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17 Cards in this Set
- Front
- Back
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Do the artia contract as one unit?
Do the ventricles contract as one unit? |
yes
yes |
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Is there a slight delay between atrial and ventricular contractions?
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yes
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When the heart is at rest, what is it called?
What about during contraction? |
diastole
systole |
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What does the autonomic nervous system do to the heart?
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modulates
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What makes up the majority of the mass of the heart?
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cardiac muscle
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5 things the same in cardiac muscle and skeletal muscle?
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striations
tropomyosin troponin sarcoplasmic reticulum t-tubule system |
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2 different things between cardiac muscle and skeletal muscle?
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1) cardiac muscles do not have defined end plates like skeletal, they are connected by gap junctions (though intercalated discs)
2) Many different types of voltage-gated channels in its membrane (delayed opening, long lasting, etc) |
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What is end diastolic volume?
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The amount of blood in the ventricle right before systole (end of diastole)
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What is stroke volume?
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The amount of blood ejected from the ventricle during one heartbeat (one contraction)
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What is Starling's Law of the Heart?
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Within limits (in the body under normal controls) the heart will pump all the blood it receives
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Another name for autorythmic cells?
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pacemaker cells
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What is a pacemaker cell?
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a cell in the heart that "spontaneously" depolarizes to threshold
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What percentage of filling happens without atrial contraction?
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80%
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How do you measure cardiac output?
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CO=HRxSV
Heart rate x stroke volume |
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The parasympathetic system innervates the heart thru what nerve?
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Vagus nerve
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What does EPI and NE do?
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They cause faster depolarization by making permeability to Ca++ and Na+ higher (they bind to the same receptors, there is no difference)
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What does Ach do?
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Slows heart down by delaying the closing of K+ channels
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