1. The Cardiac Cycle Refers to the events of 1 complete heart beat – Both atria & ventricles contract then relax (0.8 sec if beating 75x/min) Key terms to know – Diastole- relaxation – Systole- contraction – Lub-dub- the sound created by the closing of the heart valves (AV and semilunar)

3. Filling Heart Chambers: Cardiac Cycle Figure 11.7, step 1a Mid-to-late diastole (ventricular filling) Ventricular filling Left atrium Right atrium Left ventricle Right ventricle

4. Filling Heart Chambers: Cardiac Cycle Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular filling Left atrium Right atrium Left ventricle Right ventricle Mid-to-late diastole— blood flows from the atria into the ventricles (both chambers are relaxed, AV valves open) then the atria contract to squeeze remaining blood into the ventricles

5. Filling Heart Chambers: Cardiac Cycle Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular systole (atria in diastole) Isovolumetric contraction phase Ventricular filling Left atrium Right atrium Left ventricle Right ventricle

6. Filling Heart Chambers: Cardiac Cycle Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular systole (atria in diastole) Isovolumetric contraction phase Ventricular ejection phase Ventricular filling Left atrium Right atrium Left ventricle Right ventricle Ventricular systole— blood pressure builds before ventricles contract, when ventricles begin to contract pressure gets high enough opening the semilunar valves allowing blood to be pushed out to the lungs and body

7. Filling Heart Chambers: Cardiac Cycle Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular systole (atria in diastole) Early diastole Isovolumetric contraction phase Ventricular ejection phase Isovolumetric relaxation Ventricular filling Left atrium Right atrium Left ventricle Right ventricle Early diastole— atria finish refilling, when the pressure in the atria exceeds the pressure in the ventricles the AV valves will open allowing blood to fill the ventricles  the cycle begins again

8. Murmur- condition in which one of the valves is not functioning properly (could be an AV or semilunar valves) and blood can flow backwards/inefficiently through the heart.

9. Which phase of the cardiac cycle does this picture show? How can you be sure?

10. Factors that Affect CO 1. Venous return (amount of blood that enters the heart) – Inc. venous return  inc. stretching 2. How much the ventricle is stretched prior to contraction – Inc. stretching  inc. force of contraction 3. High blood pressure

11. Factors that Change Heart Rate Crisis stressors – Electrical system of the heart is more strongly stimulated to beat  inc heart rate Congestive heart failure – Heart “worn out” – digitalis (drug) prescribed, strengthens contractions to inc. cardiac output Epinephrine & thyroxine increase heart rate Electrolyte levels (ions) – Low calcium depresses heart; high calcium causes sustained contraction  can cause cardiac arrest – Low potassium  irregular heartbeat

12. Physical Factors that Affect Heart Rate Age – HR decreases with age (healthy) Gender – Females > males Exercise – increases HR Body temp – higher temp increases HR

13. The Cardiac Cycle Refers to the events of 1 complete heart beat – Both atria & ventricles contract then relax (0.8 sec if beating 75x/min) Key terms to know – Diastole- relaxation – Systole- contraction – Lub-dub- the sound created by the closing of the heart valves (AV and semilunar)

15. Filling Heart Chambers: Cardiac Cycle Figure 11.7, step 1a Mid-to-late diastole (ventricular filling) Ventricular filling Left atrium Right atrium Left ventricle Right ventricle

16. Filling Heart Chambers: Cardiac Cycle Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular filling Left atrium Right atrium Left ventricle Right ventricle Mid-to-late diastole— blood flows from the atria into the ventricles (both chambers are relaxed, AV valves open) then the atria contract to squeeze remaining blood into the ventricles

17. Why?

18. Filling Heart Chambers: Cardiac Cycle Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular systole (atria in diastole) Isovolumetric contraction phase Ventricular filling Left atrium Right atrium Left ventricle Right ventricle

19. Filling Heart Chambers: Cardiac Cycle Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular systole (atria in diastole) Isovolumetric contraction phase Ventricular ejection phase Ventricular filling Left atrium Right atrium Left ventricle Right ventricle Ventricular systole— blood pressure builds before ventricles contract, when ventricles begin to contract pressure gets high enough opening the semilunar valves allowing blood to be pushed out to the lungs and body

20. Filling Heart Chambers: Cardiac Cycle Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular systole (atria in diastole) Early diastole Isovolumetric contraction phase Ventricular ejection phase Isovolumetric relaxation Ventricular filling Left atrium Right atrium Left ventricle Right ventricle Early diastole— atria finish refilling, when the pressure in the atria exceeds the pressure in the ventricles the AV valves will open allowing blood to fill the ventricles  the cycle begins again https://www.youtube.com/watch?v=rguztY8aqpk

21. Think about it… What do you suspect happens to the coronary blood vessels as the heart goes through the cardiac cycle? – What would happen to them during systole? – What would happen to them during diastole?

22. Coronary Blood Vessels Feed the cardiac muscle with oxygen rich blood The coronary vessels branch off of the base of the aorta Only fill with blood when the pressure inside of the aorta is low and the blood flows back towards the heart https://www.youtube.com/watch?v=tBQa8IBzP6I&feature=related

23. What happens to a heart if it can’t get enough oxygen? HEART ATTACK

24. Why? https://www.youtube.com/watch?v=eTKICIpShaA&feature=related http://www.youtube.com/watch?v=DGxS44-rcps

26. Factors that Affect CO 1. Venous return (amount of blood that enters the heart) – Inc. venous return  inc. stretching 2. How much the ventricle is stretched prior to contraction – Inc. stretching  inc. force of contraction 3. High blood pressure

27. Factors that Change Heart Rate Crisis stressors – Electrical system of the heart is more strongly stimulated to beat  inc heart rate Congestive heart failure – Heart “worn out” – digitalis (drug) prescribed, strengthens contractions to inc. cardiac output Epinephrine increase heart rate Electrolyte levels (ions) – Low calcium depresses heart, high calcium can cause sustained contraction leading to cardiac arrest – Low potassium causes irregular heartbeat

28. Physical Factors that Affect Heart Rate Age – HR decreases with age (healthy) Gender – Females > males Exercise – increases HR Body temp – higher temp increases HR