Chapter 8

Which of the following neurons or groups of neurons are NOT considered to be a part of the efferent pathway?

sensory

The part of the neuron that receives most of the incoming signals is the ________.

dendrite

What would happen to the membrane potential if a cell suddenly becomes more permeable to Na+?

Depolarize

What happens if a graded stimulus is of sufficient strength to reach threshold at the trigger zone?

An action potential occurs.

Which two properties determine the conduction velocity in a mammalian neuron?

Axon diameter and the leak resistance of the membrane

Which type of receptor would bind acetylcholine and be found in skeletal muscle?

Nicotinic cholinergic

A stronger stimulus to a neuron results in ________.

larger voltage changes in graded potentials and greater frequency of action potentials produced in response

Which of the following would NOT cause the membrane potential to change from -70 mV to +30 mV?

Potassium ions leaving the cell.

Detailed understanding of the cellular basis of signaling in the nervous system has led to good understanding of consciousness, intelligence, and emotion.

False

The brain and spinal cord together compose the

central nervous system.

Exocrine glands, smooth muscles, and cardiac muscles are controlled by the

autonomic nervous system.

Autonomic motor neurons are subdivided into the

sympathetic and parasympathetic divisions.

The enteric nervous system is a network of neurons that function in controlling

digestion.

The portions of a neuron that extend off of the roughly spherical cell body are usually collectively called

processes.

Neurotransmitter is stored and released from

axon terminals and axon varicosities.

Information coming into the central nervous system is transmitted along ________ neurons.

afferent and sensory

The afferent and efferent axons together form the

peripheral nervous system.

In general, the nervous system is composed of which two types of cells?
1. motor
2. neurons
3. sensory
4. glial
5. associative

2 and 4 neurons and glial

The cell body of neurons is generally

10% of the cell volume.

Interneurons are found

only in the CNS.

The multiple thin, branched structures on a neuron whose main function is to receive incoming signals are the

dendrites.

The collection of axons that carries information between the central nervous system and the peripheral effectors is called the

nerve

The region where the axon terminal meets its target cell is called the

synapse.

The axon is connected to the cell body by the

axon hillock.

Branches that sometimes occur along the length of an axon are called

collaterals.

Neurotransmitters are released from the

axon terminals.

The term axonal transport refers to

vesicle transport of proteins and organelles down the axon.

Anterograde and retrograde axonal transport are forms of ________ transport.

fast

Clusters of nerve cell bodies in the peripheral nervous system are called

ganglia.

Glial cells
provide structural and metabolic support and help maintain homeostasis of the brain's extracellular fluid.
only provide structural and metabolic support.
only help maintain homeostasis of the brain's extracellular fluid.
only guide neurons dur

All of the answers are correct.

Glial cells communicate primarily using

chemical signals only.

Myelin is formed by

Schwann cells and oligodendrocytes.

These glial cells act as scavengers.

microglia

During childhood, growth and development of the brain PRIMARILY occurs by increasing

neuron size and number of dendrites and synapses.

These glial cells may contribute to Lou Gehrig's disease.

microglia

Which of the following is the most common location where action potentials originate?

axon hillock

The Nernst equation predicts

the membrane potential resulting from permeability to a single ion.

Which is the correctly written Nernst equation?

61/z � log [ion]out / [ion]in

What does the Goldman-Hodgkin-Katz equation take into account that the Nernst equation does NOT?

the permeabilities of the ions

The resting membrane potential results from

uneven distribution of ions across the cell membrane and differences in membrane permeability to Na+ and K+.

Which ion(s) is/are higher in concentration inside the cell compared to outside?

potassium

The channelopathy known as QT syndrome is a result of mutation in ________ channels.

sodium, potassium, or calcium

Ion channel inactivation is

closing of the channel even when the stimulus continues.

The rising phase of the action potential is due to

Na+ flow into the cell only.

The falling phase of the action potential is due primarily to

K+ flow out of the cell only.

Choose all of the items that are incorrectly matched.
Check all that apply.
activation gate opened at rest
inactivation gate closed at rest
inactivation gate closed during repolarization
activation gate opens during depolarization

activation gate opened at rest
inactivation gate closed at rest

The point during an action potential when the inside of the cell has become more positive than the outside is known as the

overshoot.

The absolute refractory period of an action potential

ensures one-way travel down an axon, allows a neuron to ignore a second signal sent that closely follows the first, and prevents summation of action potentials.

In order to signal a stronger stimulus, action potentials become

more frequent only.

All of the following must occur before a second action potential can begin, EXCEPT

the Na+ and K+ ions that moved in/out of the cell must move back to their original compartments.

Voltage-regulated channels are located

in the membranes of dendrites, in the membranes of axons, and on the neuron cell body.

The sodium-potassium exchange pump

requires ATP to function.

The all-or-none principle states that

all stimuli great enough to bring the membrane to threshold will produce action potentials of identical magnitude.

When voltage-gated Na+ channels of a resting neuron open,

Na+ enters the neuron and the neuron depolarizes.

When voltage-gated K+ channels of a resting neuron open,

K+ leaves the neuron.

In the membrane of a resting nerve cell, when chemically gated Cl- channels open,

Cl- ions enter the cell.

Which of the following will best increase the conduction rate of action potentials?

Increase the diameter of the axon, increase the resistance of the axon membrane to ion leakage.

Action potentials are primarily associated with the membranes of

axons only.

Which of the following does NOT influence the time necessary for a nerve impulse to be conveyed by a particular neuron?

whether axon is sensory or motor

Ion concentrations are first significantly affected after ________ action potential(s).

a few thousand

The total amount of neurotransmitter released at the axon terminal is directly related to

the total number of action potentials.

Which type of synapse is most prevalent in the nervous system?

chemical

To increase the amount of neurotransmitter released onto a postsynaptic cell, the presynaptic cell would have to

send action potentials with higher frequency.

The ion necessary to initiate the release of acetylcholine into the synaptic cleft is

calcium.

The neurotransmitter thought to be involved in learning and memory is

glutamate.