📘 Chapter 19: Blood – Full Simplified Study Notes (27 Slides) ⸻ Slide 1: Cardiovascular System • Cardiovascular system = heart, blood, blood vessels. • Blood’s job: • Delivers nutrients, hormones, oxygen, and chemical messages. • Carries immune cells to fight infections. • Why it matters: Without this transport system, cells would starve and toxins would build up. • Analogy: Like UPS + garbage service → delivers packages (nutrients, O₂) and removes trash (waste, CO₂). ⸻ Slide 2: Whole Blood • Whole blood = plasma + formed elements. • Hematocrit: percentage of blood volume made of cells. • Plasma: watery fluid. • Key properties of blood: • Temp: 38°C (100.4°F) → warmer than body surface. • Thickness: 5x thicker than water. • pH: ~7.4 (slightly alkaline). • Volume: Men = 5–6 L, Women = 4–5 L. • About 7% of body weight. • Example: If someone weighs 150 lbs, about 10 lbs of that is blood. ⸻ Slide 3: Blood Plasma • Plasma = liquid with proteins + solutes. • Proteins: • Albumins: keep water inside blood vessels (prevent swelling). • Globulins: antibodies → defense. • Fibrinogen: forms clots. • Other solutes: • Electrolytes: Na⁺, K⁺, Cl⁻, HCO₃⁻ (important for nerves/muscles). • Nutrients: glucose, fructose, amino acids. • Wastes: urea, uric acid. • Analogy: Plasma = soup broth carrying salt, sugar, proteins, and waste. ⸻ Slide 4: Formed Elements • Red Blood Cells (RBCs / erythrocytes): 99.9% of all blood cells. • RBC count: Men = 4.5–6.3 million/μL, Women = 4.2–5.5 million/μL. • Platelets: fragments needed for clotting. • White Blood Cells (WBCs / leukocytes): fight disease. • Think: Plasma is the liquid, formed elements are the “stuff floating inside.” ⸻ Slide 5: RBC Structure • RBCs lose their nucleus & organelles. • Consequences: • Can’t divide. • Can’t make proteins or repair. • Only use glycolysis (anaerobic metabolism) → no oxygen needed for energy. • Analogy: Like delivery trucks with no engine shop → they drive until they break down. ⸻ Slide 6: RBC Lifespan • RBCs have no nucleus, mitochondria, ribosomes → no repair. • Rely on glycolysis for energy. • Live about 120 days. • Must be recycled by spleen/liver. • Example: Like a disposable battery that runs until it dies. ⸻ Slide 7: RBC Shape & Function • Shape = biconcave disc (doughnut-like, thin middle). • Benefits: • High surface area → better oxygen exchange. • Can stack like coins → smooth flow. • Flexible → squeeze through tiny capillaries. • Analogy: Like a flexible frisbee that can bend and stack. ⸻ Slide 8: Hemoglobin • Main protein inside RBC. • Structure: • 2 alpha chains + 2 beta chains. • Each has heme group with iron atom (Fe). • Function: Iron binds oxygen → carries it around body. • Why recycle? Iron is valuable, so old RBCs get broken down to save it. • Analogy: Hemoglobin = oxygen backpack. ⸻ Slide 9: RBC Lifecycle • Starts from hemocytoblast (stem cell). • Branches into: • Myeloid stem cells: make RBCs + some WBCs. • Lymphoid stem cells: make lymphocytes. • Think: Hemocytoblast = tree trunk, RBCs and WBCs = branches. ⸻ Slide 10: RBC Production (Erythropoiesis) • Erythropoiesis = making RBCs. • Embryo: 1st 8 weeks = yolk sac → later liver, spleen, thymus, bone marrow. • Adult: red bone marrow only (vertebrae, sternum, ribs, skull, pelvis, ends of long bones). • Nutrients needed: amino acids, iron, vitamins B12, B6, folic acid. • Analogy: RBCs = cookies, bone marrow = kitchen, iron + vitamins = ingredients. ⸻ Slide 11: RBC Production Control • Controlled by erythropoietin (EPO). • Made by kidneys/liver when low oxygen (hypoxia). • Effects: • Increases stem cell division. • Speeds up hemoglobin production. • Blood doping: Athletes take EPO or reinfuse RBCs → more oxygen for muscles. • Risk: thicker blood → clots, strokes. • Analogy: EPO = coach yelling “make more RBCs!” ⸻ Slide 12: Blood Types • RBCs have antigens on membranes (A, B, AB, O). • Rh factor = + or –. • Plasma has antibodies (agglutinins): attack foreign antigens → cause clumping (agglutination). • Universal donor = O–. • Analogy: Blood type = ID card. If ID doesn’t match, antibodies attack. ⸻ Slide 13: RBC Summary • Know: • How typing works. • How RBCs are made. • What controls them. • Why they live 120 days. • How they’re broken down. • Analogy: RBCs = delivery trucks with expiration dates. ⸻ Slide 14: WBC Basics • WBCs = leukocytes. • Have nuclei, organelles, no Hb. • Functions: fight pathogens, remove wastes, destroy abnormal cells. • Only in blood briefly → then move into tissues. • Analogy: WBCs = body’s police force. ⸻ Slide 15: Neutrophils • 50–70% of WBCs. • Nucleus 2–5 lobes. • First responders → attack bacteria. • Use phagocytosis + enzymes. • Die quickly → pus = dead neutrophils + bacteria. • Analogy: Neutrophils = foot soldiers. ⸻ Slide 16: Basophils • <1% WBCs. • Release histamine (dilates vessels, causes swelling/redness). • Release heparin (prevents clots). • Trigger inflammation → work with mast cells. • Analogy: Basophils = fire alarms. ⸻ Slide 17: Eosinophils • 2–4% WBCs. • Stain red-orange. • Bi-lobed nucleus. • Kill parasites, respond to allergies. • Release toxic chemicals (nitric oxide, enzymes). • Help control inflammation. • Analogy: Eosinophils = exterminators. ⸻ Slide 18: Monocytes • 2–8% WBCs. • Largest WBC, kidney-shaped nucleus. • Become macrophages in tissue. • Eat large pathogens, dead cells. • Call fibrocytes → scar tissue. • Analogy: Monocytes = garbage trucks. ⸻ Slide 19: Lymphocytes • 20–30% WBCs. • Big nucleus, little cytoplasm. • Most live in lymph tissue. • Types: • T cells: attack infected cells. • B cells: make antibodies. • NK cells: kill cancer/virus cells. • Analogy: Lymphocytes = special forces. ⸻ Slide 20: WBC Production • From hemocytoblasts. • Myeloid stem cells: all except lymphocytes. • Lymphoid stem cells: lymphocytes. • Colony-Stimulating Factors (CSFs): • M-CSF = monocytes. • G-CSF = granulocytes. • GM-CSF = granulocytes + monocytes. • Multi-CSF = RBCs + WBCs + platelets. • Analogy: CSFs = managers assigning jobs. ⸻ Slide 21: Platelets • Fragments of cells, no nucleus. • Lifespan = 9–12 days. • Removed by spleen. • 2/3 stored for emergencies. • Analogy: Platelets = emergency patch kits. ⸻ Slide 22: Platelet Functions 1. Release clotting chemicals. 2. Form platelet plug at damage site. 3. Contract (actin + myosin) → shrink clot, close wound. • Analogy: Platelets = patch team pulling duct tape tight. ⸻ Slide 23: Hemostasis • Definition: stopping bleeding. • 3 phases: vascular, platelet, coagulation. • Analogy: Like fixing a leaking pipe step by step. ⸻ Slide 24: Vascular Phase • Vessel wall contracts (vascular spasm). • Endothelial cells: • Expose basement membrane. • Release endothelins → stimulate contraction/healing. • Become sticky → platelets attach. • Analogy: Pinch a hose to slow the leak. ⸻ Slide 25: Platelet Phase • Platelets stick to exposed collagen. • Form platelet plug (15 sec after injury). • Release chemicals: ADP, thromboxane A₂, serotonin, Ca²⁺, PDGF. • Feedback prevents over-clotting. • Analogy: Like putting your hand over a hole until repair arrives. ⸻ Slide 26: Coagulation Phase • Chain reaction of clotting factors. • Fibrinogen → fibrin (forms net). • Common pathway: 1. Factor X → prothrombinase. 2. Prothrombin → thrombin. 3. Fibrinogen → fibrin. • Clot retraction pulls vessel edges together. • Analogy: Casting a fishing net over the leak. ⸻ Slide 27: Fibrinolysis & Clotting Needs • Fibrinolysis: clot dissolves after healing. • t-PA → activates plasminogen → plasmin → digests fibrin. • Requirements for clotting: • Calcium (Ca²⁺): needed in all clotting steps. • Vitamin K: liver makes clotting factors; comes from food + gut bacteria. • Deficiency = bleeding problems. • Analogy: Once pipe is repaired, cut away the net (clot)