Chapter 34 The Nervous System

Front 1

Name the 4 basic functions of the Nervous System

Back 1

1)percieve a stimulus
2)transform it into an "impulse"
3)conduct the impulse
4)trigger a response or not (selective to the stimuli you percieve)

Front 2

The nervous system is composed of neurons and associated cells, and the functions are reflected in the structural arrangements of _______, ____________, and ___________ into pathways

Back 2

neurons, receptor cells, effector cells

Front 3

Function of a dendrite

Back 3

recieve signals

Front 4

Function of an axon

Back 4

conducts signals

Front 5

Function of a cell body

Back 5

holds ions and decides whether to conduct a stimulus or not

Front 6

Function of sensory neuron

Back 6

(receptor cells) picks up sensation or stimulus and conducts it to an interneuron

Front 7

Function of association (interneuron)

Back 7

in b/w sensory and motor decision making to respond or not, found in CNS

Front 8

Function of motor neuron

Back 8

carries out the response by stimulating the effector cell, found in the PNS

Front 9

Function of the effector cell

Back 9

muscle or anything actually stimulated

Front 10

Reflex arc

Back 10

simplest pathway, contains only 2 neurons, one sensory and one motor, doesnt have to travel all the way to the brain for a reflex, used a defense mechanism

Front 11

Difference b/w divergent and convergent pathways

Back 11

Divergent- one neuron affects many
Convergent- alot of pathways are converging upon one neuron

Front 12

What is a resting potential?

Back 12

potential to do work

Front 13

Why do all living cells have a negative resting potential?

Back 13

needs to be negative to have the ability to conduct an impulse

Front 14

What 2 forces maintain this distribution of charged ions

Back 14

1) attractions of (-) and (+) charges high concentration
2) diffusion

Front 15

What is an action potential?

Back 15

Na+ rushes in and K+ rushes out (gates open)and makes the inside (+)

Front 16

What events occur in quick succession during an action potential?

Back 16

depolarization-goes from (-) and (+) inside Na goes in
repolarization-return to (-) inside the cell
travels down the axon to the bouton and diffuses to the next dendrite

Front 17

How is the ion distribution inside the cell and outside the cell returned to the original state so the cell is always ready for an action potential

Back 17

the Na/K pump uses active transport restores the correct ion distribution (repolarization)

Front 18

Why does repolarization require energy?

Back 18

active transport- uses atp to move things against the concentration gradient, requires a transport protein

Front 19

How is impulse conduction along an axon speeded up when satellite cells are present?

Back 19

they allow the impulse to skip from node to node instead of all the way down the axon

Front 20

What are the 3 functions of satellite cells?

Back 20

1)give physical support and protection
2) help nourish the neurons
3)provide insulation and speed up conduction (50X) faster if mylenated

Front 21

How are impulses conducted across the synaptic gap?

Back 21

action potential goes from electrochemical to just chemical thru diffusion, neurotransmitter, ion channels open and recieve the right neurotransmitters

Front 22

What is a bouton?

Back 22

end of an axon swollen

Front 23

What are vesicles?

Back 23

store neurotransmitters

Front 24

Name some neurotransmitters produced by the nervous system.

Back 24

epinephrine(organs and involuntary muscle)
serotonin (pain, mood, sleep)
dopamine (stimulates hypothalamus)
GABA (major inhibitory)

Front 25

Which is the one neurotransmitter used primarily in teh stimulation of skeletal muscle?

Back 25

acetylcholine- prominent in many CNS synapses

Front 26

How are neurotransmitters removed from the gap after conduction?

Back 26

some simply diffuse away
some actively taken back up by the presynaptic axon
some is broken down by an enzyme

Front 27

Which is faster: a conduction along the length of an axon, or conduction across the tiny synaptic gap?

Back 27

axon b/c there is no diffusion

Front 28

Why can impulses only travel in one direction along a neural pathway?

Back 28

1)only one end of the neuron has neurotransmitters
2)axon doesnt recieve a stimulus
3) impulse cant double back due to refractory period (recovery time from de/repolarizing

Front 29

What is meant by intergration of signals that occurs in the cell body?

Back 29

summing up exhibitory and inhibitory signals to see if an action potential occurs