Term
| what does "intrinsic" mean? |
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Definition
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Term
| what does "extrinsic" mean? |
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Definition
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Term
| What is "Cardiac Automaticity"? |
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Definition
| Heart is able to initiate its own rhythmic contractions w/o requiring a stimulation from outisde the heart. |
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Term
| What is "Cardiac Automaticity" caused by? |
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Definition
| Cardiac Automaticity is caused by "leaky" cell membranes, in which calcium & sodium ions slowly leak into the cells. this leaking causes a slow depolarization to threshold, thus firing an action potential & initiating contractions of cardiac muscle. |
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Term
| The cells that are most "leaky" to oins & that depolarize fastest constrol the rate of contraction of all other cardiac cells; thus, they act as pacemakers for the rest of the heart. What is the pacemaker of the heart called? |
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Definition
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Term
| What is the Sinoatrial node? |
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Definition
| A group of specialized cells near the junction of the vena cava and the right atrium. (The Sinoatrial node is present in mammalian hearts, in comparison to frogs, for example.) |
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Term
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Definition
| Contraction period of the heart |
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Term
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Definition
| Relaxation period of the heart |
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Term
| What is the "contraction period" of the rhythmic cycle that atria & ventricles are synchronized to? |
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Definition
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Term
| What is the "relaxation period" of the rhythmic cycle that atria & ventricles are synchronized to? |
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Definition
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Term
| What is the "Sinoatrial node" equivalent in the frog's heart during lab? |
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Definition
| "Sinus Venosus" is equivalent to the Sinoatrial node found in mammalian hearts |
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Term
| Can the heart still beat with the Central Nervous system destroyed? |
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Definition
| Yes, it is controlled by intrinsic mechanisms |
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Term
| what is "positive chronotropic"? |
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Definition
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Term
| what is "positive inotropic"? |
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Definition
| strength increasing (heart) |
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