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Chapter 14, part A. Cardiovascular Physiology. 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. Overview of the Cardiosvascular System.
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Chapter 14, part A Cardiovascular Physiology
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
Overview of the Cardiosvascular System • Heart and Blood vessels • Products transported to sustain all cells Table 14-1: Transport in the Cardiovascular System
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
Circulation Reviewed Figure 14-1: Overview of circulatory system anatomy PLAY Animation: Cardiovascular System: Anatomy Review: The Heart
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
Blood Flow: Pressure Changes Figure 14-2 : Pressure gradient in the blood vessels
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
Some Physic of Fluid Movement: Blood Flow Figure 14-6: Flow rate versus velocity of flow
Heart Structure • Pericardium • Chambers • Coronary vessels • Valves-(one-way-flow) • Myocardium Figure 14-7 g: ANATOMY SUMMARY: The Heart
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
Mechanism of Cardiac Muscle Excitation, Contraction & Relaxation Figure 14-11: Excitation-contraction coupling and relaxation in cardiac muscle
Modulation of Contraction • Graded Contraction: proportional to crossbridges formed • More [Ca++]: crossbridges, more force & speed • Autonomic n & epinephrine modulation
Modulation of Contraction Figure 14-12: Modulation of cardiac contraction by catecholamines
More Characteristics of Cardiac Muscle Contraction • Stretch-length relationship • stretch, Ca++ entering • contraction force • Long action potential • Long refractory period • No summation • No tetanus
More Characteristics of Cardiac Muscle Contraction Figure 14-13: Length-tension relationships in skeletal and cardiac muscle
More Characteristics of Cardiac Muscle Contraction Figure 14-15c: Refractory periods and summation in skeletal and cardiac muscle