1. Thrombocytes (Platelets) & Plasma

2. Structure Fragments of giant cells (megakaryocytes) (each produces b/t 5-10,000 platelets) Enter circulation – live for approx. 1 wk.; destroyed by spleen & liver Disk-shaped, w/o nucleus ½ the size of an RBC

3. Function Normal platelet count – 130,000-360,000/mm³ Stem blood flow (hemo- stasis) 2 ways: 1. 2.

4. Platelet Plug Formation 1. B.V.damaged 2. Some blood escapes 3. Platelets adhere to each other & rough surfaces 4. When platelets come in contact w/collagen from connective tissue, they develop spiny projections; helps them adhere 5. Eventually platelet plug is formed & bleeding stops

5. Clotting Process - Coagulation Cascade effect - Extrinsic clotting – occurs when b.v. are damaged; platelets 1 st release serotonin

6. Blood Clots Thrombus – Embolus – blood clot or fragment of one that dislodges & travels to major organ

7. Plasma Clear, straw-colored fluid; matrix of blood 92% water Functions: 1. 2. maintain fluid balance 3.

8. Contents of Plasma Contains 3 plasma proteins (all produced in the liver): 1.Albumin – accounts for 60% of all plasma proteins - maintains osmotic pressure (keeps concentration of H 2 O & solutes in plasma stable - example – a decrease in albumin causes cells to lose H 2 O; it collects in interstitial spaces (b/t cells) & causes edema

9. Plasma Proteins 2.Globulins – 3.Fibrinogen – Accounts for 4% of all plasma proteins - responsible for blood clotting

10. Other Substances Plasma also contains: nonprotein nitrogenous substances – electrolytes – release ions when dissolved in H 2 O; maintain osmotic pressure & pH; include Na, K, Cl, Ca Mg, bicarbonate, PO 4 & SO 4 ions

11. Blood Types Antigen – protein on surface of RBC’s Determines blood type Possible antigens – A or B Antibody – Possible antibodies – A or B

12. Human Blood Types

13. Intrinsic Clotting (Agglutination) Occurs when antigen comes in contact with foreign antibody (example – b.t. A receiving a transfusion of b.t. B) Effects – Symptoms – anxiety, difficulty breathing, chest pain, pain in neck & lumbar area

14. Rh Blood Group 85% of humans have an additional protein on their RBCs; called the Rh factor Named after the species of monkey it was discovered in (Rhesus) Remaining 15% of humans don’t have this protein Rh- individuals cannot receive Rh+ blood

15. Erythroblastosis Fetalis