Chapter 3

Question 1

What is a neuron?

Answer 1

the specialized conducting cell of the nervous system

Question 2

What is a dendrite?

Answer 2

branchlike or root like extensions from a neuron that connect to other neurons or axons to RECEIVE INFORMATION

Question 3

What is an axon?

Answer 3

Extension of a neuron used to CONDUCT electrical impulses

Question 4

What is a Glial cell?

Answer 4

it is the support cell of the nervous system

Question 5

What do Glial cells do?

Answer 5

surround neurons and hold them in place

manufacture nutrient chemicals

absorb toxins and waste

Question 6

Explain what a tripartite synapse includes?

Answer 6

presynaptic axon

postsynaptic dendrite

Glial cell that surrounds the area and helps clear the neurotransmitters more efficitently

Question 7

What is the absolute refractory period?

Answer 7

the time when the membrane is not excitable and cannot generate another action potential

Question 8

What is the action potential threshold?

Answer 8

-55mv

needs to change from -70 to -55 in order to trigger action potential (minimum change)

Question 9

What is the all or none law?

Answer 9

action potentials occur at a uniform and maximum intensity or they do not occur at all

Question 10

Explain the resting state of a neurons membrane

Answer 10

Abundant Na+ outside membrane and K+ and negative molecules inside.

creates a resting potential of -70mV

Question 11

explain the process of an axon stimulating a dendrite

Answer 11

action potential travels down the axon.

the change in voltage of the axon terminal from -70 mV to +40 mv triggers the release of neurotransmitters from synaptic vesicles in the axon terminal into the synaptic cleft

these neurotransmitters then quickly diffuse across the synaptic cleft and bind to receptor proteins in the dendritic membrane.

these proteins then trigger the opening of gated Na+ channels to generate an action potential in the dendrite

Question 12

What is a graded potential?

Answer 12

it is when the membrane depolarizes slightly, but not enough to reach the action potential threshold and thus not enough to generate an action potential

Question 13

What is a myelin sheath?

Answer 13

a fatty white layer of insulation derived from glial cells during development

Question 14

What is a node of ranvier?

Answer 14

an area where the myelin is either extremely thin or absent..

Question 15

What does multiple sclerosis do?

Answer 15

it is when the immune system attacks the myelin sheath

Question 16

What is an excitatory transmitter?

Answer 16

A neurotransmitter that depolarizes the neuron’s membrane when it binds to a receptor protein by opening Na+ channels

Question 17

What is an inhibitory neurotransmitter?

Answer 17

a neurotransmitter that causes the neuron to hyperpolarize by allowing k+ to flow out or negative ions to flow in making it more negative

makes it more difficult for the action potential threshold to be reached

allows fine tuning and reduces the chance of uncoordinated discharges

Question 18

At what point is the action potential threshold?

Answer 18

-55mV

Question 19

What are the two ways that a neurotransmitter can be deactivated?

Answer 19

Breakdown by chemicals in the synaptic cleft

Reuptake into the pre synaptic axon terminal

Question 20

approximately how many neurotransmitters are there?

Answer 20

100-150

Question 21

What does acetylcholine affect?

Answer 21

memory and muscle activity

underproduction of ACh linked to Alzheimer’s

botulism blocks it at muscles resulting in paralysis

it is excitatory

Question 22

What does dopamine do?

Answer 22

many things including:
motivation, reward, pleasure, voluntary motor control

it is excitatory

Question 23

What neurotransmitter does Parkinson’s disease deplete?

Answer 23

dopamine

Question 24

What does serotonin influence?

Answer 24

mood, eating, sleep, and sexual behaviour

Question 25

What does the medication Prozac do?

Answer 25

block the reuptake of serotonin to allow it to exert its effects for longer

Question 26

What do endorphins do?

Answer 26

block pain and increase feelings of well being

Question 27

explain the difference between neurotransmitters and neuromodulaters

Answer 27

neurotransmitters have a very specific effect that effect a very specific area

neuromodulators have a generalized effect of enhancing or inhibiting receptors that is widespread over a large area often the whole brain