human anatomy chapter 12
______ is a typical resting membrane potential for a neuron. -30 millivolts -70 millivolts -100 millivolts +70 millivolts
-70 millivolts
There are ______ different types of glial cells in the CNS. 2 3 4
4
______ is responsiveness to a stimuli. Secretion Excitability Amiotic Conductivity
Excitability
Propagation of depolarization only flows away from the cell body towards the synaptic knob because ______. previous regions in the axon have only potassium channels previous regions in the axon have sodium channels in the inactive state previous regions of the axon are already repolarized
previous regions in the axon have sodium channels in the inactive state
Membrane molecules that use the energy of ATP to move ions against a concentration gradient are called ______
pumps
An axon is either incapable of generating an action potential or requires a larger than normal stimulus during the _______ period.
refractory
Dendrites are ______ than axons. shorter longer
shorter
The all-or-none law refers to the fact that action potentials will only occur if the initial segment reaches ______
threshold
The conductive segment of a neuron is/are the ______. axon hillock terminal branches total length of the axon
total length of the axon
In retrograde transport, substances are moved ______ the cell body. away from toward
toward
True or false: Voltage-gated sodium ion channels are closed initially and the membrane potential is -70 mv.
true
Most afferent neurons are classified functionally as ______. bipolar multipolar unipolar
unipolar
Initially, the voltage-gated Na+ channels are closed and the membrane potential is ______ mV. As Na+ flows in the membrane potential changes to ______ mV and the threshold is reached. -70; -90 -70; -55 -55; -70 -90; -70
-70; -55
If only K+ leak channels were present, the membrane potential would be ______. -75 mV -55 mV 0 mV -90 mV
-90 mV
______ is a type of membrane transport protein that increases the potential energy across a membrane. A ligand gated ion channel A leak channel A voltage gated ion channel A pump
A pump
Numerous ______ must be generated and arrive at the initial segment at nearly the same moment if a threshold is to be reached. IPSPs EPSPs
EPSPs
______ is what underlies the absolute refractory period. Inactivation of sodium channels Activation of potassium channel Inactivation of potassium channels Activation of sodium channels
Inactivation of sodium channels
Repolarization is due to the opening of voltage-gated _______ and the subsequent movement of _____ out of the cell. K+/Na+ Na+/Na+ Na+/K+ K+/K+
K+/K+
______ represents the smallest percentage of CNS glial cells. Oligodendrocytes Ependymal cells Astrocytes Microglia
Microglia
The threshold is reached when the ______ ions flow into the cell. Na+ K+ Ca++ Cl-
Na+
Which of the following pumps can you find in the plasma membrane? Multiple select question. Na+/K+ H+ Ca2+ Cl-
Na+/K+ Ca2+
Which of the following membrane transporters are present throughout the membrane of a neuron? voltage-gated sodium channels voltage-gated potassium channels Na+/K+ pumps potassium leak channels sodium leak channels
Na+/K+ pumps potassium leak channels sodium leak channels
The nerve impulse has the voltage-gated ______ channels opened first followed by the opening of the voltage-gated ______ channels. K+; Na+ K+; Cl- Na+; Cl- Na+; K+
Na+; K+
Action potentials are always propagated along an axon at the same ______ but ______ can vary depending on the strength of the stimulus. frequency; amplitude amplitude; frequency
amplitude; frequency
An epineurium surrounds ______. a nerve fascicle an individual axon an entire nerve
an entire nerve
The nerve impulse causes ______ in the number of calcium ions that enter the synaptic knob an increase a decrease
an increase
The endoneurium surrounds ______. an individual axon a nerve fascicle the entire nerve
an individual axon
The voltage-gated potassium channels ______ during repolarization. are in resting state are closed are inactivated are open
are inactivated
The voltage-gated potassium channels ______ during repolarization. are open are in resting state are closed are inactivated
are open
The perivascular feet of the ______ help create a blood-brain barrier. oligodenrocyte ependymal cell astrocyte microglial cell satellite cell
astrocyte
Which glial cell occupies the space of dying neurons? astrocytes microglia ependymal cells oligodendroctyes
astrocytes
The synaptic knob is found ______. at the extreme tips of the axon between the cell body and dendrite in the nucleus between the axon and axon hillock
at the extreme tips of the axon
The division of the nervous system that is subdivided into the sympathetic and parasympathetic divisions is the ______ nervous system.
autonomic
The ______ is sometimes called the nerve fiber. soma axon nucleus dendrite
axon
A fascicle is a bundle of ______. axons capillaries veins
axons
The presence of ______ ions causes the synaptic vesicles to bind to the membrane, allowing neurotransmitters to be released. sodium chloride potassium calcium
calcium
The ependymal cells help produce ______. urine white blood cells blood plasma cerebrospinal fluid
cerebrospinal fluid
Most synapses in the human body are ______ synapses. chemical electrical
chemical
Synapses are classified as ______. mechanical synapses chemical synapses electrical synapses
chemical synapses electrical synapses
Ependymal cells produce and circulate cerebrospinal fluid. The ______ helps circulate the CSF. cilia microtubule centriole flagella
cilia
Ganglia are ______. bundles of axons clusters of neuron cell bodies
clusters of neuron cell bodies
Match the neuronal structure with the appropriate description. dendrites axon hillock axon axoplasm
conduct information to to cell body triangular region connecting the axon to the cell body conducts information away from the cell body the cytoplasm of the axon
The total length of the axon is called the ______ segment.
conductive
A positive change in the membrane potential is called ______. inactivation repolarization hyperpolarization depolarization
depolarization
The event that occurs when the inside of the cell becomes more positive (less negative) than the resting membrane potential is called ______
depolarization
Membrane channels provide the means to move a substance ______ its concentration gradient. down up
down
Creating and transmitting ______ currents is central to the function of neuron physiology.
electrical
A difference in the number of charged particles between two sides of the membrane forms a(n) ______. chemical gradient sodium gradient electrical gradient
electrical gradient
Place the events of an EPSP in order
excitatory neurotransmitter binds to receptor Na+ channel more Na+ enter the postsynaptic cell then K+ leaves the inside of the cell becomes more positive the local current of Na+ becomes weaker as it moves toward the axon hilcock
True or false: A neuromodulator is another name for a neurotransmitter.
false
True or false: The relative charge across a neuron's plasma membrane is negative outside the cell relative to the inside of the cell.
false
Sensory input and motor output are used to divide the nervous system ______. functionally structurally
functionally
Neuron cell bodies in the peripheral nervous system are found clustered in ______. nuclei glomeruli ganglia
ganglia
The peripheral nervous system is made of nerves and _______
ganglia
A cluster of neuron cell bodies found along a peripheral nerve is known as a(n) _______
ganglion
A potential that is a temporary change in membrane potential which lasts only as long as the stimulus that causes it and can vary in size is called a ______ potential.
graded
Negatively charged proteins and other large organic molecules are found in ______. equal amounts inside and outside a neuron greater amounts inside a neuron greater amounts outside a neuron
greater amounts inside a neuron
The changes in membrane potential associated with both EPSP and IPSP inputs are "added" in the ______ to determine if an action potential is initiated and the threshold is reached. postsynaptic membrane axon conductive segment initial segment
initial segment
The electrical gradient in a resting neuron is such that the _____ of the cell is negative relative to the _______
inside outside
Which of the following are functional classes of neurons? interneurons bipolar neurons multipolar neurons unipolar neurons motor neurons sensory neurons
interneurons motor neurons sensory neurons
Match the location with the larger concentration of ions. organic ions sodium
intracellular extracellular
The autonomic nervous system is ______. voluntary involuntary
involuntary
During an action potential, voltage-gated potassium channels open after voltage-gated sodium channels. The effect this has on the membrane potential is ______. it has no effect on the membrane potential it becomes more positive it becomes less positive and more negative
it becomes less positive and more negative
Channels that allow an ungated flow of specific ions from regions of high concentration to regions of low concentration are called ________ channels.
leak
Which glial cells remove debris from damaged or dead nervous tissue? oligodendrocytes microglia schwann cells ependymal cells
microglia
Cells that wander through the CNS and replicate in response to infection are called ______
microglial
The brain interprets the increased frequency of nerve signals as a ______ stimulus. more intense less intense
more intense
Interneurons are ______ neurons. unipolar bipolar multipolar
multipolar
Most motor neurons are ______. multipolar unipolar bipolar
multipolar
______ neurons are most common. Unipolar Multipolar Bipolar
multipolar
Oligodendrocytes create the _______ sheath in the central nervous system.
myelin
The presence of a ____ sheath increases the rate of impulse conduction.
myelin
What is found in the ganglia of spinal nerves? neuron cell bodies motor nerves only entire axons
neuron cell bodies
Neuromodulation alters the response of ______ to neurotransmitters. glial cells neurons
neurons
The components of nervous tissue that conduct electrical impulses are ______. blood vessels glial cells neurons ganglia
neurons
Chemicals that are released from synaptic knobs and bind to receptors on postsynaptic membranes are called ______
neurotransmitters
The neuron cell body houses both the ______ and the cytoplasm. myelin sheath nucleus dendrite axon axon hillock
nucleus
Which of the following would be likely to cause hyperpolarization of a neuron? opening of a chemically gated chloride channel opening of a voltage-gated potassium channel opening of a chemically gated sodium channel opening of a voltage-gated sodium channel
opening of a chemically gated chloride channel opening of a voltage-gated potassium channel
Which of the following would be likely to cause depolarization of a neuron? opening of a voltage-gated sodium channel opening of a chemically gated sodium channel opening of a chemically gated chloride channel opening of a voltage-gated potassium channel
opening of a voltage-gated sodium channel opening of a chemically gated sodium channel
A fascicle is surrounded by a layer of dense irregular connective tissue called ______. epineurium fascia endoneurium perineurium
perineurium
Spinal nerves are part of the ______ nervous system. peripheral central
peripheral
The sequential opening of voltage-gated sodium channels is followed by the sequential opening of voltage-gated ______ channels.
potassium
A return of the membrane potential towards the resting membrane potential immediately the following depolarization is called ______. depolarization repolarization summation
repolarization
Na+ and K+ leak channels and Na+/K+ pumps on the neuron are responsible for establishing and maintaining the _______ membrane ______
resting potential
The relative difference in charge across the plasma membrane of a resting neuron is known as the _______ ________ ________
resting membrane potential
The function of a neuron is dependent on ______. resting membrane potentials changing resting membrane potentials staying the same
resting membrane potentials changing
The removal of neurotransmitters from the synaptic cleft by transport into the synaptic knob is known as ______. degradation reuptake diffusion
reuptake
Chromatophilic substance and Nissl bodies are both types of _____-.
ribosomes
Which of the following are characteristics of neurons? secretion conductivity amitotic excitability nonexcitable extreme longevity protection support
secretion conductivity amitotic excitability extreme longevity
Glial cells are ______ than neurons. larger smaller
smaller
The flow of ______ ion is the most common cause of depolarization. sodium calcium potassium chloride
sodium
The flow of ______ ion is the most common cause of depolarization. sodium potassium calcium chloride
sodium
An action potential cannot be initiated during the absolute refractory period because ______. sodium channels are inactivated, and thus can not open potassium channels are inactivated, and thus can not open there are no sodium channels in the membrane potassium channels are activated
sodium channels are inactivated, and thus can not open
A damaged axon within the PNS can regenerate if ______. some neurilemma remains part of the cell body remains some oligodendrocytes remain some dendrocytes remain
some neurilemma remains
Fill in the blank question. The process by which postsynaptic potentials are added together at the initial segment is known as ______
summation
Neurons integrate multiple synaptic inputs by the process of ______. conduction propagation anterograde transport summation
summation
Neurotransmitters are stored in ______. motor end plates axon hillocks synaptic vesicles
synaptic vesicles
"An action potential either happens or it doesn't." This statement could also be called ______. the all-or-none law the refractory law the threshold law
the all-or-none law
The two factors that affect PNS regeneration are ______. the amount of damage presence of ependymal cells rate of microglial cell division the distance between the injury site and the effector organ
the amount of damage the distance between the injury site and the effector organ
The myelin sheath covers ______. the axon the cell body the nerve the choroid plexus
the axon
If summated PSPs reach a threshold, an action potential begins first in ______. the dendrites the initial segment the axon the cell body
the initial segment
The voltage-gated sodium channels undergo changes in activity during the depolarization phase of an action potential. Place these in order from first to last.
the membrane potential is -70 mv sodium ions flow into the neuron the membrane potential becomes more positive voltage gated sodium ion channels open
Vesicles involved in retrograde transport are moving ______ the cell body. toward away from toward and away from
toward
The blood-brain barrier helps protect the brain from ______. blood electricity toxins water
toxins
True or false: Graded potentials vary in size depending on the stimulus. True False
true
True or false: In most cases, a single EPSP is not sufficient to cause a neuron to reach the threshold potential.
true
Which of the following ions have leak channels on the plasma membrane? Ca2+ H+ Na+ K+
Na+ K+
Pseudounipolar is another name for a ______ neuron unipolar bipolar multipolar
unipolar
What are the two structural examples of sensory neurons? unipolar bipolar multipolar
unipolar bipolar
______ are released from neurons in response to conductive activity. Mitotic cells Neurotransmitters Graded potentials Electrons
Neurotransmitters
________ are large cells that ensheath many different axons.
Oligodendrocytes
______ is the return of polarity from positive back to negative (the RMP). Depolarization Summation Repolarization
Repolarization
______ (is) are the slightly expanded region at the tip of the fine terminal extensions of a neuron. Axon collaterals Perikaryon Synaptic knobs
Synaptic knobs
Which describes the propagation of depolarization down an axon? Sodium influx triggers sodium efflux. The flow of Na+ to downstream regions causes depolarization of adjacent regions. Sodium flows into the cell in one region and backs out again at another region. The flow of Na+ into adjacent regions causes potassium channels to open.
The flow of Na+ to downstream regions causes depolarization of adjacent regions.
______ neurons have a single, short neuron process that emerges from the cell body and branches like a T. Unipolar Bipolar Multipolar
Unipolar
______ to help return the membrane potential to the resting state following hyperpolarization. Voltage-gated potassium channels close Na+/K+ pumps restore gradients Calcium channels open Voltage-gated sodium channels open
Voltage-gated potassium channels close Na+/K+ pumps restore gradients
______ and are the cause of hyperpolarization in an action potential. Voltage-gated potassium channels inactivate Voltage-gated chloride channels open Voltage-gated potassium channels remain open
Voltage-gated potassium channels remain open
______ there would be no net movement of K+ ions through an open K+ leak channel. When the chemical gradient is greater than the electrical gradient When the electrical gradient is greater than the chemical gradient When the electrical gradient and chemical gradient balance each other
When the electrical gradient and chemical gradient balance each other
Membrane pumps require ______ energy. no a lot of
a lot of
Sensory ______ neurons carry information ______ the central nervous system. afferent; toward efferent; away from afferent; away from efferent; toward
afferent; toward
The refractory period occurs immediately ______ an action potential. before after
after
The relative refractory period occurs ______ the absolute refractory period. after before
after
Match the neurotransmitter to its class. glutamate norepinephrine
amino acid monoamine
Match the neurotransmitter with its correct class. glycine dopamine neuropeptide
amino acid monoamine enkephalin
The ______ is the functional division of the nervous system that controls the involuntary movement of smooth muscle. visceral sensory nervous system central nervous system peripheral nervous system somatic motor nervous system somatic sensory nervous system autonomic motor nervous system
autonomic motor nervous system
The plasma membrane of an axon is called the _______
axolemma
Cytoplasm within an axon is called ______. axoplasm axolemma Nissl substance
axoplasm
Many excitatory neurotransmitters cause the opening of channels that allow for the flow of ______. Cl- only Na+ only both Na+ and K+ K+ only
both Na+ and K+
Which are components of the central nervous system? brain and spinal cord cranial nerves and the brain cranial and spinal nerves
brain and spinal cord
Dendrites branch off of the ______. synaptic knobs cell body axon axon hillock
cell body
Soma is another name for the ______. dendrites axon hillock cell body myelin sheath axon
cell body
The brain and spinal cord are part of the ______. peripheral nervous system motor nervous system central nervous system sensory nervous system
central nervous system
Another way for the neurotransmitter to be removed from the synaptic cleft is by ______ where there is uptake by surrounding glial cells. extrusion reuptake diffusion
diffusion
Glial cells ______ transmit electrical impulses. do not do
do not
The tissues that receive nerve impulses from motor neurons are called ______. receptors effectors
effectors
Motor neurons are classified as ______ neurons. interneuron afferent efferent
efferent
Synaptic knobs are also called ______. somas nerve fibers end bulbs terminal boutons
end bulbs terminal boutons
An individual axon is wrapped in a connective tissue covering called the ______. epineurium endoneurium perineurium
endoneurium
The choroid plexus is made from capillaries and ______. astrocytes microglial cells oligodendrocytes ependymal cells
ependymal cells
The lining ventricles of the brain is a location of ______. Multiple choice question. microglia satellite cells astrocytes ependymal cells
ependymal cells
Choose the cells that are part of the central nervous system. neurolemmocyte ependymal cells astrocyte oligodendrocyte satellite cells microglia
ependymal cells astrocyte oligodendrocyte microglia
An entire nerve is surrounded by a connective tissue covering called the ______. epineurium endoneurium perineurium
epineurium
A larger axon transmits an impulse ______ than a smaller axon. slower faster
faster
Neurons are classified ______ depending on the direction the nerve impulse travels. structurally functionally
functionally
The chromatophilic substance helps create the ______ color in parts of the brain and spinal cord. white gray
gray
The functions of astrocytes are to ______. help form the blood-brain barrier myelinate axons of the PNS regulate the composition of interstitial fluid produce cerebrospinal fluid assist neuronal development
help form the blood-brain barrier regulate the composition of interstitial fluid assist neuronal development
Fill in the blank question. Immediately following the repolarization of an action potential, the membrane undergoes _______ before returning to the resting membrane potential.
hyperpolarization
The event that occurs when the inside of a cell becomes more negative than the resting membrane potential is called ________
hyperpolarization
The myelin sheath is made of a high percentage of ______. lipids carbohydrates nucleic acids
lipids
It usually takes ______ neurolemmocytes to myelinate one axon. many two one
many
The resting membrane potential is measured in ______. millifarads milliwatts millivolts milliamps
millivolts
A nerve is part of the ______ nervous system. central peripheral
peripheral
Clusters of neuron cell bodies called ganglia are found in the ______ nervous system. central peripheral
peripheral
A cablelike bundle of axons in the peripheral nervous system is called a ______. nerve ganglion tract
nerve
A ______ is the propagation of an action potential along an axon. graded potential depolarized neuron nerve impulse repolarized neuron
nerve impulse
What is the primary tissue of the nervous system? muscle tissue nervous tissue connective tissue epithelial tissue
nervous tissue
The thin outer layer of the neurolemmocyte is called the ______. cilia choroid plexus neurofibril node neurilemma
neurilemma
The ability to alter the response of neurons to neurotransmitters is known as _______.
neuromodulation