case entire Tve of the case se study writing Assignment #2: Muscles and Nervous
ID: 3508673 • Letter: C
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case entire Tve of the case se study writing Assignment #2: Muscles and Nervous : Ca blood work indicates that his extracellular potassium concentration is much suppose Kevin's pre-op than usua l. This condition is known as hyperkalemia and must be corrected before he can undergo ey.One of the dangers of hyperkalemia is that it makes neurons and muscle cells more excitable. Why does elevated extracellular potassium have this effect? Similar types of potassium channels are found in skeletal muscle cell (plasma) membranes. Predict the effect of general anesthesia on Kevin's skeletal muscle contraction during surgery. 7.Explanation / Answer
6.The potassium outflow hyperpolarizes the neuron by a normal process, in which the movement of positively charged K+ ions to the outside of the cell moves the interior-anchored voltage potential in the negative direction.
The normally present hyperpolarizing outflow of potassium is slowed down Less hyperpolarizing outflow is equivalent to depolarization, since there is a depolarizing inflow of sodium that was not also slowed down by an equivalent increase in intracellular sodium. The result is a change in the equilibrium potential of the cell.The increase in the membrane potential opens some of the sodium channels, which lets positive Na+ ions into the cell, further depolarizing it. This causes the neuronal excitable.
The effect of anesthesia on neuromuscular transmission by rendering the end-plate receptors by dereactive to the depolarizing effect of acetylcholine.
All agents caused an increase in the electric threshold of the muscle membrane and reduced or abolished the action potential. The rate of rise of an action potential was decreased by all agents.
These effects occurred without significant changes in the resting membrane potential of the muscle fibre and without a decrease in the transverse electric resistance of the muscle membrane.
It is suggested that these effects on the membrane threshold and on the action potential are due to a reduction of the selective sodium conductance change caused by an inactivation of the sodium carrying mechanism in the muscle membrane.
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