Chapter 2: Structures and Functions of Cells of the Nervous System Flashcards

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1
Q

The CNS is made up of the ______ and the _______.

A

brain; spinal cord

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2
Q

Sensory/motor neurons gather information

A

Sensory

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3
Q

Sensory/motor neurons control the muscles

A

Motor

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4
Q

Four main parts of a neuron:

A

Soma, Axon, Dendrites, Terminal buttons

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5
Q

Which part of the neuron contains the nucleus?

A

Soma

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6
Q

Which part of the neuron receives messages from other neurons?

A

Dendrites

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7
Q

Which part of the neuron secretes neurotransmitters?

A

Terminal buttons

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8
Q

Define axoplasmic transport

A

An active process that propels substances along microtubule “tracks” that run inside the length of the axon

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9
Q

Anterograde/retrograde axoplasmic transport propels substances from the soma to the terminal buttons.

A

Anterograde

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10
Q

Anterograde/retrograde axoplasmic transport propels substances from the terminal buttons to the soma.

A

Retrograde

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11
Q

Which protein helps to accomplish anterograde axoplasmic transport?

A

Kinesin

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12
Q

Which protein helps to accomplish retrograde axoplasmic transport?

A

Dynein

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13
Q

True or False: Anterograde axoplasmic transport is considerably slower than retrograde axoplasmic transport.

A

False, retrograde is about two times slower than anterograde.

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14
Q

What are the three types of glial cells in the CNS?

A

Astrocytes, oligodendrocytes, microglia

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15
Q

Role of astrocytes:

A

physically support neurons by acting like glue, clean up debris in brain via phagocytosis, produce chemicals and provide nutrients

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16
Q

Role of oligodendrocytes:

A

Provide support to axons, produce myelin sheath

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17
Q

Role of microglia:

A

Phagocytosis, immune system, inflammatory reactions to bad microorganisms

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18
Q

Schwann cells are located in the CNS/PNS

A

PNS

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19
Q

Role of Schwann cells:

A

support axons, produce myelin, digest dying axons and help regrow axon

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20
Q

What is the blood-brain barrier?

A

A selectively permeable barrier with no gaps that regulates the composition of extracellular fluid and keeps messages from being disrupted

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21
Q

What is the weak part of the blood-brain barrier called?

A

Area Postrema

22
Q

The area postrema controls ______ by detecting toxic substances entering the blood

A

vomiting

23
Q

Describe a basic communication within a neuron when grabbing a BURNING HOT thing

A

When sensory dendrites are stimulated, it sends messages down the axon to terminal buttons, which release neurotransmitters, which excite the motor neuron, causing the muscle cells to contract.

24
Q

The resting potential inside an axon is ____mV

A

-70

25
Q

What is membrane potential?

A

Any difference in charge across the membrane

26
Q

When there is an increase in membrane potential, ___________ occurs.

A

Hyperpolarization

27
Q

When there is a decrease in membrane potential, _________ occurs.

A

Depolarization

28
Q

When the inside charge becomes more negative and the outside charge becomes more positive, then _______ occurs.

A

Hyperpolarization

29
Q

When the inside charge becomes more positive and the outside charge becomes more negative, then ________ occurs.

A

Depolarization

30
Q

Each neuron has a threshold of excitement, which is _________.

A

the set point that must be reached in order to produce an action potential

31
Q

An action potential is a burst of rapid ______ followed by _________.

A

depolarization; hyperpolarization

32
Q

The electrical charge of the membrane potential is the result of a balance between two opposing forces, namely _______ and _______.

A

diffusion; electrostatic pressure

33
Q

What is diffusion?

A

Molecules moving from high to low in order to achieve equilibrium

34
Q

What is electrostatic pressure?

A

The force exerted by the attraction/repulsion of ions. Opposites attract; likes repulse.

35
Q

True or False: The forces of diffusion and electrostatic pressure contributed by the intracellular fluid and the extracellular fluid ions give rise to the membrane potential.

A

True.

36
Q

Organic anion

A

A-

37
Q

Chloride ion

A

Cl-

38
Q

Sodium ion

A

Na+

39
Q

Potassium ion

A

K+

40
Q

A- are located only in the _________ fluid because the membrane is impermeable to them.

A

intracellular

41
Q

Diffusion pushes CI- ___ and electrostatic pressure pushes CI- ___.

A

in; back out

42
Q

Diffusion pushes Na+ ___ and electrostatic pressure pushes Na+ ___

A

in; in

43
Q

Diffusion pushes K+ ___ and electrostatic pressure pushes K+ ___

A

out; back in

44
Q

What does the sodium-potassium pump exchange?

A

Three sodium ions for two potassium ions

45
Q

The overall effect of the sodium-potassium pump:

A

Keeps the intracellular fluid concentration of Na+ out while slightly increasing K+ inside

46
Q

How to cause an action potential:

A

Briefly increase the membrane permeability to Na+ (allowing these ions to rush into the cell), immediately follow this with a transient increase in the permeability of the membrane to K+ (allowing them to rush out of the cell). This is achieved via ion channels.

47
Q

What determines the permeability of the membrane?

A

Ion channels

48
Q

Both sodium and potassium channels are _______-dependent and can only be opened by changes in the ______ _______.

A

Voltage; membrane potential

49
Q

Because potassium channels are not as sensitive as sodium channels, they open earlier/later.

A

Later

50
Q

All-or-none law

A

the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus. If a stimulus is above a certain threshold, a nerve or muscle fiber will fire.

51
Q

Rate law

A

High firing rate = strong intensity (bowling ball)
Low firing rate = light intensity (feather)

52
Q

True or False: Myelinated segments completely close the axon off from extracellular fluid

A

True, so there is no inward flow of Na+ in these areas.