Ch 3- neurons and neural transmission

Question 1

sensory neurons

Answer 1

make initial contact with the environment and are responsible for carrying the message inward toward the spinal cord and brain

Question 2

interneurons

Answer 2

most plentiful type of neuron, make no direct contact with the world but they convey information from one internal processing site to another

Question 3

motor neurons

Answer 3

carry messages and commands away from central nervous system to the muscles and glands that produce responses

Question 4

glial cells

Answer 4

cells that fill in space between neurons, remove waste, or help neurons to communicate efficiently

Question 5

myelin sheath

Answer 5

an insulating material that protects the axon and helps to speed up neural transmission

Question 6

reflexes

Answer 6

largely automatic body actions- such as the knee jerk- that are controlled primarily by spinal cord pathways

Question 7

dendrites

Answer 7

look like tree branches. primary information receivers,

Question 8

soma

Answer 8

cell body of the neuron, also called metabolic center, where genetic material is stored

Question 9

axon

Answer 9

the long tail-like part of a neuron that serves as the cell’s transmitter. the electric signal called the action potential travels down the axon

Question 10

terminal buttons

Answer 10

the tiny swellings at the end of the axon that contain chemicals important to neural transmission

Question 11

synapse

Answer 11

small gap between the terminal buttons of a neuron and the dendrite or cell body of another neuron

Question 12

direction of information flow in a neuron

Answer 12

dendrites, soma, axon, terminal buttons

Question 13

Messages travel ___ from one point to another within a neuron, but the message is transmitted ____ between neurons.

Answer 13

electrically, chemically

Question 14

resting potential

Answer 14

the tiny electrical charge in place between the inside and the outside of the resting neuron

Question 15

main ions in neural transmission

Answer 15

positively charged sodium and potassium and negatively charged chloride

Question 16

action potential

Answer 16

the all-or-none electrical signal that travels down a neuron’s axon

Question 17

excitatory message

Answer 17

ion channels open, sodium ions flow into the cell (depolarization), moves electrical potential of cell from negative to 0

Question 18

inhibitory message

Answer 18

cell membrane pushes more positive ions out of the cell or allows negative ions to move in (hyperpolarization), electrical potential of the cell becomes more negative

Question 19

axon hillock

Answer 19

near the point where the axon leaves the cell body, all of the excitatory and inhibitory potentials combine.

Question 20

When will a cell “fire” an action potential?

Answer 20

If enough excitatory messages have been received (aka the net electrical potential inside the cell has become sufficiently less negative)

Question 21

Nodes of ranvier

Answer 21

the gaps in insulation (myelin sheath) that permit action potential to jump down the axon rather than travel from point to point

Question 22

neurotransmitters

Answer 22

chemical messengers that relay information from one neuron to the next

Question 23

glutamate

Answer 23

most common neurotransmitter in the brain, excitatory neurotransmitter, involved in memory

Question 24

acetylcholine

Answer 24

a neurotransmitter that plays multiple roles in the central and peripheral nervous systems, including excitation of muscle contractions

Question 25

dopamine

Answer 25

a neurotransmitter that has been linked to reward and pleasure systems in the brain (usually inhibitory); helps us sleep without physically acting out our dreams; decreased levels have been linked to Parkinson disease, and increased levels have been linked to schizophrenia.

Question 26

serotonin

Answer 26

a inhibitory neurotransmitter that has been linked to sleep, dreaming, and general arousal and may also be involved in some psychological disorders such as depression and schizophrenia.

Question 27

GABA (gamma-amino-butyric acid)

Answer 27

an inhibitory neurotransmitter that may play a role in the regulation of anxiety

Question 28

agonists

Answer 28

drugs that enhance or mimic the action of neurotransmitters (ex. nicotine-acetylcholine, cocaine-dopamine)

Question 29

antagonists

Answer 29

drugs that block the action of neurotransmitters (ex. curare-acetylcholine)

Question 30

endorphins

Answer 30

morphine-like chemicals that act as the brain’s natural painkillers

Question 31

refractory period

Answer 31

the period of time following an action potential when more action potentials cannot be generated