Nervous System Flashcards

1
Q

Information processing steps

A
  1. Sensory input
  2. Integration
  3. Motor output
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2
Q

Sensory neurons

A

Function in transmitting information from external stimuli

Afferent: bringing in info

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3
Q

Interneurons

A

Function in integration of sensory information

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4
Q

Motor neurons

A

Function in triggering muscle or gland activity

Efferent: sending out info

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5
Q

Central nervous system

A

Portion of nervous system where signal processing and integration takes place
Includes brain and nerve cord

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6
Q

Peripheral nervous system

A

Portion of nervous system that carries information in and out of the CNS

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7
Q

Nerves

A

Neurons of PNS bundled together
Information transfer
Afferent (signals into CNS) and efferent (signals out of CNS)

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8
Q

Cell body (soma)

A

Location of most of neuron’s organelles

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9
Q

Dendrites

A

Highly branched extensions that receive signals from other neurons

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10
Q

Axon

A

Long extension that transmits signals to other cells at synapses

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11
Q

Axon hillock

A

Cone-shaped base of axon (place where axon is attached to cell body)

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12
Q

Synaptic terminal

A

End of axon

Passes information across the synapse

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13
Q

Neurotransmitters

A

Chemical messengers

Information that is transmitted across synapse

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14
Q

Synapse

A

Junction between an axon and another cell

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15
Q

Flow of information transfer

A

Info is transmitted from presynaptic cell (neuron) to postsynaptic cell (neuron, muscle, or gland cell)

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16
Q

Glial cells

A

Nourish or insulate neurons

17
Q

Membrane potential

A

Cell’s voltage difference across its membrane

Changes in this act as signals

18
Q

Resting potential definition

A

Membrane potential of a neuron not sending signals

19
Q

Resting potential of a mammalian neuron

A

K+ is highest inside cell
Na+ is highest outside cell
Many open K+ channels, but fewer open Na+ channels: K+ diffuses outside of cell (resulting buildup of negative charge is major source of membrane potential)

20
Q

Sodium-potassium pumps

A

Use energy of ATP to maintain K+ and Na+ gradients across plasma membrane (chemical potential energy)

21
Q

Opening of ion channels in plasma membrane

A

Conversion of chemical potential to electrical potential

22
Q

Gated ion channels

A

Open or close in response to stimuli, causing changes in membrane potential

23
Q

Hyperpolarization

A

Increase in magnitude of membrane potential (increase in negative charge)
Caused by opening of gated K+ channels: K+ diffuses out of cell, making inside of cell more negative

24
Q

Depolarization

A

Reduction in magnitude of membrane potential

Opening other types of ion channels (ex: Na+) counteracts hyperpolarization

25
Graded potential
Changes in polarization where the magnitude of the change varies with the strength of the stimulus
26
Action potential
Massive change in membrane voltage caused by a large shift in membrane potential by depolarization Constant magnitude, all-or-none, transmit signals over long distances
27
Voltage-gated ion channels
Open or close when the membrane potential passes a certain level
28
Action potential steps
1. Resting potential (voltage-gated Na+ and K+ channels are closed) 2. Voltage-gated Na+ channels open: Na+ flows into cell 3. Rising phase: threshold is crossed and membrane potential increases 4. Falling phase: voltage-gated Na+ channels become deactivated and voltage-gated K+ channels open, causing K+ to flow out of cell 5. Undershoot: membrane permeability to K+ is higher than normal, and then voltage-gated K+ channels close and resting potential is restored 6. Refractory period: second action potential cannot be initiated (temporary inactivation of Na+ channels)