Neural Tissue and Physiology Part 2 (End of Exam 3)

Question 1

How does sodium flow into the cell if the membrane is so impermeable to it?

Answer 1

Opening of specific membrane channels

Question 2

What are the 2 types of gated membrane channels?

Answer 2

Voltage gated and chemically gated

Question 3

Where are chemically gated channels found?

Answer 3

Soma

Question 4

Where are voltage gated channels found?

Answer 4

Axon

Question 5

Leak channels that are always open

Answer 5

Passive channels

Question 6

Gated channels that ope and close in response to stimuli

Answer 6

Active channels

Question 7

Are active channels ope or close at resting potential?

Answer 7

Closed

Question 8

Variable strength electrical signals that travel over short distances and lose strength as they travel away from the source

Answer 8

Graded potential

Question 9

What causes a graded potential?

Answer 9

Opening and closing of gated channels

Question 10

What are graded potentials used for?

Answer 10

Short distance communication in neurons

Question 11

Where do graded potentials occur? (3)

Answer 11

Dendrites, somas, synaptic terminals

Question 12

The greater the stimulus the ____ changed in transmembrane potential and ____ area affected

Answer 12

More, more

Question 13

What are graded potentials at opposite ends of cells linked by?

Answer 13

Action potential

Question 14

Large uniform electric signals that can travel great distance without losing strength

Answer 14

Action potential

Question 15

What causes action potentials?

Answer 15

Opening and closing of voltage gated channels when threshold potential is reached

Question 16

Where do action potentials occur?

Answer 16

Axons

Question 17

Action potential is triggered or not; only occurs when threshold is reached

Answer 17

All or none

Question 18

What is the threshold level of voltage gated sodium channels

Answer 18

-60 to -55 mV

Question 19

What is the 1st step in producing an action potential?

Answer 19

Graded depolarization brings an area of excitable membrane to threshold

Question 20

What is the 2nd step in producing an action potential?

Answer 20

Activation of sodium channels causes rapid depolarization, Na+ rush into the cytoplasm, inner membrane changes from negative to positive

Question 21

What is the 3rd step in producing an action potential?

Answer 21

Closing of sodium gated channels, opening of potassium gated channels; repolarization

Question 22

What is the 4th step in producing an action potential?

Answer 22

Potassium channels close when membrane reaches resting potential, membrane is hyperpolarized to -90 mV and returns to resting potential

Question 23

What are the 2 types of propagation?

Answer 23

Continuous, saltatory

Question 24

Unmyelinated axons in propagation?

Answer 24

Continuous

Question 25

Myelinated axons in propagation?

Answer 25

Saltatory

Question 26

Direct physical contact between cells

Answer 26

Electrical synapses

Question 27

Signal transmitted across a gap by chemical neurotransmitters

Answer 27

Chemical synapses

Question 28

What determines whether an action potential may or may not be propagated to the postsynaptic cell?

Answer 28

Amount and type of neurotransmitter released

Question 29

Neurotransmitters that cause depolarization of postsynaptic membrane, promotes action potentials

Answer 29

Excitatory

Question 30

Neurotransmitters that cause hyperpolarization of postsynaptic membranes, suppress action potentials

Answer 30

Inhibitory

Question 31

What does the effect of a neurotransmitter depend on ?

Answer 31

Receptor

Question 32

Any synapse that releases ACh

Answer 32

Cholinergic synapse

Question 33

Graded potentials developed in a postsynaptic cell in response to neurotransmitters

Answer 33

Postsynaptic potentials

Question 34

Graded depolarization of postsynaptic membrane

Answer 34

Excitatory postsynaptic potential

Question 35

Graded hyper polarization of postsynaptic membrane

Answer 35

Inhibitory postsynaptic potential

Question 36

Repeated stimuli at one synapse

Answer 36

Temporal summation

Question 37

Many stimuli arrive at multiple synapses

Answer 37

Spatial summation