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At the neuromuscular junction :...

At the neuromuscular junction ` : `

A

The muscle membrane possesses musculariae receptors

B

The motor nerve endings secrete norepinephrine

C

Curare leads to prolongationof neuromuscular transmission

D

The motor nerve endings secrete acetylcholine

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the neuromuscular junction, we will analyze each of the provided options step by step. ### Step-by-Step Solution: 1. **Understanding the Neuromuscular Junction**: - The neuromuscular junction (NMJ) is a synaptic connection between a motor neuron and a muscle fiber. It plays a crucial role in the transmission of signals from the nervous system to the muscles, enabling movement. 2. **Analyzing the Options**: - **Option 1**: "The muscle membrane possesses muscular adductors." - This statement is incorrect. The muscle membrane does not possess "muscular adductors"; instead, it contains acetylcholine receptors that respond to neurotransmitters. - **Option 2**: "The motor nerve endings secrete norepinephrine." - This statement is also incorrect. At the neuromuscular junction, the motor nerve endings secrete acetylcholine (ACh), not norepinephrine. Norepinephrine is associated with the sympathetic nervous system, not skeletal muscle activation. - **Option 3**: "Curare leads to prolongation of neuromuscular transmission." - This statement is incorrect. Curare is a neuromuscular blocking agent that prevents the transmission of nerve impulses to muscles, effectively blocking neuromuscular transmission rather than prolonging it. - **Option 4**: "The motor nerve endings secrete acetylcholine." - This statement is correct. At the neuromuscular junction, motor nerve endings release acetylcholine, which binds to receptors on the muscle membrane, leading to muscle contraction. 3. **Conclusion**: - Based on the analysis, the correct answer is **Option 4**: "The motor nerve endings secrete acetylcholine."
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