PT152.S1.Q22

PrepTest 152 - Section 1 - Question 22

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Although severing a motor nerve kills part of the nerve, it can regenerate, growing about 1 millimeter per day from the point of damage toward the muscle the nerve controlled. ███ ███ ████████ █ ███████ █████ █████ ████ ██████████ █ ████ ██████ ████████ █ ████ ██████ ████ ██ ██████████ ██ ████ █████ ██ ███████ ██ ███ ████████ ██████ ████ ██ ███ ██████ ████████████ ███ ███████ █████ ███████ ███ ████████ █████ ██████ ██ █████ ████ ██ ███ ████ ████ ███ ████ █████████ ███ ████ ██████ ██████ ██ ████████████ █████ █████ █████ ██████ ██████ █████ ██ ██████ █████ ██████ ██████ ███

Summary

Severing a motor nerve kills part of the nerve. However, the nerve can regenerate. When regenerating, a nerve grows about 1 millimeter every day from the point of severing toward the muscle the nerve controlled. For example, a severed nerve controlling a hand would take longer to regenerate if the nerve was severed at the shoulder compared to the wrist.

Growing nerve cells also require the original nerve sheath to guide them to the muscle. However, the original nerve sheath disintegrates after three months unless living nerve tissue exists within it.

Strongly Supported Conclusions

If a severed motor nerve would take more than three months to regenerate, it is unlikely to reconnect to its muscle.

If an severed motor nerve's original sheath contains living nerve tissue, then the likelihood that the nerve can successfully regenerate even after three months increases.

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22.

The statements above, if true, ████ ████████ ███████ █████ ███ ██ ███ ██████████

a

Doubling the speed ██ █████ ███ █████ █████ ████ ████ ██████ ███ ██████████ ████ █ ███████ █████ █████ ████ █████ ███ ██████ ██ ███ ███████████

b

It is sometimes █████████ ████ █ █████ ██████ ███ █████ ██ █████████████ ██ ███████ ██ ████ ███ ███████ ██ ███████████████

c

If a severed █████ █████ ████ ███ ██████████ ████████████ ██████ █████ ██████ █████ █████ ████████ ███████████ ██████ ██ ████████ ██ ███ ██████ ████ ███ █████ ███ ███████████

d

If living nerve ██████ █████ ██ █████████ ███ █████████ ██████ ███ ████████ ██████ ██ █ ███████ █████ ██████ ███ ██████████ ████ ███ █████ ████ ██████████ █████ ████████ ██ ████ ██████

e

Without surgical intervention, █ ██████ ████ ███ ████ ████████ ███████ ██ █ ███████ █████ █████ ██ ████████ ██ ██████ ████ █████████

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