Term
| The outermost muscle layer that surrounds the heart |
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Definition
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Term
| Name the middle muscular layer of the heart |
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Definition
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Term
| Name the inner layer of the Heart |
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Definition
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Term
| What is the Myocardium composed of? |
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Definition
| Unbundled contractile muscle fibers |
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Term
| An electrical charge caused by the condition of ions across a membrane is termed |
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Definition
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Term
| What nervous system is responsible for stimulation of the myocardial tissue? |
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Definition
| Sympathetic Nervous System |
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Term
| The myocardium is composed of two proteins filaments named: |
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Definition
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Term
True or False
Cross-bridges stick out from actin filaments to interact with myosin filaments so the contraction will take effect |
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Definition
False
The Cross-Bridges stick out from myosin filaments to interact with actin during contraction |
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Term
| The segment of a myofibril that extend from one Z line to the next is called: |
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Definition
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Term
| What are the structures that connect the muscle fibers? |
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Definition
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Term
| What are the structures found inside the Intercalated Disks? |
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Definition
| Gap Junctions and Desmosomes |
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Term
| Name the small channels or connections between cells that are filled with cytoplasma and facilitate the rapid spread of action potential so the cells work in unison as one |
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Definition
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Term
| Name the plasma membrane that surrounds the muscle fibers |
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Definition
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Term
| Name the small connections between the cells that act like cement and hold the cells together |
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Definition
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Term
| The lines that separate one sarcomere from the next are called: |
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Definition
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Term
| Name the darker area within the sarcomere that contains mostly thick filaments, but also has overlapping thin filaments |
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Definition
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Term
| A narrow zone in the middle of the A-Band that contains thick(myosin) filaments only, is called: |
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Definition
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Term
| A lighter area that surrounds the Z-Lines is called |
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Definition
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Term
| Invaginations or tunnel like infoldings of the sarcolemma that penetrate the muscle fibers are called |
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Definition
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Term
| Organelle that is the powerhouse of the cell, which is seen more in the heart muscle than in the skeletal muscle fibers |
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Definition
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Term
| What does Mithocondria generate? |
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Definition
| It generates ATP, used to fuel fiber contraction |
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Term
| Name the cell component that acts as a storage house for cytoplasm and Ca++, surrounding each myofibril and releasing Ca++ for myocardium contraction |
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Definition
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Term
| What removes the Ca++ from the cytoplasm after contraction occurs, so that the muscles can relax? |
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Definition
| Calcium Active Transport Pump |
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Term
| Where are Calcium Active Transport Pumps stored? |
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Definition
| In the Sarcoplasmic Reticulum |
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Term
| What is the cell component that contains DNA and controls cell activities? |
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Definition
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Term
| Which three ions are involved in Action Potential? |
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Definition
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Term
| Which of the three ions is responsible for firing the myocardium? a)Sodium (Na+) b)Potassium (K+) c)Calcium (Ca++) |
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Definition
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Term
| Which ion is responsible for contracting the myocardium? |
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Definition
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Term
| Which ion is responsible for relaxing the myocardium? |
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Definition
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Term
| Name the phase that is caused by the Na+ ions rapidly flowing into myocytes through fast-gated Na+ channels |
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Definition
| Rapid Depolarization (Phase 1) |
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Term
| What is the resting potential of the muscle fibers before contraction occurs? |
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Definition
-90 mV The voltage changes from -90mV to +30mV forming Rapid Depolarization(Phase 1) |
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Term
| Name the phase in which Ca++ slowly moves into the cell through slow Ca++ channels, initiating cardiac muscle contraction |
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Definition
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Term
| For how long does Depolarization (contraction) occur? |
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Definition
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Term
| Name the phase in which K+ flows out of the cell and the cardiac muscle begins to relax? |
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Definition
| Relaxation Phase or Repolarization Phase (Phase 3) |
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Term
| For how long does Repolarization (relaxation) occurs? |
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Definition
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Term
| Name the phase in which Na+ moves out of the cell and K+ moves in so that the membrane potential can be readied for another excitation |
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Definition
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Term
| If a cell were stimulated during this time frame, it would not be excitable. What is the name of this period and during what phase does it occur? |
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Definition
| It is called "Absolute Refractory Period" or "Effective Refractory Period", and it occurs from onset of Phase 1 until the middle of Phase 3 [image] |
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Term
What is the duration time of "Absolute Refractory Period"? |
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Definition
| It lasts approximately as long as the muscle action potential, which is about 250milliseconds (0.25 sec) |
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Term
| Name the period in which the myocardium can be excited again so another action potential can occur, and when does this period occur? |
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Definition
| It occurs during resting time (Phase 4), and it's called "Relative Refractory Period" |
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Term
| What is the total time of contraction and relaxation of the muscle? |
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Definition
| 300 milliseconds or 0.3 sec (Phase 1, 2, and 3, but not Phase 4, which is the resting time) |
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Term
| The sarcomere shortens due to action of the actin filaments sliding over the myosin filaments. This will result in muscle contraction, and the theory is called: [image] |
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Definition
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Term
| What are the two proteins that are part of the thin filaments-actin? |
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Definition
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Term
| What must be present and bind to the troponin to cause the movement of tropomyosin, so myosin and actin can interact together to produce contraction of the muscle? |
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Definition
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Term
| What is required to release the myosin's head from the actin filament? |
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Definition
| The breakdown of ATP to ADP |
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Term
| What protein covers the active sites of actin? |
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Definition
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Term
| What cases the tropomyosin to uncover the actins' active site allowing myosin to interact with actin? |
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Definition
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Term
| Name the theory which states that myosin must act with actin in order to have muscle fiber shortening |
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Definition
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