Chapter 12 - Nervous System: Nervous Tissue
Ganglia are clusters of nerve cell bodies located within the CNS
False, ganglia are in the PNS
What nerves always relay information to the CNS?
Sensory nerves
What channel is needed for the generation of an action potential? a. voltage gated channels b. chloride leak channels c. chemically gated channels
a
Which of the following ions have leak channels on the plasma membrane? a. Na+ b. Ca2+ c. H+ d. K+
a & d
The _____________ refractory period is when a membrane cannot respond to another stimulus, no matter how strong.
absolute
Pain receptors in the skin send signals to the CNS for processing. These pain receptors are an example of afferent/efferent neurons.
afferent
The refractory period occurs immediately _________ an action potential.
after
When threshold is reached, depolarization occurs with the same amplitude of potential change. This is known as the
all-or-none principle
________ channels allow ungated flow of specific ions from regions of high concentration to regions of low concentration.
leak
Which terms are used for structural classification of nerves?
spinal and cranial
Neurotransmitters are removed from a synapse from degradation and reuptake
true
On a graph of an action potential, the small depolarizations that lead to threshold are from
EPSPs
To enhance the effect acetylcholine has in a particular synapse, a drug may block acetylcholinesterase (AChE) so that
acetylcholine is not destroyed and will remain in the synapse longer
What cells are star shaped?
astrocytes
Which glial cell is star shaped and help forms the blood-brain barrier?
astrocytes
The _________ division of the NS is subdivided into the sympathetic and parasympathetic divisions.
autonomic
Which of the following pumps ca be found in the plasma membrane? a. H+ b. Ca2+ c. Na+/K+ d. CI-
b & c
Acetylcholinesterase
catalyzes hydrolysis of ACh to remove it from the synaptic cleft.
Satellite cells are found surrounding
cell bodies
Ependymal cells help produce
cerebrospinal fluid
When a neurotransmitter binds a protein channel, it opens and lets sodium diffuse down its concentration gradient. This is an example of a
chemically-gated sodium channel
The somatic sensory division detects stimuli that are ________ detected.
consciously
Upon binding of endocannabinoids to their target, there is a(n)
decrease in neurotransmitter release from presynaptic neurons
The tissues that receive nerve impulses from motor neurons are called
effectors
The motor nervous system is also referred to as the ________ division.
efferent
Neurons that carry signals from the CNS to skeletal muscle for contraction would be classified as _____________ neurons.
efferent from motor NS
Synapses are classified as
electrical or chemical synapses
EPSPs and IPSPs have long term effects on a neuron
false
Glial cells help neurons by generating action potentials.
false, glial cells don't generate action potentials
In neurons, protein pumps allow substances to move passively down their concentration gradients.
false, pumps are not involved in passive transport
An axon with a large diameter transmits an impulse ___________ than an axon with a smaller diameter
faster
A(n) ___________ results in a swelling, enlarged portion, along the length of a nerve, which is often large enough to be visible by the naked eye.
ganglion
Negatively charged proteins and other large organic molecules are found in
greater amounts inside the neuron
____________________ occurs when the inside of a cell becomes more negative than the resting membrane potential
hyperpolarization
Neuronal pools are composed of
interneurons
What cells wander through the CNS and replicate in response to infection?
microglia
Which glial cell acts as a phagocyte?
microglial cells
The vagus nerve contains afferent and efferent neurons; therefore it is an example of a(n) ___________ nerve
mixed
What would increase the magnitude of a postsynaptic potential?
more neurotransmitter released from presynaptic neuron, more chemically gated channels open in postsynaptic neuron
Nerve growth factors that stimulate outgrowth of severed axons are secreted by
neurolemmocytes
Nervous tissue is composed of glial cells and
neurons
Bipolar neurons have how many axons and dendrites?
one of each
When sodium chemically enters the neuron, the membrane will depolarize thus becoming more ____________ in charge
positive
The ________ NS transmits information from receptors to the CNS, while the __________ NS transmits information from the CNS to the rest of the body
sensory, motor
As a result of a neurotransmitter opening up chemically gated sodium channels on the postsynaptic membrane,
sodium ions enter the cell
Receptors detect change from the external or internal environment. These changes are called
stimuli
A change in membrane potential insufficient to cause an action potential is called a
subthreshold potential
The process by which postsynaptic potentials are added together at the initial segment is known as
summation
A typical synapse in the CNS consists of a presynaptic neuron and a postsynaptic neuron, separated by a narrow space called the
synaptic cleft
Which part of a neuron contains calcium pumps and channels?
synaptic knobs/bulbs
Fifty presynaptic neurons all briefly release a single burst of excitatory neurotransmitter, generating excitatory postsynaptic potentials (EPSPs) in a postsynaptic neuron. Using this example, select all that apply.
the EPSPs will be summed at the axon hillock
Which of the following characteristics of action potentials can vary?
the frequency of action potentials
The negative value of the RMP means that
the inside of the cell is more negative compared to the outside of the cell
Scorpion agitoxin is a neurotoxin that blocks the activity of voltage-gated potassium channels. In the presence of agitoxin, which will occur during an action potential?
the neuron will remain depolarized and unable to repolarize
An EPSP causes
the postsynaptic neuron's membrane potential to become more positive
A regenerating axon in the PNS is guided by the regeneration tube and grows at a rate of about 5mm per day
true
If extracellular concentrations of potassium are increased dramatically, a neuron may not be able to repolarize during an action potential
true
On a typical neuron, the axon is longer in length than the dendrites
true
The entry of sodium ions into the postsynaptic neuron causes depolarization
true
The enzyme acetylcholinesterase causes acetylcholine to break down into acetate and choline, stopping the stimulation of a postsynaptic cell
true
Postsynaptic neurons can generate both inhibitory and excitatory postsynaptic potentials simultaneously.
true?
Sensory information from the visceral sensory division is _____________ sensed
unconsciously
Most afferent neurons are classified functionally as
unipolar