- A A direct, uninterrupted electrical connection that permanently couples the nerve cell membrane to the muscle cell membrane surface across the gap in standard practice under most conditions encountered
- B Synapse between motor neuron and muscle; acetylcholine released from nerve terminal binds nicotinic receptors on motor end plate, generating end-plate potential that triggers action potential in muscle
- C A thick myelin sheath layer that passively covers much of the outer surface area of the muscle fibre membrane in most vertebrate species as frequently observed in practice in many documented cases
- D A specialized gap junction structure that links together two separate adjacent skeletal muscle cell membranes electrically and chemically according to conventional understanding in routine practice
Correct answer: B. Synapse between motor neuron and muscle; acetylcholine released from nerve terminal binds nicotinic receptors on motor end plate, generating end-plate potential that triggers action potential in muscle
Explanation: NMJ: motor neuron terminal meets muscle fiber at motor end plate. Action potential in motor neuron → Ca2+ influx → acetylcholine (ACh) vesicle fusion → ACh diffuses across synaptic cleft → binds nicotinic ACh receptors → Na+ influx → end-plate potential → muscle action potential → Ca2+ release from SR → contraction.
Concept context
Types of movement, muscle contraction, skeletal system, joints, and disorders. Important for Class 11 and NEET.