module 5.2 Flashcards
Certain axons innervating a given neuron are damaged. What compensatory change is likely to take place in that postsynaptic cell?
collateral sprouting
removal of toxins
denervation supersensitivity
decrease in glucose utilization
denervation supersensitivity
Diaschisis refers to the:
increase in activity of neurons surrounding a damaged area
decreased activity of surviving neurons after other neurons are damaged
increased activity in the cerebral cortex after damage to any part of the brain
increased activity in the hypothalamus after damage to any part of the brain
decreased activity of surviving neurons after other neurons are damaged
What is one impediment to regeneration of axons in the mammalian central nervous system?
Inhibitory chemical secreted by the damaged portion of the axon
Bacterial infections caused by the decaying tissue
Large amounts of scar tissue
Inhibitory messages sent from the cell nucleus when an axon is damaged
Large amounts of scar tissue
Scar tissue and myelin are similar in that they both
secrete chemicals to restore axons
are produced after brain damage
are formed in normal development of the nervous system
secrete chemicals that inhibit axon growth
secrete chemicals that inhibit axon growth
Which of the following treatments would be most likely to help a patient starting several days after a stroke?
Injecting a drug to block dopamine
Administering tranquilizers
Extensive bed rest
Giving stimulant drugs combined with physical therapy
Giving stimulant drugs combined with physical therapy
In dealing with brain-damaged patients, the usual goal is to:
get the patient to rely on other people for the skills that they have lost.
get the patients to make as much use as possible of the impaired systems
promote physical changes in the brain, such as collateral sprouting
encourage complete inactivity to enable the brain to engage in restorative processes
get the patients to make as much use as possible of the impaired systems
Which axons will regenerate to a significant degree if cut or crushed?
Those in invertebrates but not in a vertebrates
Only those which are unmyelinated
Those in the central nervous system but no tin the peripheral nervous system
those in the peripheral nervous system but not in the central nervous system
those in the peripheral nervous system but not in the central nervous system
Modern methods have demonstrated that phantom limbs develop only if the relevant portion of the ________ reorganizes and becomes responsive to alternative inputs.
somatosensory cortex
torso
axon
glia
somatosensory cortex
Closed head injury is:
the most common cause of brain damage in young adults
usually fatal
the most common cause of Korsakoff’s syndrome
related to Alzheimer’s disease
the most common cause of brain damage in young adults
Damage due to stroke caused by ischemia can be minimized by administering a drug that
breaks up blood clots
overstimulates neurons in and around the damaged area
increases the release of glutamate
slows down the sodium-potassium pump
breaks up blood clots
Heightened sensitivity to a neurotransmitter after the destruction of an incoming axon is known as:
axon supersensitivity
disuse supersensitivity
enervation supersensitivity
denervation supersensitivity
denervation supersensitivity
A section of the somatosensory cortex ordinarily responds to the third finger of the left hand. If that finger is amputated, to what will the cells in this part of the cortex respond.
Nothing
The second and fourth fingers and part of the palm
The third finger of the right hand
The entire left hand and the entire right hand
The second and fourth fingers and part of the palm
A monkey with one deafferented limb:
cannot control the muscles of that limb
moves that limb whenever it uses its contralateral limb
uses its spontaneously, even though the animal has lost sensation to that body part
does not use it, even though it can still control the muscles
does not use it, even though it can still control the muscles
A continuing sensation of an amputated body part is called?
Phantom Limb
Ghost Limb
Neuralgia
Tingling Limb
Phantom Limb
After ischemia, neurons deprived of blood:
transform from neurons into glia
lose much of their oxygen and glucose supplies
break down the blood-brain barrier
increase the velocity of their action potentials
lose much of their oxygen and glucose supplies
After loss of sensory input from a limb, the axons representing that limb degenerate and:
cause immediate cell death
leave vacant synaptic sites at several levels of the CNS
destroy any left over synapses
cause no change in the associated neurons
leave vacant synaptic sites at several levels of the CNS
After a stroke, cells in the penumbra:
are the first to die
help to remove dead of dying cells in the area of damage
quickly become more active, compensating for the area of damage
may die days or weeks after a stroke
may die days or weeks after a stroke
A sharp blow to the head resulting from an assault or trauma that does not actually puncture the brain is called a
stroke
cerebrovascular accident
hemmorrhage
closed head injury
closed head injury
A stroke kills neurons in two waves, first by_______ and second by ______.
overstimulation; understimulation
understimulation; overstimulation
collateral sprouting; denervation supersensitivity
denervation supersensitivity; collateral sprouting
overstimulation; understimulation
To date, the most effective laboratory method minimizing the damage resulting from stroke in nonhuman animals has been to:
use drugs which trap free radicals
use drugs which effect canabinoids
use neurotrophins which block apoptosis
cool the brain
cool the brain
__________ cells proliferate after a stroke.
Penumbra
Microglia
Ischemia
Cancer
Microglia
Damage to some of the axons that innervate a given structure may give rise to:
collateral sprouting, but not denervation supersensitivity
denervation supersensitivity, but not collateral sprouting
both collateral sprouting and denervation supersensitivity
neither collateral sprouting nor denervation supersensitivity
both collateral sprouting and denervation supersensitivity
If some of the axons innervating a given cell are destroyed or if they become inactive, what compensatory process takes place in the remaining presynaptic cells?
activation of previously silent synapses
removal of toxins
denervation supersensitivity
collateral sprouting
collateral sprouting
If supersensitivity takes place, what can one expect to find regarding the number of receptors?
an increased number in the presynaptic cell
A decreased number in the presynaptic cell
An increased number in the postsynaptic cell
A decreased number in the postsynaptic cell
An increased number in the postsynaptic cell
A stroke caused by an artery rupturing is also known as
ischemia
hemorrhage
closed head injury
penumbra
hemorrhage
A cortical cell originally responded to the stimulation of the middle finger. After amputation of that finger it begins responding to the second and fourth fingers. What most likely accounts for this?
Synaptic reorganization
Growth of completely new axons
Altered pattern of blood vessels in the brain
A psychotic reaction
Synaptic reorganization
One way to relieve the pain associated with a phantom limb is to:
remove more of the amputated limb
have the amputee learn to use an artificial limb
stimulate part of the cortex
help them understand that there is no neural basis for those sensations
have the amputee learn to use an artificial limb
Which of the following is the most common cause of a stroke
lack of glucose
Ischemia from an obstruction of an artery
Hemorrhage of an artery
Blow to the head
Ischemia from an obstruction of an artery
A damaged axon:
will never grow back
can grow back under certain circumstances
will grow back if its dendrites do also
will only grow back only if its myelinated
can grow back under certain circumstances
Researchers have tried using drugs that block apoptosis. Results have been:
favorable in animals and human trials
favorable in animal trials but too costly to try with humans
favorable in animal trials but difficult or impractical to apply to humans
unfavorable in all research trials
favorable in animal trials but difficult or impractical to apply to humans
Although the following methods may or may not actually work, which one would theoretically be of potential benefit to stroke victims?
increasing activity at glutamate receptors
opening sodium channels
closing potassium channels
blocking glutamate receptors
blocking glutamate receptors
Closed head injury results in damage partially because of:
increased production of myelin
excessive deficit of neurotrophins
rotational forces that push the brain against the inside of the skull
infection
rotational forces that push the brain against the inside of the skull
A deafferented limb:
has lost sensory input
has lost motor control
is an amputated limb
is one which an organism uses spontaneously
has lost sensory input
What does edema mean?
Lack of glucose
Ischemia from an obstruction of an artery
hemorrhage of an artery
swelling due to accumulation of fluid
swelling due to accumulation of fluid
