Ch 48-49 Nervous System

Question 1

Neurons

Answer 1

Nerve cells

Question 2

Where do neurons receive signals?

Answer 2

Their dendrites

Question 3

What structure do signals received by neurons travel down?

Answer 3

The axon

This allows for rapid communication

Question 4

Afferent nerves (sensory nerves)

Answer 4

Carry signals to the brain or central nervous system

Question 5

Efferent nerves (motor nerves)

Answer 5

Carry signals out from the central nervous system

Question 6

Resting membrane potential (-70 mV)

Answer 6

When a nerve is at rest it has a negative charge internally and positive charge externally

Question 7

Action potential

Answer 7

An electrical signal that moves along the axon

Question 8

What causes depolarization?

Answer 8

A stimulus at the dendrite end of the cell opening sodium channels

Question 9

Depolarization

Answer 9

A change in the direction of the membrane potential

Question 10

What does depolarization trigger?

Answer 10

Repolarization

Question 11

Repolarization

Answer 11

Potassium ion movement out of the neuron

Question 12

What does repolarization trigger?

Answer 12

Depolarization of the adjacent region

Question 13

Why is an action potential considered an “all or nothing” response?

Answer 13

All action potentials are identical and, once triggered, go to completion

Question 14

Synapses

Answer 14

Transmit action potentials between nerve cells

Question 15

Neurotransmitters

Answer 15

Communicate transmission across synapses (electrical or chemical)

Question 16

What is triggered when one neurotransmitter is released by one nerve?

Answer 16

The opening of ion channels on the next nerve

If enough channels open, the nerve will depolarize and pass along its own action potential

Question 17

Central nervous system (CNS)

Answer 17

Possessed by bilateral animals

Question 18

The central nervous system (CNS) communicates with what?

Answer 18

A peripheral nervous system (PNS)

Question 19

Reflex arc

Answer 19

A response acting through a sensory nerve and a motor nerve in the central nervous system (CNS)

Question 20

Autonomic nervous system

Answer 20

Governs involuntary body functions

Question 21

Do sympathetic and parasympathetic nerves have opposite or equal reactions?

Answer 21

Opposite

Question 22

Sensory pathways have four functions in common

Answer 22

1) Reception
2) Transduction
3) Transmission
4) Perception

Question 23

Reception

Answer 23

Sensory receptors interact directly with stimuli, both inside and outside the body

Question 24

Sensory transduction (transduction)

Answer 24

The conversion of stimulus energy into receptor potential

Question 25

Receptor potential

Answer 25

A change in the membrane potential of a sensory receptor

Question 26

What does it mean that receptor potentials are “graded” potentials?

Answer 26

Their magnitude varies with the strength of the stimulus

Question 27

What occurs after energy has been transduced into a receptior potential?

Answer 27

Some sensory cells generate the transmission of action potentials to the central nervous system (CNS)

Question 28

Are all action potentials equal signals?

Answer 28

Yes

Question 29

What is encoded by the frequency of action potentials?

Answer 29

Information about the strength of the sensory stimulation

Question 30

Perceptions

Answer 30

The presentations of stimuli constructed in the brain

Question 31

How does the brain distinguish stimuli from different receptors?

Answer 31

The area of the brain where the action potential arrives tells the brain this information

Question 32

What can affect perception?

Answer 32

The amplification of and the adaptation to stimuli from receptors