You measure levels of Ca²⁺ in various locations within a motor neuron and a skeletal muscle fiber when the motor neuron is NOT depolarized, and the muscle fiber is at rest. Where do you expect to find high levels of Ca²⁺?

Question

Quizplus · Accepted Answer

Ca²⁺ is calcium ions stored in the sarcoplasmic reticulum of the muscle fiber. In a resting state, high levels of Ca²⁺ are expected to be found within the sarcoplasmic reticulum. Option A is incorrect because vesicles within the motor neuron store neurotransmitters and not Ca²⁺. Option B is incorrect because Ca²⁺ is not typically found in the cytosol of the motor neuron terminus. Option C is incorrect because Ca²⁺ is not typically found in the synaptic cleft in a resting state.

You Measure Levels of Ca2+ in Various Locations Within a Motor

You Measure Levels of Ca²⁺ in Various Locations Within a Motor