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29 Cards in this Set
- Front
- Back
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nervous control of heart
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-sympathetic nerve
-parasympathetic nerve |
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humoral control of heart
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1. hormones: epi, norepi
2. electrolytes: Na, K, Ca 3. drugs |
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parasympathetic nerve locations
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1. L and R atrium
2. SA node 3. AV node **not venticles** |
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sympathetic nerve locations
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1. L and R atrium
2. SA node 3. AV node 4. L and R ventricle |
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parasympathetic nerve effects
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decreases:
1. HR 2. speed of conduction: atrium 3. excitability: atrium ** not force of ventricular contraction ** |
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sympathetic nerve effects
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increases:
1. HR 2. speed of conduction 3. force of contraction 4. excitability |
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chronotropic
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HR
1. sympathetic + 2. parasympathetic - |
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dromotropic
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speed of conduction
1. sympathetic + 2. parasympathetic - to atria only |
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inotropic
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force of contraction
1. sympathetic + 2. parasympathetic - to atria only |
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bathmotropic
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excitability
1. sympathetic + 2. parasympathetic - to atria only |
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norepi
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-causes steeper diastolic depolarization through:
1. increased Na influx 2. decreased K efflux ... HR increases |
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acetylcholine
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-causes flatter diastolic depolarization:
1. increased K efflux 2. decreased Ca influx ... HR decreases |
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ANS and sleep
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PS dominates and subdues the S
- HR decreases - S dominates during day |
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ANS and increasing/extreme activity
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1. increasing: S gains strength and dominates PS
2. extreme: PS has no effect on heart |
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ANS and intrinsic HR
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when both PS and S nerves assert equal influence they eliminate each other and heart beats at intrinsic
rate of SA node |
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effects of norepi and epi
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-synthesized by adrenal gland and released into blood
-exert same effect on heart - Norepi also NT of sympathetic nerve: synthesized and released from varicosities of the sympathetic nerve |
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norepi/ epi and chronotropy
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+ chronotropy:
increased HR |
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norepi/epi and dromotropy
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+ dromotropy:
increased speed of conduction |
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norepi/epi and inotropy
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+ inotropy:
increased force of contraction |
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norepi/epi and bathmotropy
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+ bathmotropy:
increased excitability |
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Acetylcholine
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1. NT of PS nerve synthesized in synapses
2. exerts - tropic effects on the heart 3: NT: all skeletal mm, preganglionic of S and PS, postganglionic of PS |
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acetylcholine and chronotropy
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- chronotropy:
decreased HR |
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acetylcholine and dromotropy
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-negative dromotropy: only atria
-decreased speed of conduction |
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acetylcholine and inotropy
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-negative inotropy: only atria
- decreased force of contraction |
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acetylcholine and bathmotropy
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-negative bathmotropy: only atria
- decreased excitability |
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increased contractility
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-results in larger stroke V for any given end-diastolic V
1. norepi 2. isoprotenerol 3. cardia glycosides: digitalis |
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decreased contractility
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-smaller stroke V
1. drugs 2. heart failure |
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drugs that cause decreased contractility
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1. propanalol: Beta agonist
2. barbituates 3. anaesthesia 4. analgesia |
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heart problems that cause decreased contractility
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heart failure:
1. coronary artery disease 2. cardiac hypoxia 3. myocarditis 4. valvular defects 5. toxic reactions 6. electrolyte imbalances |
