Term
| The fibers than conduct the impulse to the left atrium from the SA node. |
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Definition
| What is Bachmann's Bundle? |
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Term
| Prevents direct excitation of the ventricles. |
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Definition
| What does the fibrous AV ring do? |
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Term
60 100 60 atria, av node and septum, ventricles |
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Definition
| What is the conduction velocity of the heart? Give the break down. |
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Term
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Definition
| AV node is depolarized by ____ channels. |
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Term
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Definition
| What is the rate of spontaneous depolarization of the AV node? |
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Term
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Definition
| What is the rate of the spontaneous depolarization of the SA node? |
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Term
right, right bundle branch block |
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Definition
| Bundle of His passes along the ____ side of the septum and becomes the _____. |
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Term
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Definition
| Purkinje fibers have extremely ____ conduction. |
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Term
| septum and papillary muscles |
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Definition
| What are the first 2 regions of the ventricle to be activated? |
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Term
bundle branches and purkinje fibers AV node |
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Definition
| Conduction is fastes in what 2 areas? and slowest in what area? |
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Term
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Definition
| Ischemic or structural damage will produce ____. |
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Term
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Definition
| Other potential pacemakers are suppressed by _____. |
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Term
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Definition
| What is the spontaneous depolarization of the Bundle of His |
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Term
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Definition
| What is the spontaneous depolarization of the purkinje fibers? |
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Term
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Definition
| Phase 4. What is the resting membrane potental of a cardiac myocyte? This is due to high ___ conductance |
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Term
depolarization inward Na+ current |
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Definition
| what is phase 0, cardiac myocyte? Due to what? |
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Term
| partial rapid repolarization due to stopping Na+ in and getting K+ out |
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Definition
what is phase 1? due to what 2 things? |
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Term
| plateau phase due to the balance of K+ out and Ca+in |
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Definition
| what is phase 2? due to what balance? |
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Term
| repolarization due to the increase of K+ out |
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Definition
| what is phase 3? due to what? |
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Term
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Definition
Phase 0 is mediated by _____ gated ion channels. At rest the activation gate is ____ and the inactivation gat is ______. |
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Term
inactivation gates this prevents another depolarization. |
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Definition
| In phase 0, what gates rapidly close upon depolarization? what does this do? |
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Term
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Definition
| Ca+ current in the heart is mainly thru what type Ca+ channels? |
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Term
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Definition
| Ca+ entering the cell induces _____ from the SR. |
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Term
Ca+ channel blocker effective for HTN pts |
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Definition
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Term
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Definition
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Term
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Definition
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Term
Ca+ channel blockers used to treat arrhythmias |
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Definition
Verapamil what is it good for? |
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Term
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Definition
| The Ik (transient outward) current referrs to what phase? It is rapidly activated and inactivated in this phase. |
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Term
| The Ik (slow) and the Ik (rapid) make it up and it contributes to phase 3 repolarization. |
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Definition
What is the delayed rectifier current? And what phase does it correspond to? |
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Term
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Definition
| Bottom line in cardiac myocytes: Efflux of what ion causes repolarization? |
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Term
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Definition
| Absolute refractory periods lasts until what voltage? |
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Term
| AP can be generated but not conducted. |
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Definition
| What is effective refractory period? |
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Term
-70mV stronger stimulus is required to produce an AP |
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Definition
| Relative refractory period is at what voltage? also define. |
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Term
very brief period when Na+ channels can be activated and repolarization is not complete cell is closer to threshold and it is easier to excite. |
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Definition
| what is the supranormal refractory period? |
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Term
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Definition
| What is the threshold in an nodal cell? |
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Term
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Definition
| What is the max repolarization for a nodal cell? (normally) |
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Term
blocks the If and is in clinical trials for angina and CHF |
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Definition
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Term
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Definition
| Parasympathetic innervation of the heart |
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Term
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Definition
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Term
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Definition
| If GIRK goes up, HR goes _____. |
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Term
Isoproternol - Beta agonist increase If Atropine - decreases GIRK to increase HR |
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Definition
| What are 2 drugs that will raise the HR? How? |
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Term
If is decreased due to reduced cAMP production. GIRK is increased and more K+ intracellularly. Decreased inward Ca++ channels. Increased the conduction velocity thru the AV node. |
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Definition
Increased vagal activity will slow HR by 3 mechanisms... Vagal stimulation also has a negative dromotropic effects via... |
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Term
Increase of Na+ current to increase If Increase of Ca++ Increase of K+ (faster repolarization) All 3 increased by cAMP phosphorylation via stimulation of adenlyly cyclase by Gs protein. Also increases conduction velocity thru the AV node. |
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Definition
Sympathetic will increase HR in 3 ways when NE binds to beta receptors at the SA node... all work via _____ (mechanism of action of Beta) also has a dromotrophic effect at the ____. |
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