module 5.2

Question 1

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

Answer 1

denervation supersensitivity

Question 2

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

Answer 2

decreased activity of surviving neurons after other neurons are damaged

Question 3

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

Answer 3

Large amounts of scar tissue

Question 4

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

Answer 4

secrete chemicals that inhibit axon growth

Question 5

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

Answer 5

Giving stimulant drugs combined with physical therapy

Question 6

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

Answer 6

get the patients to make as much use as possible of the impaired systems

Question 7

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

Answer 7

those in the peripheral nervous system but not in the central nervous system

Question 8

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

Answer 8

somatosensory cortex

Question 9

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

Answer 9

the most common cause of brain damage in young adults

Question 10

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

Answer 10

breaks up blood clots

Question 11

Heightened sensitivity to a neurotransmitter after the destruction of an incoming axon is known as:

axon supersensitivity
disuse supersensitivity
enervation supersensitivity
denervation supersensitivity

Answer 11

denervation supersensitivity

Question 12

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

Answer 12

The second and fourth fingers and part of the palm

Question 13

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

Answer 13

does not use it, even though it can still control the muscles

Question 14

A continuing sensation of an amputated body part is called?

Phantom Limb
Ghost Limb
Neuralgia
Tingling Limb

Answer 14

Phantom Limb

Question 15

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

Answer 15

lose much of their oxygen and glucose supplies

Question 16

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

Answer 16

leave vacant synaptic sites at several levels of the CNS

Question 17

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

Answer 17

may die days or weeks after a stroke

Question 18

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

Answer 18

closed head injury

Question 19

A stroke kills neurons in two waves, first by_______ and second by ______.

overstimulation; understimulation
understimulation; overstimulation
collateral sprouting; denervation supersensitivity
denervation supersensitivity; collateral sprouting

Answer 19

overstimulation; understimulation

Question 20

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

Answer 20

cool the brain

Question 21

__________ cells proliferate after a stroke.

Penumbra
Microglia
Ischemia
Cancer

Answer 21

Microglia

Question 22

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

Answer 22

both collateral sprouting and denervation supersensitivity

Question 23

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

Answer 23

collateral sprouting

Question 24

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

Answer 24

An increased number in the postsynaptic cell

Question 25

A stroke caused by an artery rupturing is also known as

ischemia
hemorrhage
closed head injury
penumbra

Answer 25

hemorrhage

Question 26

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

Answer 26

Synaptic reorganization

Question 27

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

Answer 27

have the amputee learn to use an artificial limb

Question 28

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

Answer 28

Ischemia from an obstruction of an artery

Question 29

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

Answer 29

can grow back under certain circumstances

Question 30

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

Answer 30

favorable in animal trials but difficult or impractical to apply to humans

Question 31

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

Answer 31

blocking glutamate receptors

Question 32

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

Answer 32

rotational forces that push the brain against the inside of the skull

Question 33

A deafferented limb:

has lost sensory input
has lost motor control
is an amputated limb
is one which an organism uses spontaneously

Answer 33

has lost sensory input

Question 34

What does edema mean?

Lack of glucose
Ischemia from an obstruction of an artery
hemorrhage of an artery
swelling due to accumulation of fluid

Answer 34

swelling due to accumulation of fluid