Term
| cardiac cycle; takes about how long? |
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Definition
all events associated with one heart beat
.8 seconds at rest |
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Term
| heart rate is modified by |
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Definition
| changes in the Autonomic Nervous System |
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Term
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Definition
| effects of Autonomic nervous system on heart rate |
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Term
| ANS activity can be modified by |
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Definition
circulating hormones
higher brain structure |
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Term
| sympathetic neurons that send nerve fibers to the heart are located |
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Definition
| in teh caudal portions of medulla oblongata |
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Term
| "cardiovascular system" of brain |
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Definition
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Term
| neurons in CV center act upon |
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Definition
| preganglionic neurons in the intermediolateral cell columns of thoracic spinal cord |
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Term
| preganglionic neurons act upon ______ _____________ _________ |
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Definition
| postganglionic neurons which are located in the ganglia of sympathetic chain |
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Term
| postganglionic neurons send their axons to |
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Definition
| SA node AV node and cardiac muscle fibers |
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Term
preganglionic neurons release? onto?
postganglionic nuerons release? onto? |
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Definition
acetylcholine: postganglionic
norepinephrine: target cells |
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Term
| norepinephrine activates? which have: |
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Definition
| beta 1 receptors; wide spread effects on cardiac and muscle tissue |
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Term
| parasympathetic neurons in CV center of brain send their ___ to heart via ? |
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Definition
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Term
| Neurons from parasympathetic nerve fibers act directly upon |
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Definition
| sa node, av node and atrial fibers |
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Term
| neurons from parasympathetic NS release ________ onto post synaptic cell . This leads to ? |
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Definition
| ACh; slowing of heart rate |
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Term
| Ach __________ potassium permeability of cells and rate of potassium diffusion out of cells is _____________ |
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Definition
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Term
| Hyperpolarization of membrane occurs when |
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Definition
| potassium permeability is increased due to release of acetylcholine , and potassium diffuses out of the cell |
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Term
| Na channel activation takes longer due to? |
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Definition
| hyperpolarization of cell due to potassium leaving the cell because of acetycholine increasing the permeability of potassium across a cell wall |
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Term
| hormones that increase heart rate |
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Definition
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Term
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Definition
| decrease Ca , decrease contractility |
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Term
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Definition
| increase heart rate; spastic contractions |
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Term
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Definition
| blocks heart contraction by inhibiting calcium transport |
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Term
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Definition
| leads to heart block and cardiac arrest |
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