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Chapter 14, part A

Chapter 14, part A

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Chapter 14, part A

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  1. Chapter 14, part A Cardiovascular Physiology

  2. About this Chapter • Blood flow pumping & distribution • Anatomy and histology of the heart • Mechanism of cardiac contraction • Heart beat sequence–how the pump works • Regulators of hear beat and volume pumped

  3. Overview of the Cardiosvascular System • Heart and Blood vessels • Products transported to sustain all cells Table 14-1: Transport in the Cardiovascular System

  4. Circulation Reviewed • Heart – "four chambered" • Right atrium & ventricle • Pulmonary circuit • Left atrium & ventricle • Systemic circuit • Blood Vessels – "closed circulation" • Arteries –from heart • Capillaries– cell exchange • Veins – to heart

  5. Circulation Reviewed Figure 14-1: Overview of circulatory system anatomy PLAY Animation: Cardiovascular System: Anatomy Review: The Heart

  6. Blood Flow: Pressure Changes • Flows down a pressure gradient • Highest at the heart (driving P), decreases over distance • Hydrostatic (really hydraulic) pressure in vessels • Decreases 90% from aorta to vena cava

  7. Blood Flow: Pressure Changes Figure 14-2 : Pressure gradient in the blood vessels

  8. Some Physic of Fluid Movement: Blood Flow • Flow rate: (L/min) • Flow velocity= rate/C-S area of vessel • Resistance slows flow • Vessel diameter • Blood viscosity • Tube length Figure 14-4 c: Pressure differences of static and flowing fluid

  9. Some Physic of Fluid Movement: Blood Flow Figure 14-6: Flow rate versus velocity of flow

  10. Heart Structure • Pericardium • Chambers • Coronary vessels • Valves-(one-way-flow) • Myocardium Figure 14-7 g: ANATOMY SUMMARY: The Heart

  11. Cardiac Muscle Cells: • Autorhythmic • Myocardial • Intercalated discs • Desmosomes • Gap Junctions • Fast signals • Cell to cell • Many mitochondria • Large T tubes Figure 14-10: Cardiac muscle

  12. Mechanism of Cardiac Muscle Excitation, Contraction & Relaxation Figure 14-11: Excitation-contraction coupling and relaxation in cardiac muscle

  13. Modulation of Contraction • Graded Contraction: proportional to crossbridges formed • More [Ca++]: crossbridges, more force & speed • Autonomic n & epinephrine modulation

  14. Modulation of Contraction Figure 14-12: Modulation of cardiac contraction by catecholamines

  15. More Characteristics of Cardiac Muscle Contraction • Stretch-length relationship •  stretch,  Ca++ entering •  contraction force • Long action potential • Long refractory period • No summation • No tetanus

  16. More Characteristics of Cardiac Muscle Contraction Figure 14-13: Length-tension relationships in skeletal and cardiac muscle

  17. More Characteristics of Cardiac Muscle Contraction Figure 14-15c: Refractory periods and summation in skeletal and cardiac muscle