Exam 1: Lecture 6

Question 1

Describe the cellular characteristics of a motor end plate and include: synaptic vescicles, mitochondria, and dense bars

Answer 1

There are many mitochondria, synaptic vesicles release neurotransmitters via exocytosis with acetylcholine molecules, and dense bars anchored to the presynaptic membrane and associated with the synaptic vesicles

Question 2

Describe the characteristics of a motor end plate including: the synaptic gutter (trough), subneural clefts, and synaptic cleft

Answer 2

Synaptic gutter is a groove where the axon terminal makes contact with the sarcolemma, the subnerual cleft is a smaller cleft in the bottom of the trough, and the synaptic cleft is the narrow gap between the axon and the sarcolemma

Question 3

Describe the structure of an acetylcholine gated channel and include the subunits

Answer 3

These channels exist on the sarcolemma and consist of 2-alpha proteins, 1 beta protein, 1 gamma protein, and 1 delta protein

Question 4

Where are vesicles for neurotransmitters formed in the neuron and how are they transported

Answer 4

The vesicles are formed in the golgi aparatus and are transported via axonal transport and taken to the axon terminus and filled with Ach

Question 5

Compare the concentrations of calcium ion outside the axon and inside the axoplasm

Answer 5

There is a high concetration of calcium ions outside of the axon and less within the axoplasm

Question 6

How does calcium enter the axon during the transmission of an action potential?

Answer 6

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Question 7

State the number of acetylcholine molecules that attach to each ligand-gated channel

Answer 7

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Question 8

Define end-plate potential

Answer 8

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Question 9

Explain the steps in skeletal muscle contraction beginning with the release of acetylcholine from the neuron

Answer 9

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Question 10

List the mechanisms by which acetylcholine is removed from the synaptic cleft including the role of acetylcholinesterase

Answer 10

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Question 11

List the drugs that mimic acetylcholine that are not broken down by acetylcholinesterase and describe their effect on muscle contraction

Answer 11

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Question 12

List the drugs that inactivate acetylcholinesterase and describe their effect on muscle contraction

Answer 12

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Question 13

Describe the effect of curare on skeletal muscle contraction

Answer 13

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Question 14

Explain the process of the acetylcholine-gated ion channels

Answer 14

The tubular channel remains closed until two acetylcholine molecules attach to its alpha subunits