Question

Muscular System: Neuromuscular Junction

1. Synaptic vesicles in the axon terminal of a motor neuron contain what neurotransmitter? _________________________

2. Match the following three terms with their definitions:

1. Terminal cisternae

2. T tubules

3. Sarcolemma

____ plasma membrane of muscle cell

____ part of sarcolemma—carries action potential

____ part of sarcoplasmic reticulum—stores calcium ions

3. An action potential in the axon terminal of a motor neuron opens what type of ion channels? _________________________

4. By what means of membrane transport does the neurotransmitter leave the axon terminal? _________________________

5. Binding of neurotransmitter to the receptors on the motor end plate opens what type of ion channels? _________________________

6. Opening of these channels leads to _________________________ of the motor end plate.

7. How is the neurotransmitter removed from the synaptic cleft?

8. As a result of question 6, an action potential is propagated along the _________________________ of the muscle cell and down the _________________________ into the cell.

9. The result of this action potential releases what ion from the terminal cisternae? _________________________

Answer 1

1.Acetyl choline

2. Terminal cisternae- Part of sarcoplasmic reticulum- stores calcium ions

T tubules- part of sarcoplasmic reticulum- carries action potential

Sarcolemma- plasma membrane of muscle cell

3. Voltage gated Ca2+ channels.

4. Exocytosis - it is a type of active transport in which the cell transport molecules out of the cell by secreting them

5. Ligand gated ion channels

6.Depolarisation

7. Neurotransmitter is removed from the synaptic cleft by two mechanisms: 1) degraded by the enzyme acetyl cholinesterase. 2) reabsorbed with the help of a transport protein present on the presynaptic membrane.

8. An action potential is propogated along the sarcolemma of the muscle cell and down the t-tubules into the cell

9.Calcium ions