Bioengineering Systems Physiology Frog LabSlide 1 Leftovers Bioengineering/Physiology 6000

Bioengineering Systems Physiology Frog LabSlide 2 Altitude and Pulmonary Edema At sea level, reduced oxygen concentration comes from restricted air flow and capillaries constrict to increase flow in unrestricted airways At altitude, reduced oxygen concentration is widespread but the resulting capillary constriction is uneven Result is increase pressure in some alveolae and edema Edema is patchy but still very dangerous

Bioengineering Systems Physiology Frog LabSlide 3 Comments on Anatomy Lab Bioengineering/Physiology 6000

Bioengineering Systems Physiology Frog LabSlide 4 Comments Structure; –Intro/overview –Methods –Results and observations –Discussion Writing –Clear, concise, factual –Careful wording for accuracy –Facts over opinion Preparation –Figures and captions –Incorporate figures and tables in the text –All measurements in SI system

Bioengineering Systems Physiology Frog LabSlide 5 Frog Lab: Control of the Heart Bioengineering/Physiology 6000

Bioengineering Systems Physiology Frog LabSlide 6 Regulation of Heart Rate SA Node ACh ACh: increases p K reduces I f (muscarinic receptor) Epi, NE Epi/NE; increases I f (  1 -adrenergic receptor)

Bioengineering Systems Physiology Frog LabSlide 7 Regulation of Cardiac Contractility Increase in amplitude or rate of rise of isometric tension at fixed length, Free [Ca +2 ] i is key component Positive inotropic agents: –epinephrine: stimulate  receptors and increase Ca +2 influx and uptake (load SR) –Caffeine: increases sensitivity of myofilaments and causes release of SR Ca +2 Negative inotropic agents: –ACh: acts mostly on atria to shorten AP and reduce [Ca +2 ] i –Cadmium: resembles Ca +2 enough to block channel Muscle tension Passive (rest) tension Total tension Twitch tension Muscle length Effect of NE/E

Bioengineering Systems Physiology Frog LabSlide 8 Effect of E/NE on Contraction constant pretension reduced shortening (limited by max tension curve) reduced stroke volume tension [g] muscle length maximum isotonic tension Pressure Volume Left Ventricle stroke volume

Bioengineering Systems Physiology Frog LabSlide 9 Amphibians (e.g., Frog) Shared ventricle but blood separated –Spiral fold –Initial flow through pulmonary because of reduced pressure –Resistance to flow varies with breathing (inhale reduces resistance)

Bioengineering Systems Physiology Frog LabSlide 10 Lab Interventions Cold Ringer’s solution ACh Epinephrine Isoproterenol Ca 2+ -free solution Caffeine Cadmium chloride Potassium chloride

Bioengineering Systems Physiology Frog LabSlide 11 Midterm Bioengineering/Physiology 6000

Bioengineering Systems Physiology Frog LabSlide 12 Midterm Information See web site for study topics Format: –True/false –Short essay –Closed book Try and start on time