BIO 311D 2nd Edition Lecture 28 Outline of Last Lecture I Partial Pressure Differences Affect Diffusion II Hemoglobin in red blood cells binds O2 III Clicker quiz questions about hemoglobin IV Circulatory system Outline of Current Lecture I How are circulatory systems organized II Evolution of the heart in vertebrates III Introduction to blood and lymph IV In class exercise index card questions Current Lecture I II Circulatory Systems A 3 major types of blood vessels artery capillary and vein a Artery smooth muscles b Exchange of gases and solutes between blood and other tissues occurs capillaries only B In the vertebrates respiratory systems are closely related to the circulatory system including heart structure are closely related Evolution of the heart in vertebrates A The closed circulatory system of vertebrates has evolved from a two chambered heart in fish B Frogs have an extra pulmonary circulation loop and a 3 chamebered heart What is the adaptive advantage of having blood return to the heart before going out to the systemic circulation Extra push on the heart C Birds and mammals have 4 chambered heart with two pathways by which blood leaves and returns to the heart Oxygenated and deoxygenated blood totally separated 1 Blood in the pulmonary circuit passes through the lungs and becomes oxygenated then returns to the left side of the heart 2 Oxygenated blood in the systemic circuit is pumped to all other tissues of the body providing them with O2 This blood becomes deoxygenated and returns to the right side of the heart D Pathway of blood through the heart III 1 2 3 4 Introduction to blood and lymph A Describe how blood pressure and blood velocity change as blood travels through the circulatory system and explain these changes What is the advantage of slow blood flow through the capillaries a Pressure drops as blood travels from the arteries to the capillaries Pressure never picks up again b Speed velocity drops but does pick up again Slowing down blood flow allows greater gas exchange through diffusion B Water a Reduces blood volume pushes water out fluid pressure b Draws water back at the venous end solute concentration C Control of local blood flow through the capillaries by adjusting sphincter muscles a Sphincter relax b Sphincter contracts D A drop of blood is in an artery in your left arm flowing out towards your fingers A minimum of how many capillary beds will it pass through before it gets to the same location in your arm again 2 In the artery therefore is already oxygenated Capillary beds in arm or fingers initial meeting Vein heart right atrium lungs capillaries E What is the sequence of heart contraction Pacemaker generates wave of signals to contract Signals are delayed at AV node Signals pass to heart apex Signals spread throughout ventricles a Pacemaker cells in the SA node are autorhythmic fire spontaneously initiates heartbeat b Cardiac muscles cells are connected by gap junctions and desmosomes F If removed from the body the heart will keep beating G Heart rate can be affected by input from outside the heart when you exercise when you re nervous etc H Composition of blood 55 plasma 45 cellular a Blood plasma composition is usually at equilibrium with the interstitial fluidIndex Questions
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