Question

Starting with release of ACh from the NMJ, arrange the events below in the order in which they would occur. I am not 100% sure about my answer here.

Starting with release of ACh from the NM), arrange the events below in the order in which they would occur. | 7 pts Binding of Ach to nicotinic receptors on motor endplate. Release of ACh from neuromuscular junction. Depolarization of muscle cell membrane. Binding of Ach to nicotinic receptors on motor endplate. Endplate depolarization Opening of cation-selective channels in motor endplate. Muscle contraction. Endplate depolarization. Opening of cation-selective channels in motor endplate. Depolarization of muscle cell membrane. Raised intracellular Ca2+ concentration. Raised intracellular Ca2+ concentration. Release of ACh from neuromuscular junction. Muscle contraction.

Answer 1

the Answer given by you is Right

1.Release of Ach from Neuromusular junction

(Ach are the neurotransmitters released from the pre synaptic Neuron)

2.Binding of Ach to nicotinic Receptors on motor end plate.

(motor end plates, are specialised chemical synapses formed at the sites where the terminal branches of the axon of a motor neuron contact a target muscle cell

Ach bindsto the Ach Receptors in the motor end plate)

3.Opening of Cations selective ion Channels in motor end plate.

When a nerve impulse releases the neurotransmitter acetylcholine from the nerve terminal, it binds to channel-shaped receptor molecules on the end plate, opening the channels and allowing positively charged sodium ions to flow into the muscle cell.

4.End plate Depolarization

End plate potentials (EPPs) are the voltages which cause depolarization of skeletal muscle fibers caused by neurotransmitters binding to the postsynaptic membrane in the neuromuscular junction

5.Depolarization of muscle cell membrane

The excitation of skeletal muscle by motor neurons causes the opening of voltage-gated sodium channels. The opening of sodium channels causes depolarization of the skeletal muscle. The action potential from the motor neuron also travels through the T-tubules.

6.Raised intracellular ca2+ concentration

( Depolarization causes opening of the voltage-gated (L-type) calcium channels)

7.Muscle contraction

Calcium remains in the sarcoplasmic reticulum until released by a stimulus. Calcium then binds to troponin, causing the troponin to change shape and remove the tropomyosin from the binding sites. Cross-bridge cling continues until the calcium ions and ATP are no longer available.