Question 32
NECO_MODEL_QUESTIONS_VOL1
•
2021
•
BIOLOGY
•
objective
During a sudden forward pull on a weight‑lifting bar, the muscle spindle in the biceps is stretched. Describe the reflex arc that is activated, the neurotransmitter released at the neuromuscular junction, and the immediate effect on the biceps muscle tension.
Answer Options
Correct Answer
A.
The stretch reflex is triggered: Ia afferents → monosynaptic excitation of the alpha‑motor neuron → acetylcholine released at the neuromuscular junction → contraction of the biceps, increasing tension.
B.
The stretch reflex is triggered: Ia afferents → monosynaptic excitation of the alpha‑motor neuron → acetylcholine released at the neuromuscular junction → contraction of the triceps, increasing tension.
C.
The stretch reflex is triggered: Ib afferents → polysynaptic inhibition of the alpha‑motor neuron → acetylcholine released at the neuromuscular junction → relaxation of the biceps, decreasing tension.
D.
The stretch reflex is triggered: Ia afferents → monosynaptic excitation of the gamma‑motor neuron → norepinephrine released at the neuromuscular junction → contraction of the biceps, increasing tension.
Correct Answer
A
Correct Option:
The stretch reflex is triggered: Ia afferents → monosynaptic excitation of the alpha‑motor neuron → acetylcholine released at the neuromuscular junction → contraction of the biceps, increasing tension.
About This Question
This is
Neco Model Questions Vol1
2021
Biology
Question 32.
It is one of the
objective
questions from the
2021
Neco Model Questions Vol1
Biology
examination.
Difficulty level:
Medium
.