1. Announcements 6 VFs passed! We will have “lectures” after exam Friday 17 th last day for wet experiments –can appeal for one more experiment Thursday 30th last day of VFs –show me TA practice receipts...

3. 3

4. Gas Exchange

5. CO 2 from tissue CO 2 + H 2 O HCO 3 – + H + Cl – HCO 3 – Red blood cell Plasma Transported in plasma Carbonic anhydrase Binds to hemoglobin At the tissue (the capillary bed by active muscle)

8. Four valves: prevent backflow, flaps of connective tissue AV Atrioventricular valves between each atrium and ventricle SL Semilunar valves between ventricles and departing arteries (when they slam closed they create heart sounds) The Heart: Structure -Structure four chambers and two-layered sac (pericardium). Two atria: collection chambers Two ventricles: thick walled pumps

9. Sinoatrial node Atrioventricular node Conducting fibers Left ventricle Left atrium Right atrium Right ventricle

10. -Regulation of SA and AV nodes: Nervous: Sympathetic : Parasympathetic (vagus) Hormones: Epi, ACh, Temperature, Exercise, pH these also effect blood vessels (constrict or relax PR) The Heart: Control -Cardiac cells: myogenic (self-excitable) in syncytium Controlled by sinoatrial (SA) node, the pacemaker. 1st: Atrial electrical wave -> two atria contract 2nd: wave at atrioventricular (AV) node, delayed 0.1s 3rd: Common bundle & Purkinje fibers to Ventricles

11. Sinoatrial node Atrioventricular node Conducting fibers Left ventricle Left atrium Right atrium Right ventricle

12. 00.1 Electrical activity in atria SA node activates atria AV node delay Electrical activity in ventricles Ventricles recover 0.2 Time (seconds) 0.30.40.5

13. Be the HEART and Depolarize

14. The Heart: Function -Function pump blood; create pressure gradient. Contraction and relaxation =cardiac cycle During systole, muscle contracts and pumps During diastole, muscle relaxes and chambers fill Sounds “Lub” AV, “Dub” SL, “ssssshh” murmur.

21. Properties of the Heart that Clinicians Examine Size/Volume Structure Pressure Generation Electrical Activity Efficiency

22. Properties of the Heart that Clinicians Examine Size/Volume Structure Pressure Generation Electrical Activity Efficiency

23. Size/Volume Right Atrium Right Ventricle Left Atrium Left Ventricle

24. When Things Aren’t Quite Right

25. After some time with this Atrial Septal Defect - how would the Chest X-ray change?

26. Hypertension is similar Left Ventricle

27. 27 Blood returning to the mammalian heart in a pulmonary vein drains first into the a) vena cava. b) left atrium. c) right atrium. d) left ventricle. e) right ventricle.

28. 28 Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a a) higher PO2. b) higher PCO2. c) greater bicarbonate concentration. d) lower pH. e) lower osmotic pressure.

29. 29 When you hold your breath, which of the following blood gas changes first leads to the urge to breathe? a) rising O2 b) falling O2 c) rising CO2 d) falling CO2 e) rising CO2 and falling O2