Question 1

Why are mitochondria necessary at axon terminals?

Accepted Answer

The answer of Why are mitochondria necessary at axon terminals?...

Question 2

The basis of neural integration is

Accepted Answer

Neural integration refers to the process by which the nervous system combines and processes information from multiple sources, including sensory inputs and internal states. The basis of this integration is the summation of postsynaptic potentials (PSPs) that occur in overlapping time and space. PSPs can be either excitatory or inhibitory and can add together to create a net effect that determines whether a neuron will fire an action potential or not. This process is known as temporal and spatial summation. Therefore, choice A, which describes the addition of PSPs overlapping in time and space, is the best choice.

Question 3

Tom's father suffers a stroke that leaves him partially paralyzed on his right side.What type of glial cell would you expect to find in increased numbers in the damaged area of the brain that is affected by the stroke?

Accepted Answer

Microglia are the specialized immune cells of the central nervous system that respond to injury and inflammation. Following a stroke, microglia become activated and migrate to the damaged area, where they phagocytose debris and dead cells, and release pro-inflammatory cytokines. Therefore, an increase in the number of microglia would be expected in the damaged area of the brain affected by the stroke. Astrocytes play a supportive role in the brain, Schwann cells myelinate peripheral nerves, and oligodendrocytes myelinate central nerves, and none of these cells are primarily involved in the immune response to brain injury.

Question 4

Graded potentials that arrive at postsynaptic neurons are called ________ if they make that cell more likely to fire.

Accepted Answer

The answer of Graded potentials that arrive at postsynaptic neurons...

Question 5

Caffeine, nicotine, and alcohol all have effects on

Accepted Answer

Caffeine, nicotine, and alcohol all affect synaptic activity by modulating neurotransmitter release and/or receptor activity. Caffeine blocks the action of adenosine, a neurotransmitter that inhibits neuronal activity, leading to increased release of other neurotransmitters. Nicotine mimics the action of acetylcholine, a neurotransmitter that stimulates neuronal activity, leading to increased release of dopamine, serotonin, and other neurotransmitters. Alcohol enhances the activity of GABA, an inhibitory neurotransmitter, leading to decreased release of glutamate, an excitatory neurotransmitter.

Question 6

For ________ to occur, a second potential must arrive before a previous one has been completed.

Accepted Answer

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Question 7

When two or more graded potentials arrive at the trigger zone within a short period of time, their effects are additive and ________ occurs.

Accepted Answer

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Question 8

Draw a motor neuron, being sure to include and label the following parts: axon(s), dendrite(s), cell body, axon collateral(s), axon terminal(s), myelin sheath, and other components as applicable.

Accepted Answer

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Question 9

Graded potentials that increase the likelihood of an action potential bring the ________ closer to threshold.

Accepted Answer

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Question 10

Learning and memory are thought to be due to a synaptic phenomenon known as

Accepted Answer

Long-term potentiation (LTP) is a synaptic phenomenon that is believed to underlie learning and memory. LTP is a long-lasting increase in the strength of synaptic connections between neurons that occurs in response to repetitive stimulation. This strengthening of connections allows for more efficient communication between neurons and is thought to be a key mechanism underlying learning and the formation of memories.

Question 11

Arrange the following events in the proper sequence:
1)Efferent neuron reaches threshold and fires an action potential.
2)Afferent neuron reaches threshold and fires an action potential.
3)Effector organ responds by performing output.
4)Integrating center reaches decision about response.
5)Sensory organ detects change in the environment.

Accepted Answer

The sequence of events in a reflex arc is as follows: 
1) Sensory organ detects change in the environment (5) 
2) Afferent neuron reaches threshold and fires an action potential (2) 
3) Integrating center reaches decision about response (4) 
4) Efferent neuron reaches threshold and fires an action potential (1) 
5) Effector organ responds by performing output (3)

Therefore, the correct sequence is 5, 2, 4, 1, 3, which corresponds to option B.

Question 12

Tetrodotoxin is a toxin that blocks voltage-gated sodium channels.What effect does this substance have on the function of neurons?

Accepted Answer

Tetrodotoxin blocks voltage-gated sodium channels, which are responsible for the depolarization phase of action potentials in neurons. Without these channels, the neuron is unable to propagate action potentials and therefore cannot function properly. Choices A, B, and C are incorrect because they suggest an increase in neuronal activity, when in fact tetrodotoxin has the opposite effect. Choice E is also incorrect because the toxin clearly interferes with the function of voltage-gated sodium channels that are necessary for normal neuronal function.

Question 13

Briefly explain the gross organization of the nervous system in either paragraph form or using a concept map.Be sure to discuss the central, peripheral, and enteric nervous system and the divisions and branches discussed in the text.

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Question 14

A change in the conditions in the axon terminal can cause a change in the environment of the cell body as a result of ________.

Accepted Answer

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Question 15

Presynaptic facilitation occurs when

Accepted Answer

Presynaptic facilitation occurs when calcium channels in the presynaptic membrane remain open longer. This allows for an increased influx of calcium ions, which in turn increases the release of neurotransmitters into the synaptic cleft, leading to facilitation of synaptic transmission.

Question 16

Inhibition of neural activity can result from

Accepted Answer

Inhibition of neural activity can result from both presynaptic events (e.g. reduction of neurotransmitter release) and postsynaptic events (e.g. hyperpolarization of the postsynaptic neuron). Therefore, the best choice is C, which includes both presynaptic and postsynaptic events.

Question 17

Receptors that work through second messenger systems are called ________ receptors.

Accepted Answer

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Question 18

How would blocking retrograde transport in an axon affect the activity of a neuron?

Accepted Answer

Retrograde transport in an axon is responsible for carrying signals and materials from the axon terminals back to the cell body. Blocking this transport would prevent the cell body from receiving signals or materials from the distal end of the axon, affecting its ability to respond to changes or damage at the axon's distal end.

Question 19

Products from the cell body of a neuron are transported to the axon terminals by ________.

Accepted Answer

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Question 20

Graded potentials that arrive at postsynaptic neurons are called ________ if they make that cell less likely to fire.

Accepted Answer