×TI Course: K?N 0258-01-X? amoodley Downloads Lectu e%20Study%20Guide%20Ch%209%2
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×TI Course: K?N 0258-01-X? amoodley Downloads Lectu e%20Study%20Guide%20Ch%209%20Mu cie%20Part%201%20 f 202%20(1).pdf Muscle: Intro to Huma × y D Lecture Study Guide c?D Lecture Study Gade-x Yo Lecture Content Questions 1. What does it mean to say that a cell is electrically excitable? 2. What happens to membrane potential during an action potentialt? 3. What is the general function or purpose of muscle tissue? How does muscle tissue contribute to homeostasis? Describe four properties (characteristics) of muscle tissue. Muscle tissue both receives signals from the CNS via neurons and sends signals to the CNS via neurons. Describe afferent and efferent signals as they pertain to skeletal muscle cells What are proprioceptors and how do they contribute to homeostasis? 4. 5. 6. 7. Describe how an action potential in a motor neuron leads to the generation of an action potential in a skeletal muscle cell. Iinclude the following terms: synaptic end bulb, voltage-gated Ca2, ion channels, exocytosis, AC, ACh receptors, ligand-gated ion channels, flux of lons across the plasma membrane of the muscle cell. 8. What are T-tubules and what role do they play in excitation-contraction coupling? 9. What is the sarcoplasmic reticulum? What is it made of? What is its function or purpose? 10. How does the sarcoplasmic reticulum change in response to an action potential i.e, the cell was at rest, then an action potential arrives)? How does the sarcoplasmic reticulum change when an 11. A resting muscle cell has very little Ca in the cytosol. Why? What makes that so? Explain the 12. A contracting muscle ell has relatively high concentration of Ca2 in the cytosol. Why? What action potential stops fi.e., the cell is no longer stimulated and returns to rest)? role of calcium pumps and ATP makes that so? Explain the role of calcium release channels. 13. What is the role of calcium in the contraction cycle? 14. What are myofibrils? Where in the cell do they occur? What are they composed of? What is their general function or purpose? 15. Draw a thick filament and label the following: myosin, myosin heads, myosin tails 16. During the contraction cycle, the protein myosin undergoes a conformational change. Draw a molecule of myosin in the "low energy" conformation and in the "high energy" conformatiorn. 17. What must occur in order for myosin to change shape, from the ?0wenergy" to the "high energy" conformation? 18. Draw a thin filament and label the following: actin, myosin binding sites (on actin), troponin, MacBook AirExplanation / Answer
1. For a cell to be excitable, it refers to the ability of some cells to be stimulated resulting in the generation of action potentials. Examples include neurons, muscle cells.
2. Action potential causes the membrane potential of a specific axon to rapidly fall and rise. This depolarisation then causes adjacent locations to similarly depolarise.
3. There are three types of muscle tissue namely skeletal, cardiac and smooth. They are associated with different functions such as providing structural support, locomotion , housekeeping functions, production of heat etc.
The muscular systems interact with all other systems of the body to promote and maintain homeostasis. For example, the smooth muscle near the blood vessels constrict near the skin surface thus reducing the amount of blood near the surface of the skin to conserve heat. In case of cold, shivering produces random skeletal contractions which generate heat acting as a part of negative feedback mechanism to maintain body temperature.
4. The muscle tissue has four characteristics namely:
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