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AP II Exam 1 > Chapter 12 Review Questions > Flashcards

Chapter 12 Review Questions Flashcards

1
Q

Identify the 2 anatomical divisions of the nervous system

A

CNS - brain and spinal cord
PNS - all neural tissue outside of the CNS

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2
Q

Identify the 2 functional divisions of the PNS and cite their primary functions

A

afferent and efferent division

afferent – brings sensory info to the CNS from receptors in peripheral tissues and organs

efferent – carries motor commands from the CNS to muscles, glands, and adipose tissue

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3
Q

Identify the 2 components of the efferent division of the PNS

A

SNS (somatic nervous system)
ANS (autonomic nervous system)

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4
Q

What would be the effect of damage to the afferent division of the PNS?

A

The afferent division is composed of nerves that carry sensory information to the brain and spinal cord. This would interfere with a person’s ability to recognize a variety of sensory stimuli

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5
Q

Name the structural components of a typical neuron

A

cell body or soma — contains a nucleus and perikaryon (cytoplasm surrounding the nucleus)

dendrites
axon
telodendria (branched extensions off of the axon)
Nissl bodies (consist of granular ER and ribosomes)
neurofiliaments
intermediate neurotubules
neurofibrils
axolemma(portion of the plasma membrane that surrounds the axoplasm)
axoplasm (cytoplasm of the axon)
initial segment (joins with axon hillock)
axon hillock (thickened region of cell body where it joins to the initial segment)
collaterals (places where an axon branches along its length)

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6
Q

Classify neurons according to their structure

A

anaxonic (more than 2 processes, but axons cannot be distinguished from dendrites)
unipolar (a single elongate process with the cell body off to the side)
bipolar (two processes separated by the cell body)
multipolar (more than 2 processes. a single axon and multiple dendrites)

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7
Q

Classify neurons according to their function

A

Sensory neurons
Interneurons
Motor neurons

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8
Q

Are unipolar neurons in a tissue sample more likely to function as sensory neurons or motor neurons?

A

Because most sensory neurons of the PNS are unipolar, these neurons most likely function as sensory neurons

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9
Q

Identify the neuroglia of the CNS

A

oligodendrocytes
microglia
astrocytes
ependymal cells

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10
Q

Identify the neuroglia of the PNS

A

Schwaan cells (neurilemma cells)
satellite cells (amphicytes)

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11
Q

Which type of neuroglia would increase in number in the brain tissue of a person with a CNS infection

A

The small phagocytic cells called microglia occur in increased numbers in infected (and damaged) areas of the CNS

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12
Q

Define the resting potential

A

The resting potential is the transmembrane potential of a normal cell under homeostatic conditions

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13
Q

what effect would a chemical that blocks the voltage-gated sodium channels in neuron plasma membranes have on a neuron’s ability to depolarize?

A

If the sodium channels could not open, sodium ions could not flood into the cell, and it would not be able to depolarize

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14
Q

what effect would decreasing the concentration of extracellular potassium ions have on the transmembrane potential of a neuron?

A

If the extracellular concentration of potassium ions decreased, more potassium would leave the cell, and the electrical gradient across the membrane (transmembrane potential) would increase. This condition is called hyperpolarization

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15
Q

Define action potential

A

An action potential is a propagated change in the transmembrane potential of excitable cells, initiated by a change in the membrane permeability to sodium ions

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16
Q

List the steps involved in the generation and propagation of an action potential

A
  1. Depolarization of threshold
  2. Activation of sodium channels and rapid depolarization
  3. Inactivation of sodium channels and activation of potassium channels
  4. Return to normal permeabiltiy
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17
Q

What is the relationship between myelin and the propagation of action potentials

A

The presence of myelin greatly increases the propagation speed of action potentials

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18
Q

Which of the following axons is myelinated: one that propagates action potentials at 50 meters per second, or one that carries them at 1 meter per second

A

Action potentials travel along myelinated axons at much higher speeds. the axon with a propagation speed of 50 meters per second must be the myelinated axon

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19
Q

Describe the general structure of a synapse

A

Synapse = the site where a neuron communicates with another cell

structural components: presynaptic cell and a post synaptic cell, whose plasma membranes are separated by a post synaptic cleft

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20
Q

If the synapse involves direct physical contact between cells, it is termed ______; if the synapse involves a neurotransmitter, it is termed ____.

A

Direct physical contact = electrical synapse
neurotransmitter = chemical synapse

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21
Q

what effect would blocking voltage-gated calcium channels at a cholinergic synapse have on synaptic communication?

A

calcium would not be able to enter the presynaptic terminal and trigger the release of ACh into the synapse, so no communication would take place across the synapse

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21
Q

One pathway in the CNS consists of 3 neurons, another of 5 neurons. If the neurons in the 2 pathways are identical, which pathway would transmit impulses more rapidly?

A

Because of synaptic delay, the pathway with fewer neurons (3) will transmit impulses more rapidly

22
Q

Differentiate between a neurotransmitter and a neuromodulator

A

Both neurotransmitters and neuromodulators are compounds that are released by one neuron and affect another neuron. A neurotransmitter alters the transmembrane potential of the other neuron, whereas a neuromodulator alters the other neuron’s response to specific neurotransmitters

23
Q

Identify the 3 functional groups into which neurotransmitters and neuromodulators fall

A
  1. Compounds that have a direct effect on membrane potential
  2. Compounds that have an indirect effect on membrane potential
  3. Lipid-soluble gasses that exert their effects inside the cell
24
Q

One EPSP depolarizes the initial segment from a resting potential of -70mV to -65mV, and threshold is at -60mV. Will an action potential be generated?

A

No action potential will be generated.

25
Q

QUESTIONS 26 AND 27 ARE ABT ACTION POTENTIAL. LOOK BACK L8ER

A

LOOK BITCH

26
Q

Regulation by the nervous system provides…

A

swift, but brief, responses to stimuli

27
Q

in the CNS, a neuron typically receives information from other neurons at its……

A

dendrites

28
Q

Phagocytic cells in neural tissue of the CNS are…

A

microglia

29
Q

The neural tissues responsible for the analysis of sensory inputs and coordination of motor outputs are….

A

interneurons

30
Q

Depolarization of a neuron plasma membrane will shift the membrane potential toward…

A

0mV

31
Q

Which factor determines the direction that ions will move through an open membrane channel??

A

the electrochemical gradient

32
Q

Receptors that bind acetylcholine at the postsynaptic membrane are…

A

chemically gated channels

33
Q

What are the major components of the central nervous system and the peripheral nervous system?

A

CNS -brain and spinal cord
PNS - all neural tissue outside of the CNS

PNS consists of afferent and efferent division.
efferent division = SNS and ANS
afferent division= receptors and sensory neurons

34
Q

Which 2 types of neuroglia insulate neuron cell bodies and axons in the PNS from their surroundings?

A

Schwaan cells and satellite cells

35
Q

What 3 FUNCTIONAL groups of neurons are found in the nervous system? What is the function of each?

A

sensory neurons
interneurons
motor neurons

sensory neurons - transmit impulses from PNS to CNS

motor neurons - transmit impulses from the CNS to the peripheral effectors

interneurons - analyze sensory inputs and coordinate motor outputs

36
Q

If the resting membrane potential is -70mV and the threshold is -55mV, a membrane potential of -60mV will………

A

make it easier to produce an action potential (wont actually produce!)

37
Q

Why can’t most neurons in the CNS be replaced when they are lost to injury or disease?

A

Neurons lack centrioles and therefore cannot divide and replace themselves

38
Q

What is the difference between anterograde flow and retrograde flow?

A

Anterograde flow is the movement of materials from the cell body to the synaptic terminals. Retrograde flow is the movement of materials towards the cell body

39
Q

What is the FUNCTIONAL difference among voltage-gated, chemically-gated, and mechanically-gated channels?

A

voltage-gated channels open or close in response to changes in the transmembrane potential

chemically gated channels open or close when they bind specific extracellular chemicals

mechanically gated channels open or close in response to physical distortion of the membrane surface

40
Q

State the “all or none” principle of action potentials

A

any depolarization event sufficient to reach threshold will cause an action potential of the same strength, regardless of the amount of stimulation above the threshold

41
Q

Describe the steps involved in the generation of an action potential

A
  1. The membrane depolarizes to threshold
  2. Voltage-gated sodium channels are activated, and the membrane rapidly depolarizes
  3. The sodium channels are inactivated, and potassium channels are activated
  4. Normal permeability returns
42
Q

The voltage-gated sodium channels are activated once….

A

repolarization is complete

43
Q

The voltage-gated potassium channels begin closing as……

A

the transmembrane potential reaches the normal resting potential

44
Q

What is meant by saltatory propagation? How does it differ from continuous propagation?

A

saltatory propagation occurs in myelinated axons. Only the nodes along the axon can respond to a depolarizing stimulus.

continuous propagation occurs in unmyelinated axons. An action potential appears to move across the membrane surface in a series of tiny steps

45
Q

What are the structural and functional differences among type A, B , and C fibers?

A

Type A - myelinated and carry action potentials very quickly (120m/s)

Type B - also myelinated but carry action potentials more slowly due to their smaller diameter.

Type C fibers - extremely slow due to their small diameter and lack of myelination

46
Q

Describe the events that occur during nerve impulse transmission at a typical cholinergic synapse

A
  1. Action potential arrives at synaptic terminal, depolarizing it
  2. extracellular calcium enters the synaptic terminal, triggering the exocytosis of ACh
  3. ACh binds to the postsynaptic membrane and depolarizes the next neuron in the chain
  4. ACh is removed by AChE
47
Q

What is the difference between temporal summation and spacial summation

A

temporal summation - addition of stimuli that arrive at a single synapse in rapid succession

spatial summation - occurs when simultaneous stimuli at multiple synapses have a cumulative effect on the transmembrane potential

48
Q

Someone has a kidney condition that causes changes in the body’s electrolyte levels (concentration of ions in the extracellular fluid). As a result, he is exhibiting tachycardia. Which ion is involved, and how does its change in concentration cause these symptoms?

A

His kidney condition is causing the retention of K ions. As a result, the K concentration of the extracellular fluid is higher than normal. under these conditions, less potassium diffuses from the heart muscle cells than normal, resulting in a resting potential that is less negative (more positive). This change in resting potential moves the transmembrane potential closer to threshold, so it is easier to stimulate the muscle. the ease of stimulation accounts for the increased number of contractions (tachycardia)

49
Q

check #23 in book

A

check bish

50
Q

In multiple sclerosis, there is intermittent and progressive damage to the myelin sheath of peripheral nerves. This results in poor motor control of the affected area. WHY DOES DESTRUCTION OF THE MYELIN SHEATH AFFECT MOTOR CONTROL?

A

Action potentials travel faster along fibers that are myelinated. Destruction of the myelin sheath increases the time it takes for motor neurons to communicate with their effector muscles. This delay in response results in varying degrees of uncoordinated muscle activity. (similar situation as a newborn - they cannot control their arms and legs well because the myelin sheaths are still being laid down.)
Since not all motor neurons to the same muscle may be demyelinated to the same degree, there would be some fibers that are slow to respond while others are responding normally, producing contractions that are erratic and poorly controlled.

51
Q

What factor determines the maximum frequency of action potentials that could be conducted by an axon?

A

The absolute refractory period limits the number of action potentials that can travel along an axon in a given period of time. During the absolute refractory period, the membrane cannot conduct an action potential, so a new depolarization event cannot occur until the absolute refractory period has passed. If the absolute refractory period for a particular axon is 0.001sec, then the maximum frequency of action potentials conducted by this axon would be 1000/sec

52
Q
A

AP II Exam 1 (17 decks)

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