Chapter 7 - Nerve Cells and Electrical Signaling

Question 1

What are the two branches of the efferent nervous system?

Answer 1

somatic nervous system and autonomic nervous system

Question 2

Which part of the nervous system contains motor neurons that regulate skeletal muscle contractions?

Answer 2

somatic nervous system

Question 3

Which part of the nervous system is not under voluntary control?

Answer 3

autonomic nervous system

Question 4

What makes up the central nervous system?

Answer 4

brain and spinal cord

Question 5

90% of cells in the nervous system

Answer 5

glial cells

Question 6

functional units of the nervous system

Answer 6

neurons

Question 7

cells that produce action potentials

Answer 7

neurons

Question 8

branches of an axon

Answer 8

collateral

Question 9

site where the axon originates from the cell body

Answer 9

axon hillock

Question 10

What are the three parts of a neuron?

Answer 10

1. Cell body
2. Axon
3. Dendrite

Question 11

changes in membrane potential

Answer 11

action potential

Question 12

98% of neurons in the body

Answer 12

interneurons

Question 13

Which cells provide structural integrity to the nervous system?

Answer 13

glial cells

Question 14

_____ means “glue” in Latin.

Answer 14

Glia

Question 15

_____ enables neurons to transmit action potentials more efficiently and rapidly.

Answer 15

myelin

Question 16

Which two types of glial cells form Myelin?

Answer 16

Schwann cells & oligodendrocytes

Question 17

groups of cell bodies in the CNS

Answer 17

nuclei

Question 18

groups of cell bodies in the PNS

Answer 18

ganglia

Question 19

groups of axons in the CNS

Answer 19

pathways/tracts/commissures

Question 20

groups of axons in the PNS

Answer 20

nerves

Question 21

PNS

Answer 21

peripheral nervous system

Question 22

movement from axon terminal to cell body

Answer 22

retrograde transport

Question 23

movement from cell body to axon terminal

Answer 23

anterograde transport

Question 24

ion channel that is always open

Answer 24

leak channel or leaky channel

Question 25

ion channel that opens or closes in response to the binding of a chemical to a specific receptor in the plasma membrane

Answer 25

ligand-gated channel

Question 26

ion channel that opens or closes in response to changes in the membrane potential

Answer 26

voltage-gated channel

Question 27

In a resting membrane, _____ permeability is higher than _____.

Answer 27

potassium; sodium

Question 28

_____ channels open and close in response to mechanical force on the membrane.

Answer 28

Mechanically-gated

Question 29

_____ are excitatory and bring the membrane potential closer to threshold.

Answer 29

Depolarizations

Question 30

_____ are inhibitory and take the membrane potential further away from threshold.

Answer 30

Hyperpolarizations

Question 31

Threshold occurs when the flux of _____ ions exceeds the flux of _____ ions.

Answer 31

sodium; potassium

Question 32

During the _____ period, a second action potential cannot be stimulated.

Answer 32

absolute refractory

Question 33

During the _____ period, stronger stimuli can cause a second action potential.

Answer 33

relative refractory

Question 34

Action potentials cannot be produced where _____ is present.

Answer 34

myelin

Question 35

_____ refractory period prevents overlap of action potentials.

Answer 35

Absolute

Question 36

the jumping of action potentials from node to node

Answer 36

saltatory conduction

Question 37

In a myelinated neuron, action potentials are produced at the _____.

Answer 37

nodes of Ranvier

Question 38

When the membrane potential of a cell is at rest, which gates are open and/or closed?

Answer 38

The inactivation gate is open, and the activation gate is closed.

Question 39

What happens during depolarization?

Answer 39

The activation gate opens and sodium ions move into the cell.

Question 40

What happens 1 msec after a stimulus?

Answer 40

The inactivation gate closes, and remains closed until membrane potential returns to resting.

Question 41

The relative refractory period is primarily due to the increased _____.

Answer 41

permeability to potassium

Question 42

The rising phase of an action potential lasts approximately _____.

Answer 42

0.5 ms

Question 43

The repolarization phase of an action potential lasts approximately _____.

Answer 43

0.5 ms

Question 44

During an action potential, hyperpolarization lasts approximately _____.

Answer 44

2 ms

Question 45

The _____ creates the concentration gradient.

Answer 45

sodium/potassium pump

Question 46

Action potentials occur in response to graded potentials that _____.

Answer 46

reach threshold