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30 Cards in this Set
- Front
- Back
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Layers of the Heart
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Endocardium
Myocardium Epicardium |
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Endocardium
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Smooth epithelial cells
Lines the chambers of the heart Covers the valves |
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Myocardium
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Cardiac muscle
Thickest layer Pumps blood Lightly striated Involuntary Single nuclei in cardiac cells Branching cellular networks |
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Epicardium
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Serous Membrane
Visceral layer of the pericardium |
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Pericardium
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Sac that encloses the heart
Two aspects: Fibrous Pericardium Serous Pericardium |
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Fibrous Pericardium
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Outer layer
Heaviest layer Anchors the heart to the diaphragm, sternum |
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Serous Pericardium
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Parietal Pericardium-Outer layer
Parietal Cavity-Thin layer of fluid which reduces friction |
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One-way Valves
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Tricuspid Valve
Bicuspid Valve Pulmonary Valve Aortic Valve |
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Tricuspid Valve
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Between the right atrium and ventricle
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Bicuspid Valve
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Between the left atrium and ventricle
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Pulmonary Valve
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Between the right ventricle and pulmonary artery
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Aortic Valve
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Between the left ventricle and aorta
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Septum
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Divides the chambers of the heart
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Systemic Circulation
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Greater resistance to blood flow than pulmonary circulation
Flow must be consistent so force in left ventricle must be greater Slow and spontaneous depolarization |
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Atrioventricular Node
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Between the atria and the ventricles
Part of the heart conduction system Slower process than sinoatrial node AV Bundle: Branches to all portions of the ventricles |
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Purkinje Fibers
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myofibers that conduct impulse to the myocardium of the ventricles
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Conduction Pathway of the Heart
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1) SA node sends AP
2) Atria contracts with AV node triggered 3) AV node sends AP 4) Bundle of his triggers purkinje fibers to cause ventricles to contract 5) All the ventricles contract at once |
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ANS Heart Control: Sympathetic Nervous System
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Increases heart rate
Increases contraction force of myocardium Acts on SA/AV nodes Cardiac output can increase two to three times normal |
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ANS Heart Control: Parasympathetic Nervous System
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Decreases heart rate to restore homeostasis through the Vagus nerve
Acts on SA/AV Nodes |
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Systole
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Contraction of the heart
AV Valve Closes |
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Diastole
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Relaxation phase of the heart
AV Valves open |
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Heart Sound: Lub
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First sound
AV valve closes and blood vibration makes sound Longer, lower pitched sound start of ventricular systole |
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Heart Sound: Dub
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Second sound
Semilunar valves closing Shorter, Sharper sound Ventricular relaxation |
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Pulmonary Blood Flow
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1) Right Ventricle
2) Pulmonary Artery 3) Lungs 4) Pulmonary Veins 5) Left Atrium |
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Systemic Blood Flow
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1) Left Ventricle
2) Aorta 3) Tissues 4) System Veins 5) Superior/Inferior Vena Cava 6) Right Atrium |
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Total Blood volume
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5.5 Liters
70-80 ml per beat |
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Factors that Affect Blood Pressure
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Vessel diameter
Vessel Elasticity Blood Viscosity Blood Volume |
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End-diastolic Volume (EDV)
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Volume of blood in the ventricles at the end of diastole
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Total Peripheral Resistance
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Frictional resistance, or impedance, to blood flow in the arteries
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Contractility
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Strength of ventricular contractions
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