Section 6 Flashcards

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1
Q

What is the definition for nervous tissue, and what role does it play in conjunction with the endocrine system?

A
  • tissue specialized for rapid transmission of signals from cell to cell
  • works along with the endocrine system to coordinate homeostasis and body activities
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2
Q

What are the two types of nervous systems?

A

Central nervous system and peripheral nervous system

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3
Q

What components make up the central nervous system?

A

The brain and the spinal cord

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4
Q

What parts make up the peripheral nervous system

A
  1. Somatic Nervous System
  2. Autonomic Nervous System
    — sympathetic
    — parasympathetic
  3. Enteric Nervous System
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5
Q

What is a neuron?

A

Nerve cell

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6
Q

What are the 3main parts of a neuron?

A

Cell body
Dendrites
Axon

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7
Q

Where is the nucleus located (generally) within a neuron?

A

Centrally

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8
Q

Cell bodies contain what two parts?

A

Nissl bodies and rough endoplasmic reticulum

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9
Q

What is the functions of dendrites?

A

The long extensions receive signals and then transmit them to the nucleus

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10
Q

What is the difference between axon signals and dendritic signals

A

Axons send signals across or to the synapse of a nerve while dendrites send signals to the nucleus in the cell body

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11
Q

What is the region where the axon joins the cell body

A

Axon hillock

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12
Q

What are the names for the cytoplasm and cell membrane of an axon

A

Axoplasm and axolemma

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13
Q

What is an axon collateral?

A

Branches that come off the axon

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14
Q

What is the synaptic end bulb and what is typically found in this structure?

A

The end of the axon that contacts the synapse
Typically houses vesicles that contain neurotransmitters

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15
Q

What is the region where the axon communicates with the end organ?

A

The synapse

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16
Q

What are the two types of axonal transport systems?

A

Fast axonal transport and slow axonal transport

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17
Q

In what direction does fast axonal transport move material?

A

Moves material along the axon in both directions via synaptic vesicles

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18
Q

In what direction does slow axonal transport move materials? What material is it moving?

A

This mechanism transports axoplasm from the cell body toward the synapse

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19
Q

What is a myelin sheath and what is the name of the region that is located below it?

A

A lipid/protein coating that surrounds the axons of certain neurons and the region called the Node of Ranvier is located below it

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20
Q

Where are multipolar neurons found and what is the ratio of dendrites to axons?

A

Many dendrites to one axon
Found in the brain and spinal cord

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21
Q

Where are bipolar neurons typically found and what is the axon and dendrite ratio?

A

Typically found in the eyes and ears and has one axon and one dendrite

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22
Q

What type of neurons are unipolar neurons associated with?

A

Sensory neurons

23
Q

What are neuroglia or glial cells good for?

A

They support the function of the nervous system

24
Q

What are the 6 types of neuroglia cells?

A

Astrocytes, oligodendrocytes, microglia, ependymal cells, Schwann cells, Satellite cells

25
Q

What are the only neuroglia cells that aren’t in the CNS

A

Schwann cells and Satellite cells

26
Q

What is resting membrane potential? (RMP)

A

The electrical potential across the axon membrane that is produced by the different ions located on each side of the membrane

Outside is positive (sodium and chloride ions)
Inside is negative (potassium, phosphates, amino acids)

27
Q

What are voltage gated channels and where are they located?

A

Channels that open and close in response to changes in voltage. Located in the axolemma of neurons

28
Q

What are sodium potassium pumps and what do they do?

A

Located in the axolemma, they help control ion leakage across the axon membrane

29
Q

What happens when voltages gated Na+ channels open in response to a stimulus, the membrane voltage becomes more positive as the positive ions rush inside the membrane.

This originates at the axon hillock**

A

Depolarization

30
Q

What is repolarization?

A

The restoration of resting membrane potential

31
Q

What is action potential? What drives it?

A

The electrical signal that is sent down the axon. It is driven by depolarization and repolarization.

32
Q

What is an electrical stimulus that is strong enough to initiate an action potential called?

A

Threshold stimulus

33
Q

What is the generalized idea behind the All-or-none principle?

A

The initial stimulus has to reach threshold before an action potential is generated.

34
Q

What happens in the events associated with an action potential?

A
  1. Threshold stimulus is reached
  2. Voltage gated channels open (depolarization)
  3. Repolarization
  4. Hyperpolarization (membrane voltage is below RMP)
  5. RMP is restored by sodium potassium pumps
35
Q

What is a refractory period?

A

The time in which an excitatory cell cannot generate another action potential

36
Q

What does the absolute refractory period measure?

A

The period of time from activation of voltage gated sodium channels until they reach a resting state

37
Q

During hyperpolarization a ___________ than a normal threshold stimulus is needed to activated an action potential.

A) larger
B) smaller
C) none of the above

A

A) larger

38
Q

What kind of conduction describes the propagation of a nerve impulse in a step by step depo and repo of adjacent areas of the axolemma

A

Continuous conduction

39
Q

What kind of conduction happens when an action potential is passing from one Node of Ranvier to the next until the impulse reaches the synapse?

A

Saltatory conduction

40
Q

What kind of conduction is associated with myelinated neurons?

A

Saltatory conduction

41
Q

What kind of conduction is associated with unmyelinated neurons?

A

Continuous conduction

42
Q

In general, what are the steps associated with chemical synapses?

A

A nerve impulse stimulates a vesicles to release a neurotransmitter into the cleft

The transmitter diffuses across the cleft and interacts with a specific receptor (on the post synaptic neuron)

The post synaptic neuron generates a graded potential that is transmitted to the axon hillock

43
Q

What does excitatory postsymaptic potential do to the threshold stimulus?

A

Adds to the threshold stimulus by making the dendrite more positive

44
Q

Inhibitory postsynaptic potential does what to the threshold stimulus?

A

Takes away from the threshold stimulus and causes hyperpolarization (negative ions flow in, positive ions flow out)

45
Q

What prevents continuous stimulation of postsynaptic neurons?

A

Deactivation or removal of neurotransmitters from the synaptic cleft

46
Q

What are 3 types of deactivation of neurotransmitters?

A
  1. Diffusion from the synaptic cleft
  2. Enzymes breaking down transmitters
  3. Uptake by cells
47
Q

What are 3 types of deactivation of neurotransmitters?

A
  1. Diffusion from the synaptic cleft
  2. Enzymes breaking down transmitters
  3. Uptake by cells
48
Q

What is summation?

A

Integration of the excitatory or inhibitory postsynaptic potential until a threshold stimulus is reached

49
Q

What is the main difference in spacial summation and temporal summation?

A

Spacial sum is caused by SEVERAL bulbs releasing neurotransmitters to build up graded potentials while temporal is a one to one in rapid succession

50
Q

What disease is acytocholine linked to?

A

Alzheimer’s (rapid degradation of ACh releasing neurons in the brain)

51
Q

Which amino acids are excitatory?

A

Glutamate and Aspartate

52
Q

Which amino acids are inhibitory?

A

Gamma Aminobutyric Acid (GABA) and glycine

53
Q

What are biogenic amines and what are 3 examples?

A

Modified amino acids

Dopamine (Parkinson’s)
Serotonin (SSRI)
Epinephrine (also norepinephrine)

54
Q

What are the early and later effects of axon repair in the peripheral nervous system?

A

Early:
Cell body swells
Wallerian degeneration occurs
Proximal portion of the axon degree rates to the nearest Node of Ranvier
Nissel bodies become granular in appearance
Later effects:
Schwann cells undergo mitosis to form regeneration tube across the injury site
Axon reconstruction begins gradually within the sheath
Scar tissue in the tube will stop regeneration
Function is restored