Term
|
Definition
Intercalated discs
-Look like stairs
-Interdigiting folds of sarcolemma at end of adjacent cells
-Link cells structurally and functionally |
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Term
| Structure of Cardiac Muscle |
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Definition
-1 or 2 centrally located nuclei
-Cross striations- sarcolemma and myofibrils
-Branched
-Cylindrical
-Lipofuscin granules
-Store lots of glycogen |
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Term
| 2 Parts of Intercalated Disc |
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Definition
-Transverse portion
-Longitudinal portion |
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Term
|
Definition
-Adherins- like Z-line; connect thin filament to terminal sarcomere
-Desmosomes- bind cells together; keep from separating in contraction |
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Term
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Definition
-Gap junctions:
1. ionic continuity
2. Ionic coupling
3. Spread of depolarization |
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Term
| Major Histological Differences b/t Cardiac and Skeletal Muscle |
|
Definition
1. Diad instead of Triad
2. Mitochondria
3. Myofibrils |
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Term
|
Definition
-1 terminal cisterna
-Larger
-Located near Z-line
-Lined by external lamina |
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Term
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Definition
| Greater and more numerous |
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Term
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Definition
| Not fully separated due to less developed sarcoplasmic reticulum |
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Term
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Definition
-Initiate, regulate, coordinate heart beat
-Found at SA and AV nodes, Bundle of His, Purkinje fibers
-Para/Sympathetic nerves that terminate at the nodes ONLY MODIFY the intrinsic contraction |
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Term
|
Definition
-Location: atrial wall and interventricular septum
-Action: produce small peptide hormones like atrial natriuretic polypeptide-->DECREASE BP |
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Term
|
Definition
-NO REGENERATIVE CAPACITY
-Dead cells replaced with connective tissue |
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Term
| Autonomic nervous system modify cardiac function by regulating: |
|
Definition
a. Automaticity
b. Force of contraction |
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Term
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Definition
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Term
|
Definition
| -Atrial and ventricular muscles |
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Term
| Slow-Response Pacemaker Action Potential Phases |
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Definition
0- depolarization
3- repolarization
4- pacemaker potential/slow depolarization |
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Term
| Slow/Pacemaker AP generation |
|
Definition
0.-L type Ca channels open via DHPR-->Ca influx (depol.)
3.-L type Ca close; K open-->K efflux (repol.)
4- K close
-Funny open-->Na influx (slow/pacemaker)
-T-type Ca open- Ca influx (slow/pacemaker) |
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Term
| What is necessary for cardiac muscle contraction? |
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Definition
Calcium induced calcium release
AP in T-tubule-->DHPR and L-type Ca open-->Ca enter cell-->Ca binds to RyR-2R releasing calcium to bind to troponin C |
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