Ch 48-49 Nervous System Flashcards Preview

BIOL 172 > Ch 48-49 Nervous System > Flashcards

Flashcards in Ch 48-49 Nervous System Deck (32):
1

Neurons

Nerve cells

2

Where do neurons receive signals?

Their dendrites

3

What structure do signals received by neurons travel down?

The axon

This allows for rapid communication

4

Afferent nerves (sensory nerves)

Carry signals to the brain or central nervous system

5

Efferent nerves (motor nerves)

Carry signals out from the central nervous system

6

Resting membrane potential (-70 mV)

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

7

Action potential

An electrical signal that moves along the axon

8

What causes depolarization?

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

9

Depolarization

A change in the direction of the membrane potential

10

What does depolarization trigger?

Repolarization

11

Repolarization

Potassium ion movement out of the neuron

12

What does repolarization trigger?

Depolarization of the adjacent region

13

Why is an action potential considered an "all or nothing" response?

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

14

Synapses

Transmit action potentials between nerve cells

15

Neurotransmitters

Communicate transmission across synapses (electrical or chemical)

16

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

The opening of ion channels on the next nerve

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

17

Central nervous system (CNS)

Possessed by bilateral animals

18

The central nervous system (CNS) communicates with what?

A peripheral nervous system (PNS)

19

Reflex arc

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

20

Autonomic nervous system

Governs involuntary body functions

21

Do sympathetic and parasympathetic nerves have opposite or equal reactions?

Opposite

22

Sensory pathways have four functions in common

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

23

Reception

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

24

Sensory transduction (transduction)

The conversion of stimulus energy into receptor potential

25

Receptor potential

A change in the membrane potential of a sensory receptor

26

What does it mean that receptor potentials are "graded" potentials?

Their magnitude varies with the strength of the stimulus

27

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

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

28

Are all action potentials equal signals?

Yes

29

What is encoded by the frequency of action potentials?

Information about the strength of the sensory stimulation

30

Perceptions

The presentations of stimuli constructed in the brain

31

How does the brain distinguish stimuli from different receptors?

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

32

What can affect perception?

The amplification of and the adaptation to stimuli from receptors