GMS 6530: Final Exam Flashcards Questions
With Complete Solutions
Structure of the Heart Wall - endocardium (thin), myocardium (muscle, larger; actually contracts), epicardium (same as pericardium/visceral), pericardial cavity (empty) --> parietal pericardium, fibrous layer
Interatrial septum - partition between the right and left atria
interventricular septum - separates right ventricle and left ventricle
What controls the movement of blood through the heart? - 1. opening and closing of the valves
2. contraction and relaxation of the myocardium
Flow of Blood through the heart - 1. superior vena cava/inferior vena cava/coronary sinus
2. right atrium
3. tricuspid valve
4. right ventricle
5. pulmonary valve
6. pulmonary trunk
7. left and right pulmonary arteries (deoxygenated)
8. lungs (loss of CO2, gain of O2)
9. right and left pulmonary vein (oxygenated)
10. left atrium
11. bicuspid/mitral valve
12. left ventricle 13. aortic valve
14. aorta
15. goes to rest of tissues in body
Where does cardiac excitation begin? - SA node in the right atrial wall
atrioventricular node (AV) location - interatrial septum, *action potential slows considerably* to contract the heart sequentially and provide time for atria to empty their blood into the ventricles.
ECG - recording of electrical changes that accompany the heartbeat. Conduction of action potentials through the heart generates electrical currents that can be picked up by electrodes placed on the skin
Three Recognizable Waves that Accompany Each Heartbeat - 1.
P wave (small upward deflection on ECG) --> atrial depolarization (contraction)
2. QRS complex (downward deflection, upward deflection, downward deflection) --> ventricular depolarization (contraction)
3. T wave (upward deflection) --> ventricular repolarization
What happens to atrial repolarization in the ECG? - buried in QRS complex
Positive chronotropic agent - increases HR Negative chronotropic agent - decreases HR
Does the ANS initiate the heartbeat? - No, the SA node does. The ANS controls the rhythm and force, not the SA node.
Where is the cardiac center? - medulla oblongata (initiates autonomic output to the heart)
Sympathetic Effect on Heart - postganglionic fibers are adrenergic (release norepinephrine)
binds to Beta adrenergic fibers in the heart
activates cAMP second-messenger system
leads to opening of Ca2+ channels in plasma membrane
greater Ca2+ --> harder contraction, faster contraction and relaxation, more often contractions
What happens at excessively high heart rates (>160)? - Diastole becomes too brief for adequate filling --> large decrease in stroke volume
Parasympathetic Effect on Heart - cholinergic, inhibitory effects on SA and AV nodes
acetylcholine binds to muscarinic receptors
opens K+ gates in nodal cells
As K+ leaves the cells, they become HYPERPOLARIZED (fire less frequently)
heart slows down
With Complete Solutions
Structure of the Heart Wall - endocardium (thin), myocardium (muscle, larger; actually contracts), epicardium (same as pericardium/visceral), pericardial cavity (empty) --> parietal pericardium, fibrous layer
Interatrial septum - partition between the right and left atria
interventricular septum - separates right ventricle and left ventricle
What controls the movement of blood through the heart? - 1. opening and closing of the valves
2. contraction and relaxation of the myocardium
Flow of Blood through the heart - 1. superior vena cava/inferior vena cava/coronary sinus
2. right atrium
3. tricuspid valve
4. right ventricle
5. pulmonary valve
6. pulmonary trunk
7. left and right pulmonary arteries (deoxygenated)
8. lungs (loss of CO2, gain of O2)
9. right and left pulmonary vein (oxygenated)
10. left atrium
11. bicuspid/mitral valve
12. left ventricle 13. aortic valve
14. aorta
15. goes to rest of tissues in body
Where does cardiac excitation begin? - SA node in the right atrial wall
atrioventricular node (AV) location - interatrial septum, *action potential slows considerably* to contract the heart sequentially and provide time for atria to empty their blood into the ventricles.
ECG - recording of electrical changes that accompany the heartbeat. Conduction of action potentials through the heart generates electrical currents that can be picked up by electrodes placed on the skin
Three Recognizable Waves that Accompany Each Heartbeat - 1.
P wave (small upward deflection on ECG) --> atrial depolarization (contraction)
2. QRS complex (downward deflection, upward deflection, downward deflection) --> ventricular depolarization (contraction)
3. T wave (upward deflection) --> ventricular repolarization
What happens to atrial repolarization in the ECG? - buried in QRS complex
Positive chronotropic agent - increases HR Negative chronotropic agent - decreases HR
Does the ANS initiate the heartbeat? - No, the SA node does. The ANS controls the rhythm and force, not the SA node.
Where is the cardiac center? - medulla oblongata (initiates autonomic output to the heart)
Sympathetic Effect on Heart - postganglionic fibers are adrenergic (release norepinephrine)
binds to Beta adrenergic fibers in the heart
activates cAMP second-messenger system
leads to opening of Ca2+ channels in plasma membrane
greater Ca2+ --> harder contraction, faster contraction and relaxation, more often contractions
What happens at excessively high heart rates (>160)? - Diastole becomes too brief for adequate filling --> large decrease in stroke volume
Parasympathetic Effect on Heart - cholinergic, inhibitory effects on SA and AV nodes
acetylcholine binds to muscarinic receptors
opens K+ gates in nodal cells
As K+ leaves the cells, they become HYPERPOLARIZED (fire less frequently)
heart slows down
