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

Question 1

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

Answer 1

brain; spinal cord

Question 2

Sensory/motor neurons gather information

Answer 2

Sensory

Question 3

Sensory/motor neurons control the muscles

Answer 3

Motor

Question 4

Four main parts of a neuron:

Answer 4

Soma, Axon, Dendrites, Terminal buttons

Question 5

Which part of the neuron contains the nucleus?

Answer 5

Soma

Question 6

Which part of the neuron receives messages from other neurons?

Answer 6

Dendrites

Question 7

Which part of the neuron secretes neurotransmitters?

Answer 7

Terminal buttons

Question 8

Define axoplasmic transport

Answer 8

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

Question 9

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

Answer 9

Anterograde

Question 10

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

Answer 10

Retrograde

Question 11

Which protein helps to accomplish anterograde axoplasmic transport?

Answer 11

Kinesin

Question 12

Which protein helps to accomplish retrograde axoplasmic transport?

Answer 12

Dynein

Question 13

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

Answer 13

False, retrograde is about two times slower than anterograde.

Question 14

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

Answer 14

Astrocytes, oligodendrocytes, microglia

Question 15

Role of astrocytes:

Answer 15

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

Question 16

Role of oligodendrocytes:

Answer 16

Provide support to axons, produce myelin sheath

Question 17

Role of microglia:

Answer 17

Phagocytosis, immune system, inflammatory reactions to bad microorganisms

Question 18

Schwann cells are located in the CNS/PNS

Answer 18

PNS

Question 19

Role of Schwann cells:

Answer 19

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

Question 20

What is the blood-brain barrier?

Answer 20

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

Question 21

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

Answer 21

Area Postrema

Question 22

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

Answer 22

vomiting

Question 23

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

Answer 23

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.

Question 24

The resting potential inside an axon is ____mV

Answer 24

-70

Question 25

What is membrane potential?

Answer 25

Any difference in charge across the membrane

Question 26

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

Answer 26

Hyperpolarization

Question 27

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

Answer 27

Depolarization

Question 28

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

Answer 28

Hyperpolarization

Question 29

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

Answer 29

Depolarization

Question 30

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

Answer 30

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

Question 31

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

Answer 31

depolarization; hyperpolarization

Question 32

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

Answer 32

diffusion; electrostatic pressure

Question 33

What is diffusion?

Answer 33

Molecules moving from high to low in order to achieve equilibrium

Question 34

What is electrostatic pressure?

Answer 34

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

Question 35

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.

Answer 35

True.

Question 36

Organic anion

Answer 36

A-

Question 37

Chloride ion

Answer 37

Cl-

Question 38

Sodium ion

Answer 38

Na+

Question 39

Potassium ion

Answer 39

K+

Question 40

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

Answer 40

intracellular

Question 41

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

Answer 41

in; back out

Question 42

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

Answer 42

in; in

Question 43

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

Answer 43

out; back in

Question 44

What does the sodium-potassium pump exchange?

Answer 44

Three sodium ions for two potassium ions

Question 45

The overall effect of the sodium-potassium pump:

Answer 45

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

Question 46

How to cause an action potential:

Answer 46

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.

Question 47

What determines the permeability of the membrane?

Answer 47

Ion channels

Question 48

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

Answer 48

Voltage; membrane potential

Question 49

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

Answer 49

Later

Question 50

All-or-none law

Answer 50

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.

Question 51

Rate law

Answer 51

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

Question 52

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

Answer 52

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