Physio Ex Exercise 3 Activity 8 PDF

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2/9/2021

PhysioEx Exercise 3 Activity 8

PhysioEx Lab Report Exercise 3: Neurophysiology of Nerve Impulses Activity 8: Chemical Synaptic Transmission and Neurotransmitter Release Name: Natalie Villarreal Date: 9 February 2021 Session ID: session-8d214b1e-7f2d-e331-9477-48cdc6b75fcf

Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 1 The end of the axon where it contacts a target is called the You correctly answered: axon terminal. 2 Neurotransmitter is released into the synaptic gap by You correctly answered: exocytosis. 3 Exocytosis of neurotransmitter from the axon terminal is triggered by an increase in the intracellular concentration of You correctly answered: Ca 2+. 4 Neurotransmitter released into the synaptic gap reaches the target cell by You correctly answered: diffusion. 5 At the target, neurotransmitter You correctly answered: does all of the above.

Experiment Results Predict Questions 1 Predict Question 1: You have just observed that each action potential in a burst can trigger additional neurotransmitter release. If calcium ions are removed from the extracellular solution, what will happen to neurotransmitter release at the axon terminal? Your answer: There will be less neurotransmitter release. 2 Predict Question 2: What will happen to neurotransmitter release when low amounts of calcium are added back to the extracellular solution? Your answer: Neurotransmitter release will increase a small amount. https://media.pearsoncmg.com/bc/bc 0media ap/physioex/10/ex3/act8/

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2/9/2021

PhysioEx Exercise 3 Activity 8

3 Predict Question 3: What will happen to neurotransmitter release when magnesium is added to the extracellular solution? Your answer: There will be no neurotransmitter release. Stop & Think Questions 1 Why does the stimulus intensity affect the amount of neurotransmitter release at the axon terminal? You correctly answered: Both "The stimulus intensity directly affects the amount of calcium entering the axon terminal." and "The stimulus intensity proportionally affects the number of synaptic vesicles that discharge their contents into the synaptic cleft." are correct. 2 Why is there no neurotransmitter release from the axon terminal when there are no calcium ions in the extracellular solution? You correctly answered: Exocytosis of the synaptic vesicles is calcium dependent. 3 Why did the high intensity stimulation fail to trigger the same amount of neurotransmitter release in the presence of extracellular Mg 2+ as in the control extracellular solution? You correctly answered: Mg 2+ blocks the calcium channels in the axon terminal.

Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1 How is the neurotransmitter stored in the axon terminal before it is released? You correctly answered: contained in synaptic vessicles. 2 Are neurotransmitter molecules released one at a time or in packets? You correctly answered: in packets. 3 With the normal extracellular calcium concentration, [Ca 2+], when the action potential reaches the axon terminal it triggers You correctly answered: release of neurotransmitter by exocytosis. 4 Comparing the low intensity stimulus to the high intensity stimulus, the high intensity stimulus causes You correctly answered: more synaptic vesicles to undergo exocytosis.

Review Sheet Results i https://media.pearsoncmg.com/bc/bc 0media ap/physioex/10/ex3/act8/

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PhysioEx Exercise 3 Activity 8

1 When the stimulus intensity is increased, what changes: the number of synaptic vesicles released or the amount of neurotransmitter per vesicle? Your answer: Increasing stimulus intensity increases the number of synaptic vesicles released. 2 What happened to the amount of neurotransmitter release when you switched from the control extracellular fluid to the extracellular fluid with no Ca 2+? How well did the results compare with your prediction? Your answer: It decreased, like predicted. 3 What happened to the amount of neurotransmitter release when you switched from the extracellular fluid with no Ca 2+ to the extracellular fluid with low Ca 2+? How well did the results compare with your prediction? Your answer: It increased a small amount, like predicted. 4 How did neurotransmitter release in the Mg 2+ extracellular fluid compare to that in the control extracellular fluid? How well did the result compare with your prediction? Your answer: I was wrong and some neurotransmitter released. 5 How does Mg 2+ block the effect of extracellular calcium on neurotransmitter release? Your answer: It blocks calcium channels and inhibits the release of neurotransmitter.

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