Nervous system : Nervous Tissue
when the inactivation gate of a voltage gated sodium channel closes the activation gate is ___
open
sensory and motor nerves are part of the ___ nervous system
peripheral
the picture depicts the process of myelination in the __ nervous system
peripheral
which of the following are functions of astrocytes
regulates the composition of interstitial fluid replaces damaged neurons helps form the blood brain barrier
match the states of the sodium channel with their correct descriptions
resting - entry of sodium is prevented, activation gate is close activation- sodium moves into the cell through the open channel inactivation- entry of sodium is prevented activation gate is open
which of the following membrane transporters are present throughout the membrane of a neuron?
sodium leak channels Na+ K+ pumps potassium leak channels
t or F in saltatory conduction, Na+ only flow across the axon membrane at the neurofibril nodes
t
voltage gated calcium channels are found mostly in the ___ segment
transmissive
t or F facilitation and inhibition may be caused by changes in either the presynaptic neuron or the postsynaptic neuron
true
the voltage gated sodium channels undergo changes in activity during the depolarization phases of an action potential. place these in order from first to last
1. a graded potential depolarizes the intital segment 2. voltage gated sodium channels open 3. sodium flows into the neuron at the initial segment 4. further depolarization of the initial segment occurs 5. sodium channels enter the inactive state
place the events of synaptic transmission from earliest to latest
1. action potential reaches synaptic knob 2. voltage gated calcium channels open 3. calcium enters the synaptic knob 4. calcium triggers exocytosis of vesicles 5. neurotransmitter diffuses across synaptic cleft 6. neurotransmitter binds to postsynaptic receptors
T or F ion channels use the energy of ATP to maintain concentration gradients across neuron membranes
F
T or F ion channels use the energy to ATP to maintain concentration gradients across neuron membranes
F
which of the following ions have leak channels on the plasma membrane
Na+ K+
which of the following pumps can you find the plasma membrane
Na+/K+ Ca2+
match the time periods indicated by the arrows with their descriptions
a- absoulte refractory period b- relative refractory period ( has loop)
in which direction does fast axonal transport occur
anterograde and retrograde
which of the following statements correctly describes the role of k+ leak on the resting membrane potential
as potassium flows out of a cell the inside of the cell becomes more negative
which functional division of the nervous system controls involuntary movement of smooth muscle?
autonomic motor nervous system
the plasma membrane of an axon is called the
axolemma
the axon hilcock connects the ___ to the soma
axon
a synapse us a junction
between a neuron and another cell
synapses are classified as
chemical synapses electrical
which of the following is best described as a channel that is usually closed that open in response to binding a neurotransmitter and that when open, allow a specific type of ion to diffuse across the plasma memebrane
chemically gated channel
which of the following are among the general characteristics of graded potential
decrease intensity with distance traveled along membrane can either be depolarizing or hyperpolarizing degree of change in membrane potential is dependent of the stimulus magnitude
acetylchollnesterase removes from the synaptic cleft via
degradation
___ occurs when the inside of the cell becomes more positive than the resting membrane potential
depolarization
which of the following processes are occuring during the synaptic delay
diffusion of neurotransmitter binding of neurotransmitter to receptors release of neurotransmitter
tissue that respond to neural input by changing its activity is called
effector
the net diffusion of a given ions is dependent ipon its
electrochemical gradient
the e in EPSP stands for ___ meaning that the potential makes the inside of the postsynaptic cell more ___
excitatory positive
place the events of an EPSP in order
excitatory neurotransmitter binds to receptor Na+ channel Na+ enter the postsynaptic cell the inside of the cell becomes more positive the local current of Na+ becomes weaker as it moves toward the axon hilcock
when chemically or voltage gated channels open, there is a change in ion ___ across a membrane
flow
a cluster of neuron cell bodies found along a peripheral nerve is known as
ganglia
synapses occur where axons contat
gland cells muscle cells other neurons
match the neurotransmitter with its class
glutanate- amino acid norepinephrine- monoamine neuropeptide- sommatostatin
negatively charged proteins and other large organic molecules are found in
greater amounts inside a neuron
___ occurs when the inside of a cell becomes more negative than the resting membrane potential
hyperpolarization
the electrical gradient in a resting neuron is such that the ___ of the cell is negative relative to the ___
inside outside
PSPs are considered graded potentials because the more tranmitter is released the ___ the PSP
larger
which of the following is used for fast axonal transport
microtubules motor proteins ATP
which of the following conditions can make a PSP larger
more transmitter is releases more postsynaptic channels open
the autonomic division of the nervous system is part of the ___ nervous system
motor
interneurons facilitate communication between __ neurons and ___ neurons
motor sensory
match the structure with the appropriate letter
a- olgodenocyte b- axons c- nucleus d- mylein sheath
the components of the somatic division are
hearing joints and muscle taste
place the events of chloride based IPSP in order from earliest to latest
inhibitory neurotransmitter binds to postsynaptic chemically gated chloride channels 2. chloride moves from outside the cell to the inside 3. the inside of the postsynaptic cell becomes more negative 4. the local chloride current becomes weaker as it moves toward the axon hilock
choose which of the following can be the mechanism by which neurotoxins may do harm
interfere with transmission of action potentials induce detrimental structural change to a neuron after events that occur at a synapse
the autonomic nervous system is also known as the
involuntary nervous system
if you were moving across a neuron's membrane from the receptive segment toward the transmissive segment, where would you first encounter large numbers of voltage gates Na+ and K+ channels?
the initial segment
which of the following sgments of a neuron contains large numbers of voltage gates potassium channels and voltage gated sodium channels
the initial segment the conductive system
what must happen in order for a chemical signal to change the membrane potential of a neuron?
there must be a change in the name of open ion channels there must be a change in ion flow across the membrane
which of the following are true of neurolemmocytes?
they create the myelin sheath in the PNS they are also called Schwann cells