Sage-Tips

What is the effect of acetylcholine on the postsynaptic neuron?

Binding of acetylcholine to its receptors on the postsynaptic cell opens up ligand-gated sodium channels. These allow an influx of Na+ ions, reducing the membrane potential. This reduced membrane potential is called an excitatory postsynaptic potential or EPSP.

What happens to acetylcholine after its function is complete?

Acetylcholine is rapidly destroyed by the enzyme acetylcholinesterase and thus is effective only briefly. Inhibitors of the enzyme (drugs known as anticholinesterases) prolong the lifetime of acetylcholine.

What happens to acetylcholine after it has acted on the muscle?

The acetylcholine molecules then bind to nicotinic ion-channel receptors on the muscle cell membrane, causing the ion channels to open. Sodium ions then flow into the muscle cell, initiating a sequence of steps that finally produce muscle contraction.

How does acetylcholine cause depolarization at the post synaptic neuron?

The binding of ACh to its receptors produces a conformational change in a membrane channel that is specifically permeable to both Na+ and K+. As a result of an increase in Na+ and K+ permeability, there is a depolarization of the postsynaptic membrane.

What happens after acetylcholine binds to its receptors?

When acetylcholine binds to acetylcholine receptors on skeletal muscle fibers, it opens ligand-gated sodium channels in the cell membrane. Sodium ions then enter the muscle cell, initiating a sequence of steps that finally produce muscle contraction.

What happens to acetylcholine after it is released from the presynaptic membrane?

What happens to acetylcholine (ACh) after it is released from the presynaptic membrane? ACh is broken down and the choline is reabsorbed.

What receptor does acetylcholine bind to in the neuromuscular junction that then results in the contraction of skeletal muscle?

nicotinic acetylcholine receptor
Acetylcholine receptors In vertebrates, the acetylcholine receptor subtype that is found at the neuromuscular junction of skeletal muscles is the nicotinic acetylcholine receptor (nAChR), which is a ligand-gated ion channel.

What role does acetylcholine play in muscle contraction quizlet?

What is the role of acetylcholine in a skeletal muscle contraction? Acetylcholine binds to receptors in the motor end plate, initiating a change in ion permeability that results in the end-plate potential.

How is acetylcholine removed from the synaptic cleft?

Acetylcholine is removed from the synaptic cleft by an specialized enzyme located in the synaptic cleft called acetylcholinesterase (AChE).

What happens after the acetylcholine binds to the acetylcholine receptor on the motor end plate?

As acetylcholine binds at the motor-end plate, this depolarization is called an end-plate potential. It then spreads along the sarcolemma, creating an action potential as voltage-dependent (voltage-gated) sodium channels adjacent to the initial depolarization site open.

What happens after the acetylcholine binds to the acetylcholine receptor on the muscle fiber?

The acetylcholine binds to the nicotinic receptors concentrated on the motor end plate, a specialized area of the muscle fibre’s post-synaptic membrane. This binding causes the nicotinic receptor channels to open and let sodium ions enter the muscle fibre.

What is the mechanism of action of acetylcholine?

Acetylcholine’s interaction with muscarinic receptors, as with nicotinic receptors, causes channels to open resulting in ion flow that depolarizes the muscle cell. As in skeletal muscle, the depolarization leads to muscle contraction. Like smooth muscle, cardiac muscle has muscarinic receptors.

How do neurotransmitters trigger action potentials in neurons?

These neurotransmitter molecules bind to the receptors on the postsynaptic membrane, triggering action potential in the postsynaptic neuron by causing changes in permeability of certain ions. This mechanism is common to all neurotransmitters with a few or more variations.

How does a motor neuron make contact with a muscle cell?

A motor neuron contacts a muscle cell at a structure called a motor end plate. The muscle cell membrane contains nicotinic receptors that are sensitive to acetylcholine. These receptor molecules, made of protein, are concentrated where acetylcholine is released. The nicotinic receptor is a ligand-gated sodium channel.

What happens to neurotransmitters when they reach the synaptic knob?

When an impulse reaches the synaptic knob, synaptic vesicles within fuse with the synaptic membrane, causing the release of neurotransmitter molecules into the synaptic cleft.