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.