Q. 18 - Biology

Question

________ is released by motor nerve endings onto muscle. 

a. Acetylcholine 

b. Norepinephrine 

c. Dopamine 

d. Serotonin 

Step-by-Step Solution

Answer

Option a is the correct answer.

Step 1: Introduction

After the sympathetic nervous system (the typical adrenaline dump you experience after a "fight-or-flight" incident) is engaged, the parasympathetic nervous system restores organ function. Acetylcholine release affects target organs via lowering blood pressure, promoting digestion, and reducing heart rate.

Step 2: The explanation for the correct answer

Acetylcholine is released onto postganglionic neurons, which are ordinarily found relatively close to the target organs, by the axons of preganglionic neurons. Although some emit nitric oxide, the majority of postganglionic neurons release acetylcholine onto their intended target organs.

Step 3: The explanation for incorrect options

The rest of the options are irrelevant.