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Blood and Hemostasis
Phys Exam 3
Question | Answer |
---|---|
Hematocrit | the fraction of the blood volume that is occupied by red blood cells |
Major components of Blood | Plasma (Water, electrolytes, proteins) Erythrocytes, leukocytes, platelets |
Erythrocytes | *RBC's *carry O2 *Have Heme (iron) which binds O2 *Produced by erythropoiesis in long/flat bones *Kidneys stimulate RBC production by hormone erythropoietin |
Blood type | A, B, AB or O AB universal recipient, O universal Donor |
5 types of leukocytes | *Neutrophils *Eosinophils *Basophils *Monocytes *Lymphocytes |
Functions of Leukocytes | IMMUNE SYSTEM defend against viral, bacterial, parasitic, and fungal infections, I.D. and destroy cancer cells Phagocytosis of debris from dead or injured cells |
Hemostasis | Stopping bleeding |
Three steps of Hemostasis | Vascular spasm, formation of platelet plug, blood coagulation |
Neutrophils | *Majority of WBCs *Phagocytic and short lived *↑ in number during infections |
Eosinophils | *Small proportion of WBC's *Phagocytic and defend againts parasites |
Basophils | *Non-phagocytic and defend using toxins *Allergic reactions - produce histamine and heparin |
Monocytes | Large phagocytic macrophages that wander blood looking for invaders |
Lymphocytes | Large portion of WBC's Mainly involved in immune reactions (B Cells and T cells) |
Platelet adhesion | Blood vessel damage → Exposure of subendothelium → Von Wollibrandt's Factor binds to collagen fibers → Platelets bind to vWf → platelet adhesion |
Aggregation | Aggregated platelets release secretory products that increases the stickiness of the platelets and cause vasoconstriction to reduce blood flow to the area (reduces bleeding) |
Chemicals that prevent platelet aggregation | Prostacyclin Nitric Oxide Produced/released by healthy endothelial cells |