BIO 251 1st Edition Lecture 17 Outline of Last Lecture I. Arteries II. Arterials III. Control of arteriolar radius a. Intrinsic factors b. Extrinsic factors IV. Capillaries a. Intro b. Molecular structure c. Gross structure d. Function e. Control of flow V. Lymph system a. Problem b. Solutionc. Most important functions VI. Veins a. Function b. Venous return These 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.Outline of Current Lecture I. Components of blood II. Plasma a. Compositions III. Erythrocytes a. Structure & function IV. Hematocrit V. Leukocytes a. Basics VI. Platelets a. Structure b. Function VII. Hemostasis a. 3 stepsi. Vascular spasms ii. Platelet aggregation iii. Coagulation VIII. Flow rate of blood IX. Blood pressure Current Lecture-Components of bloodoPlasma -Liquid portion of blood oErythrocytes-RBCoLeukocytes-WBCoPlatelets -Involved in blood clotting-PlasmaoCompositions (table 15.1)-90% water-8% plasma proteins -1% inorganic ions -Na+ & Cl--1% nutrients, waste, hormones, ect-Erythrocytes (RBC)oStructure & function (15.1)-Flat, thin, disk shaped cells-Gives large surface area for diffusion of O2-Thinness allows rapid diffusion of O2-Membrane is flexible -Allows cell to take odd shapes/ squeeze through narrow openings -Each contain several hundred million hemoglobin (Hb) moles. So full of Hb that it -Has no nucleus -Has no organelles -Essentially a sec of Hb-Contain -Glycolytic enzymes for energy production -Carbonic anhydrase which converts to CO2 to bicarbonate for transport back to lungs-Production & destruction -Lasts about 4 months (short life)-Replaced at avg rate of 2-3 million/sec -Most old erythrocytes removed by spleen-New are produced by bone marrow oHematocrit (15.2)-99% cells in blood are erythrocytes -Packed cell volume after centrifugation is composed almost entirely of erythrocytes; packed cell volume called hematocrit -Hematocrit levels avg 42% for females, 45% for men -Cream colored layer on top of erythrocytes called Buffy layer-Composed of WBC and platelets-Leukocytes (WBC)oBasics-Mobile units of immune system -Defend against pathogens-Identify & destroy cancer cells -Destroy cellular debris in body -Use a seek & destroy approach-Do most of their work in tissues, only use blood as transport-Platelets oStructure -Small cell fragments from bone marrow-bound cells -Contain actin & myosin -Do not leave blood but can be stored in spleen -Functional for about 10 days oFunction -Involved in blood clotting during injury -Hemostasis (arrest of bleeding from a broken blood vessel)oOccurs in 3 major steps -Vascular spasms -Reduce blood flow -Causes broken pieces of vessel to stick together-Platelet aggregation (15.7)- Under normal conditions-Vessel releases prostacyclin which inhibits platelet aggregation -When damage occurs in vessel-Prostacyclin production stops & platelets attach to collagen exposed by damage-Attached platelets release 2 chemicals that causes nearby platelets to get sticky and aggregate together -Platelet actin & myosin contract & strengthen aggregate -Additional vasoconstrictors released to reduce local blood flow -Release additional chemicals needed for coagulation -Coagulation (15-10)-Damage & platelet aggregation initiate cascade of clotting factors -Eventually fibrinogen (blood protein) converted to fibrin by thrombin-Fibrin is loose protein meshwork-Thrombin also activates factor XIIIa-Factor XIIIa stabilizes fibrin into stabilized meshwork -Becomes a clot as blood cells get caughtin it -Flow rate of blood oF=deltaP/R-F= flow rate = cardiac output -deltaP = pressure gradient = BP-Difference in pressure between beginning & end of a blood vessel -Main driving force for blood flow through cardiovascular system -R = resistance -Measure of hindrance to blood flow caused by friction between blood & walls of blood vessel-Smaller the vessel, greater the resistance-Small vessel, larger volume of fluid comes into contact with more surface area of vessel -Small change in radius has huge impact on resistance -Res infinity 1/radius ^4-Doubling the radius decreases the resistance 16 times & therefore increases the flow rate 16-fold-Blood pressure oRewrite flow rate as deltaP= FR: BP = CO x Resistance oShort term regulation of BP-Baroreceptor reflex -Location of 2 most important (14.26)-Aortic arch -Carotid sinus-Usual reflex arch -Receptor -Afferents pathway -Integrating center (cardiovascular control in Medulla)-Efferent pathway (ANS)-Receptor organs -Baroreceptor constantly action potentials (14.27)-When BP increases, AP frequency increases -When BP decreases, AP frequency decreases -Cardiovascular response to exercise (box 428)-Chemoreceptors in carotid arch & aortic arteries are sensitive to O2, CO2 and acid levels-Reflexively increase respiration and BP during exercise -Emotions & behaviors (fight or flight, orgasms, blushing)-Hypothalamic control over skin arterials for temp regulation overrides cardiovascular center over these arterials oLong term regulation of blood pressure -Control of plasma volume -By left atrial volume receptors & hypothalamic osmoreceptors -Control of urine output & thirst oMeasuring arterial BP (14.8)-Large number is systolic pressure -Small number is diastolic pressure -Mean arterial pressure = (systolic pressure + [2 x diastolic pressure])/3-Diastole is twice as long as systole when person at rest-Example -(110+[2 x 70])/3 = 83.3 mmHg-Mean arterial pressure is regulated by BP reflexes -Mean arterial pressure during exercise:-Systolic + diastolic /