PrepTest 152

The success is related to the survival of the nerve sheath, which depends on the presence of living tissue, not the speed of the nerve growth. If a motor nerve is severed 100 mm from the muscle it controls, it doesn't matter if the speed of regrowth is 1 mm or 2 mm, unless something keeps the intervening tissue alive.

There's nothing to indicate that the disintegration of a nerve sheath can be reversed. Living tissue can prevent it from disintegrating, but prevention isn't the same as reversing.

If living tissue is in the sheath, the three-month deadline doesn't seem to apply. Also, assuming there is no living tissue, the nerve sheath will start to disintegrate and the nerve cell won't regenerate, but if you're going to law school, you probably don't have a medical degree and don't know if there's another way to restore motor function!

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
Ouch! Motor nerves die when severed, but they regrow slowly and at a set rate. To do so, they need the nerve sheath. This sheath disintegrates within a few months without living tissue in it.

Answer Anticipation:
There's a lot of overlap between these statements, so any anticipation here would be as likely to be a complete miss as something that is close to the correct answer. It's more important in this case to understand the statements and not get confused by the scientific language.

Answer Explanation:
First off, this answer is very weak, making it easier to support. For example, the last section states this answer only must be true in some cases for it to be supported. Additionally, we are told that living tissue will keep the nerve sheath alive past three months, making it at least possible for the motor nerve to regenerate, which is a higher possibility than 0%.

Key Takeaway:
When a Must Be True question doesn't ask for absolute certainty (e.g., most strongly supported), the correct answer will frequently use very weak language. Additionally, get rid of answers that bring in ideas not mentioned by the author.

Surgical intervention? Again, if you don't have a medical degree, you don't know what's needed to keep that nerve sheath alive. Maybe some gingko biloba will keep the tissue alive.