Nervous System

Front 1

neurons

Back 1

nerve cells

Front 2

soma

Back 2

cell body of neurons

Front 3

dendrites and axons

Back 3

processes extending from the soma of neurons

Front 4

how many dendrites and axons are in a neuron?

Back 4

one axon only but several dendrites

Front 5

what do neurons do?

Back 5

It receives impulses at its dendrites and transmits the impulse through the cell body and down the axon

Front 6

When a neuron is polarized, it is_________

Back 6

resting. The inside is negatively charged compared to the outside of the neuron

Front 7

the resting membrane potential is ____mV and its definition is__________

Back 7

-70mV
it is the difference in charge between the outside and the inside of the neuron

Front 8

what are the 2 membrane proteins?

Back 8

sodium-potassium pump and the leak channels

Front 9

What does the sodium-potassium pump do?

Back 9

It uses one molecule of ATP to move 3 sodium ions out of the cell while simultaneously moving 2 potassium ions into the cell

Front 10

Are the sodium and potassium ions negative or positive?

Back 10

positive

Front 11

What do the leak channels do?

Back 11

They let potassium ions leak out from the inside of the cell according to its gradient

Front 12

Why does a neuron have a resting membrane potential of -70mV?

Back 12

because the sodium-potassium pump and the leak channels let a lot of positive ions leave and cell and so a lot of negative stuff (DNA, RNA and proteins) are left behind.

Front 13

What are voltage gated channels?

Back 13

channels that open when the cell membrane reaches a particular voltage

Front 14

The potential at which the voltage-gated channels open is ________

Back 14

threshold potential

Front 15

2 types of voltage-gated channels are:

Back 15

sodium and potassium voltage-gated channels

Front 16

The membrane potential moves in the postive direction

Back 16

depolarization

Front 17

The membrane potential returns to its negative value

Back 17

repolarization

Front 18

What is an impulse?

Back 18

a traveling action potential

Front 19

action potential travels in what direction?

Back 19

down the axon

Front 20

What are the steps in an action potential?

Back 20

1) A neuron is polarized (-70mV) and depolarizes slightly to -50mV. The sodium and potassium voltage-gated channels then opens.

2) sodium v-g channel opens first and sodium ions enter according to its concentration gradient previously established by the Na+K+ ATPase pump

3) The sodium ions depolarizes the cell until it reaches the maxium of +35mV. The Na+ v-g channel then closes

4) the K+ v-g channel opens and K+ exits the cell according to its concentration gradient

5) The cell is repolarized to -90mV before the K+ channels close

6) the Na+ K+ ATPase and leak channels return the cell to its resting polarized state.

Front 21

sometimes the axon is wrapped with special cells called ________. This entire wrapping is a _____________

Back 21

schwann cells

myelin sheath

Front 22

Node of Ranvier

Back 22

spaces between the Schwann cells

Front 23

What is saltatory conduction?

Back 23

a jumping type of conduction where the impulse jumps from nodes to nodes. This increases the speed in which the impulse can travel down the axon

Front 24

What is a refractory period?

Back 24

the period after firing an action potential where the portion of the membrane is unable to fire another action potential. This ensures that the action potential will only travel in one direction

Front 25

What is a synapse?

Back 25

an neuron to neuron junction or a neuron to organ junction

Front 26

What is a neurotransmitter?

Back 26

a chemical that passes an impulse from one neuro to the next

Front 27

The gap between the axon and the dendrite of another neuron

Back 27

synaptic cleft

Front 28

The neurotransmitter is in vesicles and it is released into hte synaptic cleft by _______

Back 28

exocytosis

Front 29

When a cell is ________it depolarizes toward the threshold

Back 29

stimulated

Front 30

When a cell is _________it moves away from the threshold

Back 30

inhibited

Front 31

What is summation?

Back 31

A neuron taking all of the stimulatory input and inhibitory input and adding them up to determine if it will fire an action potential

Front 32

The most common neurotransmitter in the body

Back 32

acetylcholine

Front 33

The brain and the spinal chord are part of the _____________ system

Back 33

central nervous

Front 34

neurons completey within the brain and the spinal chord and connect sensory and motor neurons

Back 34

interneurons

Front 35

neurons that send info to the CNS from the sensory organs

Back 35

sensory neurons

Front 36

neurons that send info from the CNS to muscles and glands

Back 36

motor neurons

Front 37

motor and sensory neurons are part of the

Back 37

peripheral nervous system

Front 38

interneurons are part of the

Back 38

CNS

Front 39

the 2 divisions of the PNS are:

Back 39

the somatic nervous system and the autonomic nervous syste

Front 40

The skeletal muscles are controlled by the _______ nervous system

Back 40

somatic

Front 41

acetylcholine is used by the ________ system and the ______ division as a neurotransmitter

Back 41

somatic nervous, parasympathetic

Front 42

the autonomic nervous system is divided into:

Back 42

sympathetic division and parasympthatic division

Front 43

What is the fight or flight system?

Back 43

sympathetic division

Front 44

What is the resting and digesting system?

Back 44

parasympathetic division

Front 45

This is where voluntary actions such as movement, speech etc. occur

Back 45

cerebrum

Front 46

this part of the brain coordinates balance and muscle movement

Back 46

cerebellum

Front 47

this primitive part of the brain regulates breathing and blood pressure

Back 47

medulla

Front 48

this part of the brain monitors hormone levels, temperature and electrolyte balance

Back 48

hypothalamus