Ch 45: Nervous System

Question 1

Neurons

Answer 1

Excitable cells
Cells that communicate with each other and other cells in the body through electrical and chemical signals
Functional cells of the nervous system
Initiate, receive, and process electrical activities

Question 2

Electricity

Answer 2

Movement of electrons

In the body - the movement of ions across the plasma membrane

Question 3

Soma

Answer 3

Area of the cell that directs all of the neuronal activities
Control part of the cell
Holds the nucleus

Question 4

Dendrites

Answer 4

Extensions from the cell body
Receptive sites for electrical signals
Allow neurons to have multiple connections
Increase surface area for interaction

Question 5

Axon hillock

Answer 5

Single major branch that connects the soma with the axon

Initiates the action potential

Question 6

Axon

Answer 6

Part of the neuron that transmits the electrical signal away from the cell body
Conducts signal away from the soma
Nerve fibers

Question 7

Axon terminals

Answer 7

Site where neurotransmitters are located

Vesicles of neurotransmitters bing to the membrane and are released

Question 8

Schwann cells

Answer 8

Cells that produce myelin sheaths that insulate the axon

Question 9

Nodes of Ranvier

Answer 9

Gaps in myelin sheaths along the axon
Hold a lot of sodium and potassium channels
No myelin
There is a jump from node to node

Question 10

Myelin

Answer 10

Lipid insulator

Contains electrical activity

Question 11

Afferent neurons

Answer 11

Neurons that send into of the CNS

Question 12

Interneurons

Answer 12

Neurons that connect neurons within the CNS

Question 13

Efferent neurons

Answer 13

Neurons that send information from the CNS

Motor neurons

Question 14

Synapse

Answer 14

Where two neurons form a junction

Pre synaptic neuron meets a post synaptic neuron

Question 15

Action potential

Answer 15

Ionic movement

Ability for ions to move across the membrane

Question 16

Threshold

Answer 16

The all or nothing action potential point

When 600x more VGSC open

Question 17

Depolarization

Answer 17

When membrane potential is less negative than resting potential

Question 18

Hyperpolarization

Answer 18

When membrane potential is more negative than resting potential

Question 19

Repolarization

Answer 19

When membrane potential returns to its resting potential - either from depolarization or hyperpolarization

Question 20

Voltage gated sodium channels

Answer 20

Protein channel that is specific to sodium
Triggered to open at threshold
Has three states: closed, open, and inactivated

Question 21

Voltage gated potassium channels

Answer 21

A protein channel that is specific to potassium
Triggered to open at the peak
Has two states: closed and open
Does not open when sodium channels are open

Question 22

Refractory period

Answer 22

Amount of time that VGSC are inactivated

Everything after peak and before next action potential

Question 23

Oligodendrocytes

Answer 23

Cells that make myelin in the CNS

Can mylenate multiple cells at once

Question 24

Cell body

Answer 24

Perikaryon

Abundant protein synthesis organelle

Question 25

Schwann cells

Answer 25

Cells that make myelin in the PNS