ATI TEAS (Test of Essential Academic Skills) Version 7ScienceMedium
A patient is admitted with severe muscle weakness, fatigue, and difficulty breathing. An EMG reveals impaired signal transmission at the neuromuscular junction. Which neurotransmitter, if deficient, would primarily account for these symptoms?
- AAcetylcholine
- BDopamine
- CGamma-aminobutyric acid (GABA)
- DSerotonin
Show answer & explanationAnswer & explanation
Correct answer: A. Acetylcholine
Acetylcholine is the primary neurotransmitter responsible for transmitting signals from motor neurons to muscle fibers at the neuromuscular junction. A deficiency or impaired function of acetylcholine would directly lead to muscle weakness and fatigue, including respiratory muscles.
Why the other options are wrong
- B. Dopamine is involved in mood, reward, and voluntary movement in the brain, but not directly at the neuromuscular junction.
- C. GABA is the main inhibitory neurotransmitter in the brain, reducing neuronal excitability, not directly involved in stimulating muscle contraction at the NMJ.
- D. Serotonin is involved in mood, sleep, and digestion, primarily in the CNS and gut, not neuromuscular transmission.
Neuromuscular Junction
The specialized synapse between a motor neuron and a skeletal muscle fiber, where nerve impulses are transmitted to muscle cells, causing contraction.
- Acetylcholine is the primary neurotransmitter released here.
- Binding of acetylcholine to receptors on the muscle fiber initiates muscle contraction.
- Disorders like Myasthenia Gravis affect this junction.
Memory trick: Neurotransmitters Navigate Nerves, Nudging New Actions.