dorsal root ganglion

[yui_96]

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The following question is taken from Kaplan Biology Review Chapter 4 (The Nervous System).

"A surgeon accidentally clips a dorsal root ganglion during a spinal surgery. What is a likely consequence of this error?
I. Loss of motor function at that level
II. Loss of sensation at that level
III. Loss of cognitive function

So the answer given only includes II, but I wonder would I (loss of motor function) also be possible as if the pathway is severed at the preganglionic neuron, the postganglionic (motor) neuron wouldn't be functioning as well?

 

[DetroitDoc1993]

The Dorsal (posterior) Root is usually Somatic and Visceral Sensory (also known as afferent which is sensory). Whereas motor function comes from the Ventral (anterior) Root which can also be referred to as efferent (another way to say motor).

Technically the Dorsal and ventral roots do share "a street" before splitting to anterior and posterior Rami at the spinal ganglion but I think that might be beyond the scope of MCAT. The roots come out of the spinal cord separate and converge only to split to two different paths again. But the Dorsal Root and Ventral Root are both preganglionic themselves so unless the cut is made at the point where these two "streets" converge before splitting again, then cutting one root would not effect the other.

 

[Zenabi90]

My first reaction is "who cares." Second reaction: "this is med school type stuff already." Third reaction: "never once saw this on MCAT related stuff."

Bottom line: dorsal is sensory, ventral is motor. Dorsal has an S, sensory has an S. Ventral has a T, motor has a T.

MCAT doesn't write trick questions, and only assumes an undergraduate level of knowledge/understanding.

But if you want to go beyond, DetroitDoc has your answer for you.

Now if were talking Step 1......

 

[BBBallIsLife]

Literally just learned this in my anatomy class lol, after taking my mcat. Yeah, I agree with above. Don't stress over this. Kaplan...............I have no words