Chemical ID tags on blood – Type O has no antigens so can donate to everyone Based on antibodies – Proteins identify substances that don’t belong in body and destroy them – AB has no antibodies so can receive from anyone Based on Rh factor – People who lack Rh factor (negative type), – Have Rh factor are positive (like being O+) – If lack Rh but receive Rh positive blood, body will produce antibodies against blood which can cause blood clots.

8. Blood Disease Anemia  affects red blood cells – Body tissues don’t get enough oxygen and are unable to carry on usual activities – Causes include loss of large amount of blood, diet lacking iron, or heredity Leukemia  affects white blood cells – WBC made in excessive numbers, but are immature and don’t fight infection well – Immature cells fill up bone marrow and crowd out normal cells

9. Lymphatic System Collects tissue fluid and returns it to blood Lymph  tissue fluid that has diffused into lymphatic capillaries – Contains water and dissolved substances – Contains lymphocytes, a type of WBC that helps body defend itself – Carried through lymphatic capillaries and vessels to large veins near heart – Moved by muscle contractions – Has valves to keep lymph from flowing backward

10. Lymphatic Organs Lymph nodes  bean shaped organs of varying size found throughout body that filter microorganisms and foreign material from lymphocytes Tonsils  protect body from harmful microorganisms entering from mouth/throat Thymus  makes lymphocytes Spleen  filters blood by removing damaged red blood cells from blood, takes up and destroys bacteria and other invaders of body

11. Lymphocytes The HIV virus attacks lymphocytes called helper T-cells