Neuroanatomy Week 3 - PNS Flashcards

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1
Q

What do sensory receptors respond to?

A

pain, temperature, touch, and pressure.

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2
Q

Where are sensory receptors found?

A

throughout the whole body

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3
Q

What are sensory receptors?

A
  • transducers,
  • Stimulate chemical stimuli to create action potentials
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4
Q

What are the 2 categories of afferent neurons?

A
  1. Somatic
  2. Visceral

Afferent neurons

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5
Q

What are somatic afferent neurons associated with?

A

the skin, bones,
muscles,
and connective tissue

that makes up most of the
mass of the body (soma)

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6
Q

What are visceral afferent neurons associated with?

A

for the internal organs of the circulatory, respiratory, alimentary, excretory,
and reproductive systems.

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7
Q

Where are somatic efferent neurons (motor neurons) found?

A

ventral grayhorns of the spinal
cord

and motor nuclei of cranial nerves.

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8
Q

How are the fibers of peripheral nerves (except the very small ones)
arranged?

A

in bundles or fascicles

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9
Q

What is the entire PNS nerve is surrounded by?

A

epineurium

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10
Q

What do epineurial collagen fibres help with?

A

-stretching the nerve
- flexion of joints and movements

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11
Q

What is the perinerium?

A

The perineurium is a sheath that surrounds small bundle of fibers (fascile) in a nerve

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12
Q

What is another name for endoneurium?

A

Henle’s sheath or intrafascicular connective tissue

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13
Q

What is the endoneurium?

A

connective tissue sheath that directly surrounds individual Schwann cell–axon units

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14
Q

What is a neurolemma?

A
  • outermost layer of Schwann cells
  • surrounds the axon of the neuron.
  • thin sheath around a nerve fiber
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15
Q

The cytoplasm (axoplasm) of an axon contains what 4 organelles?

A
  • neurofilaments,
  • microtubules,
  • smooth endoplasmic reticulum,
  • mitochondria.
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16
Q

What is an axolemma?

A

Plasma membrane around the nerve cell is called axolemma

The axolemma is responsible for maintaining the membrane potential of the axon, and contains ion channels through which ions can flow rapidly.

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17
Q

What is an axoplasm?

A

Cytoplasms of an axon

18
Q

What is neurilemma?

A

Neurilemma is the plasma membrane of Schwann cells that surrounds the myelinated nerve fibers of PNS

19
Q

Define saltatory conduction

A

propagation of action potentials along myelinated axons from one node of Ranvier to the next

20
Q

The most rapidly conducting myelinated fibers in a nerve are ?

A

largest diameters and the longest internodes.

21
Q

Are there nodes of ranvier on unmyelinated neurons?

A

no

22
Q

What is an unmyelinated fibre surrounded by?

A

a single layer of the glial cell’s plasma membrane

23
Q

Do schwann cells cover unmyelinated neurons in the PNS?

A

Yes, only a single layer

They are not insulated

They may cover multiple axons at a time

24
Q

Where are unmyelinated neurons found?

A

Olfactory system
Enteric system
alimentary canals

25
Q

What superficial sensory receptors located
in the skin called?

A

exteroceptors

26
Q

What are 3 types of exteroceptors?

A
  • Chemoreceptors
  • Telereceptors
  • Cutaneous receptors
27
Q

What are chemoreceptors associated with?

A

Taste & smell

28
Q

What are cutaneous receptors associated with?

A
  • Pain
  • Touch
  • Pressure
  • Temperature
29
Q

What are telereceptors associated with?

A

Vision & hearing

30
Q

What are 2 types of interoreceptors?

A

Visceroreceptors
Proprioceptors

31
Q

What are 4 visceroreceptors and where are they found?

A
  1. Chemoreceptors
    (GI tract)
  2. Stretch receptors (intestines, bladder, heart)
  3. Baroreceptors
    (blood vessels)
  4. Osmoreceptors
    (Urinary tract, brain)
32
Q

What are visceroreceptors ?

A

Receptors found in the organs

33
Q

What are externoreceptors?

A

Found in the skin

34
Q

What are proprioreceptors associated with?

A

Joints and tendons

35
Q

Explain Encapsulated vs non-encapsulated nerve endings

A
36
Q

Free non-encapsulated nerve endings are associated with>

A

Free nerve endings

  • Found in epidermis, dermis and subcutaneous tissue
  • The terminal end (receptor) has no myelin
  • Detects pain, touch
    and pressure
37
Q

PNS – Encapsulated Sensory Endings

A
38
Q

Where is grey and white matter found in the spinal cord?

A

White matter is the peiperhy and grey matter is in the centre

39
Q

What are ventral horns associated with?

A

Motor neurons cell bodies that innervate skeletal muscles

40
Q

What are dorsal horns associated with?

A

Sensory neurons

Receive somatosensory information from the periphery

41
Q

What are dorsal horns associated with?

A

Sensory neurons

Receive somatosensory information from the periphery

42
Q

What are lateral horns associated with?

A

autonomic neurons that innovate visceral and pelvic organs