EXSS 276 1st Edition Lecture 24 Outline of Last Lecture I. Muscle CrampsII. Rigor MortisIII. Cardiac MuscleIV. Smooth Muscle (visceral) Outline of Current LectureI. Fluids of the BodyII. What is blood?III. Physical characteristicsIV. ComponentsV. ErythrocytesCurrent LectureCardiovascular System: BloodI. Fluids of the Bodya. Cells of the body are serviced by two fluidsi. Blood: composed of plasma and variety of cellsii. Transports nutrients and wastesb. Interstitial fluidi. Bathes cells of the bodyc. Nutrients and O2 diffuse from blood to the interstitial fluid and then into cells; wastes move in the reverse direction II. What is blood?a. Classified as a tissue of the bodyb. Fully moveable tissue since it circulates throughout the vascular bedc. Roles:i. Gas transportii. Nutrient transportiii. Waste removaliv. Temperature regulationv. Infection: immunological defensevi. Protection from disease and fluid lossIII. Physical characteristicsa. Thicker, more viscous than water; flows more slowlyb. 8% of total body weightThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.c. Volumei. 5-6L in malesii. 4-5 L in femalesiii. Hormonal negative feedback systems maintain constant blood volume and pressureIV. Componentsa. 55% plasmai. Over 90% waterii. 7% plasma proteins1. Created in liver2. Confined to bloodstream3. Albumin: 54-60% of plasma proteinsa. Maintain blood osmotic pressure4. Globulins (immunoglobulins)a. Antibodies bind to foreign substances called antigensb. Form antigen-antibody complexes5. Fibrinogena. Involved in clottingiii. 2% other substances 1. Electrolytes: help maintain osmotic pressure; essential role in cell function2. Nutrients: digestive products => all body cells3. Gases: O2, CO2, N24. Regulatory substances: enzymes, hormones, vitamins5. Waste products: breakdown products from protein metabolism to organs of excretion b. 45% formed elementsi. Thrombocytes/platelets/clotting component ii. Leukocytes/white blood cellsiii. Erythrocytes/red blood cellsV. Erythrocytesa. Normal RBC count: 5.4 million/drop (male); 4.8 million/drop (female)b. New RBCs enter circulation at 2 million/secondc. Unique properties for carrying gasesi. Contain oxygen-carrying protein hemoglobin, gives blood red colorii. 1/3 of cell’s weight is hemoglobind. Biconcave diski. Increased surface area/volume ratioii. Flexible shape for narrow passagesiii. No nucleus or other organelles1. No cell division or mitochondrial ATP formation2. What kind of metabolism? => anaerobic (allows them to transport more oxygen)e. Hemoglobini. Each hemoglobin molecule can carry 4 oxygen molecules from lungs to tissue cellsii. Hb transports 23% of total CO2 waste from tissues to lungs for release iii. Iron in the middle of hemef. Made in process called erythropoiesis (hemopoiesis) i. Stimulus: hypoxia due to decreased RBC count, decreased availability of O2 to blood, or increased tissue demands for O2ii. Reduced O2 levels in bloodiii. Kidney releases erythropoietin iv. Erythropoietin stimulates red bone marrowv. Enhanced erythropoiesisvi. More RBCsvii. Increased O2 carrying ability of bloodviii. Normal blood oxygen levelsix. Steps:1. Stem cell (hemocytoblast)2. Committed cell (proerythroblast)3. Phase 1: ribosome synthesis4. Phase 2: hemobloin accumulation5. Phase 3: ejection of nucleus6. Erythrocytesg. Life cyclei. RBCs live 120 days1. Wear out from bending to fit through capillaries2. No repair possible due to lack of organellesii. Worn out cells removed by macrophages in spleen and liveriii. Breakdown products are recycledh. Degradation and recycling of productsi. Globin => amino acids => reused for protein synthesis ii. Heme break down1. Iron changes to different form and joins with transferrin (moves iron to liver) => red bone marrow 2. Into bilirubin => to liver => excreted in urine i. Blood dopingi. Injecting previously stored RBCs before athletic event1. More cells available to deliver O2 to tissuesii. Dangerous1. Increases blood viscosity2. Forces heart to work harderiii. Banned by Olympic committee j. Related conceptsi. Hematocrit: percentage of blood volume composed by RBCsii. Difference females (38-46%) and males (40-54%)iii. Induced polycythemia: blood doping, altitude exposure k. Anemiai. Decreased erythropoiesis (building RBC)ii. Increased destruction of RBCsiii. Increased destruction of hemoglobiniv. Can result in1. Decreased capacity to carry gases2. Decreased acid buffering