Ch 45: Nervous System Flashcards Preview

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Flashcards in Ch 45: Nervous System Deck (25):
1

Neurons

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

2

Electricity

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

3

Soma

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

4

Dendrites

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

5

Axon hillock

Single major branch that connects the soma with the axon
Initiates the action potential

6

Axon

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

7

Axon terminals

Site where neurotransmitters are located
Vesicles of neurotransmitters bing to the membrane and are released

8

Schwann cells

Cells that produce myelin sheaths that insulate the axon

9

Nodes of Ranvier

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

10

Myelin

Lipid insulator
Contains electrical activity

11

Afferent neurons

Neurons that send into of the CNS

12

Interneurons

Neurons that connect neurons within the CNS

13

Efferent neurons

Neurons that send information from the CNS
Motor neurons

14

Synapse

Where two neurons form a junction
Pre synaptic neuron meets a post synaptic neuron

15

Action potential

Ionic movement
Ability for ions to move across the membrane

16

Threshold

The all or nothing action potential point
When 600x more VGSC open

17

Depolarization

When membrane potential is less negative than resting potential

18

Hyperpolarization

When membrane potential is more negative than resting potential

19

Repolarization

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

20

Voltage gated sodium channels

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

21

Voltage gated potassium channels

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

22

Refractory period

Amount of time that VGSC are inactivated
Everything after peak and before next action potential

23

Oligodendrocytes

Cells that make myelin in the CNS
Can mylenate multiple cells at once

24

Cell body

Perikaryon
Abundant protein synthesis organelle

25

Schwann cells

Cells that make myelin in the PNS