PSYC 101 > Chapter 3 pt.1 > Flashcards

Chapter 3 pt.1 Flashcards

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1
Q

What are neurons?

A

Cells in the nervous system that communicate with one another to perform information-processing tasks.

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2
Q

What are the three main parts of a neuron?

A

Cell body (soma), dendrites, and axon.

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3
Q

What does the cell body do?

A

It coordinates information-processing tasks and keeps the cell alive.

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4
Q

What important structures are inside the soma?

A

The nucleus (with DNA) and other organelles for protein synthesis and energy production.

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5
Q

What surrounds the soma?

A

A porous cell membrane that controls molecule flow in and out of the cell.

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6
Q

What is the function of dendrites?

A

They receive information from other neurons and relay it to the cell body.

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7
Q

What does the axon do?

A

Carries information to other neurons, muscles, or glands.

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8
Q

How long can an axon be?

A

Up to a meter long—from the spinal cord to the big toe!

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9
Q

What covers the axon?

A

A myelin sheath (an insulating layer of fatty material).

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10
Q

What is the myelin sheath made of?

A

Glial cells.

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11
Q

What is the myelin sheath function?

A

It insulates axons and helps transmit information more efficiently.

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12
Q

What are the three main roles of glial cells?

A

Digest parts of dead neurons.

Provide physical and nutritional support.

Form myelin to insulate neurons.

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13
Q

What are the types of glial cells

A

astrocytes
microglia
olgiodendrocytes
shwann cells

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14
Q

What do astrocytes do?

A

Regulate blood flow and the concentration of nutrients, ions, and neurotransmitters.

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15
Q

What do microglia do?

A

Remove debris.

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16
Q

What do oligodendrocytes and Schwann cells do?

A

Wrap axons with myelin, insulating them and speeding up signal conduction.

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17
Q

where are oligodendrocytes and Schwann cells found

A

Oligodendrocytes: CNS (brain and spinal cord).

Schwann cells: PNS (outside brain and spinal cord).

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18
Q

What is a synapse?

A

The junction between the axon of one neuron and the dendrite or cell body of another.

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19
Q

How is synapse information transmitted?

A

From the presynaptic neuron to the postsynaptic neuron.

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20
Q

Name the three parts of a synapse.

A

Presynaptic membrane: Axon of the transmitting neuron.

Synaptic cleft: The gap between neurons.

Postsynaptic membrane: Dendrite or cell body of the receiving neuron.

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21
Q

what are the three major types of neurons

A

sensory, motor, interneurons

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22
Q

What do sensory neurons do?

A

Receive information from the external world and send it to the brain via the spinal cord.

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23
Q

What kinds of signals do sensory neurons detect?

A

Light, sound, touch, taste, and smell.

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24
Q

What do motor neurons do?

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A

Carry signals from the spinal cord to muscles to produce movement.

25
What is special about motor in their structure?
They often have long axons that reach distant muscles.
26
What do interneurons do?
Connect sensory neurons, motor neurons, or other interneurons.
27
Where are most interneurons found?
In the brain and spinal cord.
28
What two types of signals do neurons use to communicate?
Electrical and chemical signals.
29
What happens first and second in neural communication?
1. An electrical signal travels within the neuron (dendrites → cell body → axon) 2. A chemical signal is sent between neurons across a synapse.
30
What allows ions to move in and out of a neuron?
Small pores (ion channels) in the cell membrane.
31
What does this ion movement create in the neuron
Electrical current within the neuron.
32
What is the resting potential of a neuron?
About -70 mV.
33
Which ions are more abundant inside the neuron?
Potassium (K⁺) and negatively charged proteins.
34
Which ions are more abundant outside the neuron?
Sodium (Na⁺), calcium (Ca²⁺), and chloride (Cl⁻).
35
Why do ion concentrations differ inside and outside the neuron?
Special membrane channels restrict ion movement.
36
What is the result of this difference of ion concentration?
The inside of the neuron is slightly negative relative to the outside.
37
What are local potentials?
Small changes in membrane potential.
38
What happens during depolarization?
The membrane becomes more positive (excitatory).
39
What happens during hyperpolarization?
The membrane becomes more negative (inhibitory).
40
What is an action potential?
An electrical signal conducted along the axon to the synapse.
41
What can trigger an action potential?
Enough depolarizing potentials adding up to reach threshold.
42
What is depolarization?
When the charge of the neuron shifts from -70 mV to a more positive value.
43
When does an action potential occur?
Only when stimulation reaches threshold.
44
What does “all-or-none” mean?
Action potentials either happen fully or not at all—never partial.
45
What helps prevent current leakage during conduction?
The myelin sheath (acts like insulation).
46
What causes the start of an action potential?
Sodium channels open when threshold is reached, and Na⁺ rushes in.
47
What happens to the charge inside the cell when an action potential starts?
It quickly rises from -70 mV to +40 mV.
48
How does the action potential move along the axon?
Sodium influx in one region triggers depolarization in the next—like falling dominos.
49
Why can’t the action potential move backward?
Sodium channels temporarily inactivate after firing.
50
What is the refractory period?
The time after an action potential when a new one can’t start.
51
What happens electrically during refractory period?
Sodium channels close; potassium channels open, allowing K⁺ to exit—returning negativity.
52
What happens chemically during refractory period?
Ion pumps (like the Na⁺/K⁺ pump) restore ion balance by moving Na⁺ out and K⁺ in.
53
When can the neuron fire again after refractory period?
After ion concentrations reset and resting potential is restored.
54
How are action potentials transmitted along the axon?
They are regenerated at each point along the axon.
55
Why do action potentials only travel in one direction?
Because the membrane behind is refractory (temporarily inactive).
56
What are the Nodes of Ranvier?
Gaps between myelinated sections of an axon.
57
How does current move between nodes of ranvier?
It “jumps” quickly from node to node.
58
What is this process of jumping between nodes called?
Saltatory conduction (makes transmission much faster).
PSYC 101
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