Animal Nervous system

Question 1

neuron

Answer 1

transmits chemical signals

Question 2

dendrites

Answer 2

convert chemical signals to electrical signals

Question 3

cell body (soma)

Answer 3

contains nucleus, integrates incoming electrical signals

Question 4

axon

Answer 4

conducts electrical signals

Question 5

resting potential

Answer 5

when a neuron is not communicating with other cells, the difference in charge across its membrane is called resting potential

Question 6

Does a neuron have a negative or positive resting membrane potential?

Answer 6

negative

Question 7

action potential

Answer 7

rapid, temporary change in a membrane potential

Question 8

depolarization

Answer 8

membrane potential changes from highly negative to briefly positive

Question 9

repolarization

Answer 9

changes membrane potential back to negative

Question 10

hyperpolarization

Answer 10

when membrane potential is slightly more negative than resting potential

Question 11

threshold potential

Answer 11

membrane potential will trigger an action potential in a neuron or other excitable cell

Question 12

refractory state

Answer 12

once Na+ channels have opened and closed, they are less likely to open again for a short period

Question 13

voltage-gated ion channels

Answer 13

membrane proteins that open and close in response to changes in membrane voltage

Question 14

Ligand-gated channels

Answer 14

have binding site for specific ligand on part of channel protein that faces synaptic cleft

Question 15

Synapses

Answer 15

tiny spaces at junctions of neurons that separate them from one another

Question 16

Neurotransmitters

Answer 16

chemical messengers that transmit information from one neuron to another neuron or from a neuron to a target cell in a muscle or gland

Question 17

Synaptic cleft

Answer 17

tiny space that separates membranes of axons and cells that they communicate with

Question 18

Presynaptic neuron

Answer 18

neuron that contains synaptic vesicles

Question 19

Postsynaptic cell

Answer 19

cell on other side of synaptic cleft

Question 20

Ligand

Answer 20

a molecule that binds to a specific site on a receptor molecule

Question 21

Inhibitory postsynaptic potentials (IPSP)

Answer 21

changes in membrane potential of postsynaptic cell that make cells less likely to produce an action potential

Question 22

Excitatory postsynaptic potentials (EPSP)

Answer 22

changes in potential of postsynaptic cell that make cell more likely to produce an action potential

Question 23

Myelination

Answer 23

formation of myelin sheath around a nerve to allow for improved conduction

Question 24

Schwann cells

Answer 24

specialized accessory cells whose membranes wrap around axon of certain neurons, form myelin sheath

Question 25

Myelin sheath

Answer 25

acts as type of electrical insulation

Question 26

Node of ranvier

Answer 26

gap in myelin sheath

Question 27

Neurotoxins

Answer 27

poisons that affect neuron function, often resulting in convulsions, paralysis, or unconsciousness