Neuromuscular Junction Steps Flashcards

Questions and Answers

What happens in step 1 of the neuromuscular junction process?

An action potential travels down the axon.

What occurs in step 2 of the neuromuscular junction process?

Calcium channels open and calcium enters the axon terminal.

What is caused by calcium entering the axon terminal in step 3?

Calcium entering causes vesicles to release AcH via exocytosis.

In step 4, where does ACh diffuse to?

ACh diffuses across the synaptic cleft and binds to ACh receptors on the junctional folds of the motor end plate. Signup and view all the answers

What happens in step 5 regarding sodium channels?

Sodium channels open and sodium crosses the sarcolemma entering the muscle fiber. Signup and view all the answers

What occurs inside the muscle fiber during step 6?

The inside of the muscle fiber becomes more positive (depolarization). Signup and view all the answers

Describe step 7 in the neuromuscular junction.

An action potential travels across the sarcolemma. Signup and view all the answers

What happens in step 8 regarding ACh activity?

ACh activity is terminated when it is broken down by AcHe into acetyl and choline which cannot activate ACh receptors. Signup and view all the answers

What is the purpose of the diffusion of acetylcholine as stated in step 8 A.K.A?

Diffusion of acetylcholine. Signup and view all the answers

What is the definition of depolarization in muscle fibers?

Inside of the muscle fiber becomes more positive. Signup and view all the answers

Study Notes

Steps of Neuromuscular Junction Transmission

An action potential travels down the axon, initiating the neuromuscular transmission process.
Calcium channels in the axon terminal open, allowing calcium ions to enter and trigger subsequent reactions.
The influx of calcium ions causes synaptic vesicles to release acetylcholine (ACh) into the synaptic cleft through the process of exocytosis.
ACh diffuses across the synaptic cleft and binds to acetylcholine receptors located on the junctional folds of the motor end plate.
When ACh binds to its receptors, sodium channels open, permitting sodium ions to cross the sarcolemma, which leads to muscle fiber excitation.
The entry of sodium ions results in depolarization, where the inside of the muscle fiber becomes more positive.
Following the depolarization, an action potential is generated and travels across the sarcolemma, further stimulating muscle contraction.
The activity of ACh is terminated by the enzyme acetylcholinesterase (AChE), which breaks ACh into acetyl and choline, preventing further activation of ACh receptors.
Acetylcholine can also diffuse away from the synaptic cleft, contributing to its termination.

Description

Test your understanding of the steps involved in the neuromuscular junction process with these flashcards. Each card highlights a specific step, from the arrival of an action potential to the binding of acetylcholine to its receptors. Perfect for students of biology and neuroscience.