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Neuroanatomy > Unit 1: S-S systems pgs 17-45 > Flashcards

Unit 1: S-S systems pgs 17-45 Flashcards

1
Q

Anatomically: Precuneus
Functionally: ?

A

S-S Association Cortex

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2
Q

Anatomically: Superior Parietal Lobule
Functionally: ?

A

S-S Association Cortex

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3
Q

Define sterognosis:

A

3-D knowledge

recognition/identification of an object held in the hand with eyes closed

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4
Q

What is Graphestheia

A

Traced figure ID

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5
Q

Anatomically: post-central gyrus
Functionally: ?

A

1˚ S-S Cortex

Specifically: Face, Upper extremity, Trunk

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6
Q

What is the 1˚ S-S Cortex comprised of?

A

Face
Upper extremity
Trunk
Lower extremity and perineum/pelvis

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7
Q

Anatomically: posterior paracentral lobule
Functionally: ?

A

1˚ S-S Cortex

Specifically: Lower extremity and perineum/pelvis

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8
Q

Two main pathways for somatosensory systems:

A

Spinothalamic tract = anterolateral system

Medial lemniscus system = dorsal/posterior column system

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9
Q

What tract monitors nociceptors, temperature, light/non-discriminative touch

A

Spinothalamic tract = anterolateral system

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10
Q

What is Agnosia

A

Without knowledge

‘A’ without
‘Gnosia’ knowledge

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11
Q

What is tactile agnosia

A

Inability to appreciate tactile info — cannot do 2-point discrimination, texture

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12
Q

What is agraphesthesia

A

Inability to recognize traced pattern on skin

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13
Q

What is Astereognosis

A

Inability to recognize an object held in the hand — size, shape, weight, etc

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14
Q

What system monitors: fine/discriminative touch, proprioception info and vibration

A

Medial lemniscus system = dorsal/posterior column system

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15
Q

What receptors are: unencapsulated free nerve endings, group Adelta (type III) fibers and group C (type IV) fibers, and monitors noxious stimuli (mechanical, thermal or chemical)?

A

Nociceptors

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16
Q

What receptors are ambiguous, include free nerve endings, group Adelta (type III), group C (type IV) fibers, monitor cool and warm temps (non-noxious range)

A

Temperature receptors

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17
Q

What receptors include unencapsulated and encapsulated nerve endings, group Adelta (type III), group Abeta (type II) fibers, and monitor tactile info?

A

Crude touch receptors

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18
Q

What is the kind of pain that is immediate, sharp, well-localized? Aka discriminate pain perception

A

Fast pain (nociceptors)

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19
Q

What is pain that is slower onset, dull, diffuse? Aka non-discriminate pain perception

A

Slow pain (nociceptors)

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20
Q

What is an important interneuron that is able to modify nociception pathways?

A

Lamina II - substantia gelatinosa

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21
Q

terminals of axons that lie next to cells or free in the extracellular space

A

unencapsulated endings

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22
Q

Which receptors have unencapsulated endings?

A
  • free nerve endings
  • Merkel discs/endings
  • peritrichial nerve endings
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23
Q

terminals of axons enclosed by a capsule of non-neuronal cells

A

encapsulated endings

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24
Q

Which receptors have encapsulated endings?

A
  • Pacinian corpuscles
  • Meissners corpuscles
  • Ruffini corpuscles/
    endings
  • End bulbs (of Krause, Golgi-Mazzoni, etc.)
  • neuromuscular spindles
  • neurotendinous spindles
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25
Q

axon terminals that are located between cells in many tissues

A

free nerve endings

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26
Q

Axon terminals associated with special cells that are located in deep layers of the epidermis and primarily found in glabrous skin

A

Merkel discs/endings

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27
Q

axon terminals that are distributed along the root of a hair follicle

A

peritrichial nerve endings

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28
Q

single axon terminal with layers of

non-neuronal cells

A

Pacinian corpuscles

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29
Q

highly branched axon inside a capsule that is long and slender

A

Meissners corpuscles

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30
Q

single axon inside delicate

capsule

A

Ruffini corpuscles/ endings

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31
Q 
Axon of variable sizes
and shapes
•  often round/ circular
•  contain single highly-branched axon
•  often found at muco-cutaneous junctions
A

End bulbs (of Krause, Golgi-Mazzoni, etc.)

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32
Q

axons located in skeletal muscle

A

neuromuscular spindles

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33
Q

Axons located in tendons, ligaments

A

neurotendinous spindles

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34
Q

Receptors in cutaneous areas

A
  • free nerve endings
  • peritrichial endings
  • Merkel discs/endings
  • Ruffini endings
  • Meissners corpuscles
  • pacinian corpuscles
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35
Q

Where will you find free nerve endings in the cutaneous areas?

A

found in (deep) epidermis, dermis, subcutaneous tissue and monitor thermal, noxious and tactile stimuli

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36
Q

Where will you find peritrichial endings in the cutaneous areas?

A

monitor movement of hair (tactile)

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37
Q

Where will you find Merkel discs/endings in the cutaneous areas?

A

found in deep layers of epidermis (tactile)

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38
Q

Where will you find Ruffini endings in the cutaneous areas?

A

found in dermis, subcutaneous tissue (tactile - especially stretch)

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39
Q

Where will you find Meissners corpuscles in the cutaneous areas?

A

found in dermal papillae of mainly glabrous (= hairless) skin; especially fingertips • tactile receptor

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40
Q

Where will you find pacinian corpuscles in the cutaneous areas?

A

found in dermis, subcutaneous tissue (act as mechanoreceptors, esp. for vibration)

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41
Q

Receptors in joints have what kind of nerve endings?

A
  • free nerve endings
  • small pacinian corpuscles
  • Ruffini-like endings
  • neurotendinous spindles (Golgi tendon organs)
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42
Q

What kind of receptor nerve endings are found in skeletal muscles?

A
  • free nerve endings

- neuromuscular spindles

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43
Q

Where in joints would you find free nerve endings?

A

in synovial membrane, joint capsule and periarticular CT

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44
Q

Where in joints would you find small pacinian corpuscles?

A

in periarticular CT around the joint capsule

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45
Q

WHere in joints would you find Ruffini-like endings?

A

in joint capsular tissue

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46
Q

Where in joints would you find neurotendinous spindles (Golgi tendon organs)?

A

in articular ligaments

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47
Q

Where in skeletal muscle would you find free nerve endings?

A

mainly associated with connective tissue

around muscle tissue

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48
Q

Where in skeletal muscles would you find meuromuscular spindles?

A

distributed mostly in muscle near its junction with tendon and most numerous in muscles that perform highly skilled maneuvers (e.g., hand)

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49
Q

What kind of receptors would you find in tendons?

A
  • free nerve endings

- Golgi tendon organs (GTOs)

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50
Q

What kind of receptors would you find in the viscera?

A
  • free nerve endings

- pacinian corpuscles

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51
Q

The pathway for sensory modalities of discriminative touch, vibration (not exclusive), and proprioception (although the pathway for proprioception is a bit different and will be described separately)

A

Medial Lemniscus System aka Dorsal/Posterior Column System

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52
Q

Qualities of discriminative touch include

A
  • recognize precise location of a tactile stimulus
  • 2-point discrimination - permits recognition of different textures
  • graphesthesia- identify a familiar pattern when traced on skin
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53
Q

Qualities of proprioception include:

A
  • information regarding the precise position of a body part (without visual aid), and the range and direction of movement (kinesthesia)
  • also permits one to appreciate the shape, size and weight of objects (held in the hand)
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54
Q

Qualities of vibration include:

A

sensation of an oscillating mechanical stimulus elicited by a tuning fork (128 Hz) set in motion and placed on the body

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55
Q

Primary neurons for the medial lemniscus system are located where?

A

Dorsal root ganglia

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56
Q

The central processes of primary neurons for the medial lemniscus system enter the ipsilateral ________ and branches into________ and _______ collaterals

A

dorsal funiculus
ascending
descending

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57
Q

Short ascending and descending collaterals from the central processes of primary neurons for the Medial Lemniscus System synapse _________ and modify __________.

A
  • spinal cord gray matter

- cord mediated activity - i.e., reflexes, sensory and motor activity

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58
Q

Long ascending collaterals from the central processes of primary neurons for fine touch and vibration for the body in the Medial Lemniscus System that enter cord below T6, project through the ipsilateral _______ to synapse in the nucleus gracilis on the ________ surface of the medulla

A
  • fasciculus gracilis

- dorsal/ posterior

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59
Q

In the Medial Lemniscus System (fine touch and vibration for body), fibers that enter the cord above T6 project through the ipsilateral _________ to synapse in the__________ on the dorsal/ posterior surface of the__________.

A

fasciculus cuneatus
nucleus cuneatus
medulla

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60
Q

Nucleus gracilis and cuneatus are located where?

A

Medulla

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61
Q

Nucleus gracilis and cuneatus receive information that originated from where?

A

The ipsilateral lower body and upper body respectively

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62
Q

Fibers for fine touch and vibration of the medial lemniscus tract do what after synapsing on secondary neuron cell bodies in nucleus cuneatus and nucleus gracilis?

A

They decussate and form a fiber tract called the medial lemniscus that ascends on the contralateral side of the brain stem

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63
Q

The secondary fibers of medial lemniscus tract ascend through the medulla, pons and midbrain to synapse on tertiary neurons (Except for lower body proprioception which have quaternary neurons) in the ________ of the thalamus

A

ventral posterior lateral (VPL) nucleus

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64
Q

Long ascending collaterals from the central processes of primary neurons for upper body proprioception in the Medial Lemniscus System that enter cord above T6, ascend through the ipsilateral _______ to synapse in the nucelus _______ on the ________ surface of the medulla

A

Fasciculus cuneatus
Cuneatus
Posterior

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65
Q

Long ascending collaterals from the central processes of primary neurons for lower body proprioception in the Medial Lemniscus System that enter cord below T6, ascend through the ipsilateral _______ to synapse in the nucelus _______.

A
  • Fasciculus gracilis

- Dorsalis (AKA Clarke’s nucleus)

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66
Q

Clarke’s nucleus is located where in the spinal cord grey matter? At what cord segment levels?

A
  • in Lamina VII of the spinal cord gray matter

- in cord segments C8-L3

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67
Q

Secondary neurons of Clarke’s nucleus project axons that ascend as the ipsilateral _______ into the medulla

A

dorsal spino-cerebellar tract

68
Q

Once in the medulla, axon collaterals of secondary neurons that came from Clarke’s nucleus will do one of two things. What are they?

A
  • go to the cerebellum via the inferior cerebellar peduncle

- synapse on (tertiary) neurons of the nucleus Z

69
Q

The secondary axons that go to the cerebellum via the inferior cerebellar peduncle are part of the__________ proprioception pathway.

A

unconscious

70
Q

The secondary axons that synapse on (tertiary) neurons of the nucleus Z are part of the__________ proprioception pathway.

A

Conscious

71
Q

Nuclei in the medulla that receive proprioceptive input are _______ for the upper body and ______ for the lower body. These neurons project axons ventrally & across midline into the
__________.

A
  • nucleus cuneatus for the upper body and nucleus Z for the lower body
  • contralateral medial lemniscus
72
Q

Fibers of the medial lemniscus are somatotopically arranged and ascend through the medulla, pons and midbrain to synapse on neurons of the _________ of the thalamus

A

ventral posterior lateral (VPL) nucleus

73
Q

Neurons of the VPL nucleus of the thalamus send axons through the ________. The fibers synapse in the ______ and the _______ of the parietal lobe.

A
  • posterior limb of the internal capsule

- post-central gyrus and posterior paracentral lobule

74
Q

Cutaneous innervation to the posterior 1/3 of the head and part of the external ear is provided by branches of ________.

A

C2 (C3) spinal nerves

75
Q

Most cutaneous innervation to the anterior 2/3 of the head is supplied by branches of ________.

A

Trigeminal (CN V)

NOTE: some parts supplied by VII, IX, X

76
Q

What are the three trigeminal sensory nuclei that extend through the brainstem and comprise the central pathway of the trigeminal system?

A
  • mesenphalic nucleus
  • pontine nucleus (AKA chief/principle sensory nucleus of trigeminal nerve)
  • spinal trigeminal nucleus (AKA spinal nucleus of trigeminal nerve)
77
Q

Cell bodies for primary neurons that provide fine touch and vibration innervation on the face are located in the _______

A

trigeminal sensory ganglion (aka Gasserian ganglion)

78
Q

Peripheral processes of primary neurons for fine touch and vibration in the trigeminal system are distributed with the ophthalmic, maxillary or mandibular divisions of the V nerve to supply peripheral receptors while central processes enter the pons with the V nerve and synapse in the __________.

A

pontine trigeminal nucleus

79
Q

Peripheral processes of primary neurons for proprioception in the trigeminal system are distributed in peripheral tissues (muscles of mastication, TMJ) then enter brainstem with V nerve, while central processes synapse on neurons in the __________.

A

pontine trigeminal nucleus

or other nearby nuclear areas - parts of reticular formation

80
Q

Secondary neuron cell bodies in pontine trigeminal nucleus (and reticular formation areas) send axons to the_________ side of brainstem to join the ___________.

A
  • contralateral

- trigeminothalamic tract (T-T tract)

81
Q

fibers of the trigeminothalamic (T-T) tract ascend through the brainstem and synapse on tertiary neurons in the ________ of the thalamus

A

ventral posterior medial

nucleus (VPM)

82
Q

tertiary neurons in the VPM nucleus of the thalamus send axons through the _________.

A

posterior limb of the internal capsule

83
Q

Fibers of the trigeminal system, which are carrying somatosensory information from the anterior 2/3 of the face, synapse in what area of the primary somatosensory cortex?

A

inferior lateral part of the post-central gyrus (near the lateral sulcus)

84
Q

What is the function of the Somatosensory Cortex of Parietal Lobe? What area/landmarks on the brain does it include?

A
  • it if the first cortical area that receives, processes, integrates, and interprets ALL somatosensory data from the thalamus for subjective assessment
  • post-central gyrus and posterior part of the paracentral lobule
85
Q

specific body parts are mapped or represented on different areas of the post-central gyrus &
posterior paracentral lobule. What is this organization called?

A

Somatotopic

86
Q

Somatosensation for one side of the body is represented on which half of the cerebrum?

A

Contralateral

87
Q

The somatotopic organization of the ‘face’ area on the primary somatosensory cortex is ________.

A

inferior lateral part of the post-central gyrus near the lateral sulcus

88
Q

The somatotopic organization of the upper extremity area on the primary somatosensory cortex is ________.

A

interomedial-lateral location along the post central gyrus

89
Q

The somatotopic organization of the trunk area on the primary somatosensory cortex is ________.

A

Superior lateral part of the post central gyrus

90
Q

The somatotopic organization of the proximal lower extremity area on the primary somatosensory cortex is ________.

A

Superior most part of the post central gyrus

91
Q

The somatotopic organization of the distal lower extremity and perineum area on the primary somatosensory cortex is ________.

A

Posterior part of the paracentral gyrus

92
Q

What does sensory homunculus mean?

A

Sensory “miniature human”

93
Q

What is the relationship between cortical surface area for a body part and the sensitivity of the body part?

A

The relationship is reciprocal

Increased cortical surface area for the body part = increased sensitivity for the body part

94
Q

General functions of primary somatosensory cortex include:

A
  • general awareness of somatosensory data
  • localization of a stimulus
  • appreciation of qualities of a stimulus
95
Q

Where in the brain is the secondary somatosensory cortex located?

A

inferior to the postcentral gyrus, in the superior wall of the lateral sulcus (extending onto insula)

96
Q

What is the function of the secondary somatosensory cortex?

A

less discriminative aspects of general somatosensation

97
Q

Where in the brain is the somatosensory association cortex located?

A

includes parts of the parietal lobe:

- much of the superior parietal lobule (on lateral surface) - precuneus (on the medial surface)

98
Q

The primary somatosensory cortex corresponds to which Brodmann map areas?

A

3,2,1

99
Q

The somatosensory association cortex corresponds to which Brodmann map areas?

A

5,7

100
Q

The somatosensory association cortex receives input from where?

A
  • primary somatosensory cortex
  • areas of the thalamus
  • other cortical areas including visual cortex
101
Q

The somatosensory association cortex functions to integrate somatosensory data - complex assessment of data that permits:

A

▪ recognition of patterns of data
▪ appreciation of the significance of all s-s data
▪ associating current experience with previous experience

102
Q

What is the ability to identify an object without visual data, using size, shape, weight, and texture details (i.e. proprioceptive and tactile data)?

A

Stereognosis

103
Q

What is the ability to identify a familiar pattern that is traced on an area of skin (with eyes closed)?

A

Graphesthesia

104
Q

What are some clinical tests for the integrity of the medial lemniscus system?

A

All done with patient’s eyes closed:
a. limb/joint position recognition: a body
part is passively moved
b. two-point discrimination: the ability to resolve two points vs. one point of tactile stimulation
c. graphesthesia: familiar figure is traced on skin
d. stereognosis: touch and handle object to use size, shape, weight, fine touch, and texture info to ID object
e. vibration: 128 htz tuning fork placed on DIP of finger

105
Q

What is a disruption of a pathway anywhere along its length by trauma, tumors, vascular problems, or other causes?

A

Lesion

106
Q

What is agnosia? What are some examples of it?

A

“negative knowledge”; lack of appreciation of the significance of sensory information
Examples:
- tactile agnosia = lack of appreciation of the significance of tactile info
- agraphesthesia = inability to recognize pattern of a moving stimulus on the skin
- astereognosis = inability to recognize an object held in the hand without looking at it

107
Q

What is the pathway for sensory modalities of nociception, temperature, crude touch (and pressure)?

A

Spinothalamic System (AKA Anterolateral System)

108
Q

What is the function of the spinothalamic tract?

A

permits for recognition of the source, severity and quality of noxious and thermal stimuli and provides for appropriate emotional/autonomic responses to such stimuli

109
Q

How do sensations of nociception and temperature serve to protect an individual?

A

they warn us of stimuli that can potentially cause injury

110
Q

What at the receptors that monitor noxious mechanical or thermal stimuli, or noxious chemicals released from damaged cells? Are their nerve endings encapsulated or unencapsulated?

A
  • noxious stimuli receptors AKA nociceptors

- unencapsulated (‘free’)

111
Q

Are the nerve endings for thermal receptors encapsulated or unencapsulated?

A

unencapsulated (‘free’)

112
Q

Are the nerve endings for crude touch receptors encapsulated or unencapsulated?

A

Both: unencapsulated nerve endings (peritrichial, Merkel, free nerve endings) and some encapsulated endings

113
Q

_________ and _________ monitor pressure on the skin (tactile sensation) and are supplied by Group _____ fibers

A
  • Ruffini endings and pacinian corpuscles

- A beta

114
Q

A noxious stimulus can activate a series of events in the nervous system that results in:

A
  • reflex (motor) response, known as a “flexor- reflex”

- perception of noxious stimuli

115
Q

Perception of noxious stimuli occurs in two stages:

A
  • ‘fast pain’ (nociception) = discriminate pain perception:

- ‘slow pain’ (nociception) = non-discriminate pain perception

116
Q

What kind of fibers are the collateral, peripheral and central process of the primary neurons for the pathway for Fine Touch & Vibration for the body (except face) in the medial lemniscus system?

A

A beta fibers

117
Q

What kind of fibers are the collateral, peripheral and central process of the primary neurons for the pathway for proprioception for the body (except face) in the medial lemniscus system?

A

A alpha, A beta fibers

118
Q

What kind of fibers are the processes of the primary neurons that provide fine touch and vibration innervation on the face?

A

A beta

119
Q

What kind of fibers are the processes of the primary neurons that provide proprioception innervation on the face?

A

A alpha and A beta

120
Q

Peripheral nerve fibers associated with nociceptors and temperature receptors are made of what kind of fibers?

A

A delta and C

120
Q

What is the pathway for Nociception, Temperature and Crude Touch for the Body (not face)?

A

Spinothalamic Tract (Anterolateral System)

120
Q

Where are the primary neuron cell bodies for the spinothalamic tract located?

A

DRG above T6 for upper body and DRG below T6 for lower body

121
Q

What kind of fibers are associated with nociception and temperature in the spinothalamic system?

A

A delta and C

121
Q

What kind of fibers are associated with crude touch in the spinothalamic system?

A

A beta and A delta

121
Q

What kind of fibers are associated with nociception, crude touch and temperature in the trigeminal system?

A

A delta and C

121
Q

What kind of fibers are associated with fine touch and vibration in the trigeminal system?

A

A beta

122
Q

What kind of fibers are associated with proprioception in the trigeminal system?

A

A alpha and A beta

123
Q

What kind of fibers are associated with fine touch and vibration in the medial lemniscus system?

A

A beta

124
Q

What kind of fibers are associated with proprioception in the medial lemniscus system?

A

A alpha and A beta

125
Q

Where are the primary neurons of the spinothalamic system located?

A

DRG below T6 for lower body and DRG above T6 for upper body

126
Q

Central processes of the primary neurons in the spinal thalamic system enter the spinal cord through the _______ and then enter the ipsilateral ________ and branch into ascending and descending collaterals.

A
  • Dorsal root zone

- dorsolateral tract (AKA Lissauer’s tract)

127
Q

When does sensory information for nociception and temperature in the spinothalamic system influence motor neurons for reflex response?

A

After they have synapsed with secondary neurons in the dorsal horn of spinal gray matter.

128
Q

Secondary neurons of the spinothalamic tract are located primarily in which lamina of the dorsal horn gray matter?

A

ipsilateral laminae IV, V and VI

Some in lamina I

129
Q

When and how do the axons of second order neurons in the spinothalamic system deccusate?

A

They deccusate via the anterior white commisure and then ascend in the contralateral anterolateral/ spinothalamic tract

130
Q

As the fibers of the spinothalamic system ascend the cord, they are joined by additional crossing fibers along what edge of the tract? this results in a pathway that has what?

A
  • along the medial edge of the tract

- somatotopic organization

131
Q

Fibers of the spinothalamic tract ascend through the brainstem and synapse on tertiary neuron cell bodies in the ________ of the thalamus.

A

ventral posterior lateral (VPL) nucleus

132
Q

Axons of third order neurons in the spinothalamic system project through the _______ to the ________ (if from the lower body) and to the _______ (if from the upper body)

A
  • posterior limb of the internal capsule
  • posterior part of the paracentral lobule
  • post-central gyrus
133
Q

The lateral spinothalamic tract appears to be responsible for which stage of pain perception?

A

the ‘fast’ stage of pain perception

134
Q

Not all spinothalamic tract fibers synapse in the VPL nucleus of the thalamus, therefore the anterolateral system includes more than the lateral spinothalamic tract. What are the alternate pathways collectively know as?

A

medial (projecting) spinothalamic tract (AKA paleospinothalamic tract).

135
Q

The medial spinothalamic tract includes _______ fibers that synapse in the brain stem and somatosensory fibers that synapse in other nuclei of the thalamus (not the VPL), including:

A
  • spinoreticular
  • the intralaminar nuclei
  • posterior nuclei
  • mediodorsal nuclei
136
Q

The diffuse network of nuclei in the brainstem that have direct and indirect connections with virtually all levels of the central nervous system including many areas of the cerebral cortex and influences many activities (i.e., sleep cycles, nociception/sensory, perception, movement, visceral activity, consciousness, etc.)?

A

reticular formation

137
Q

The alternative projections of the medial spinothalamic tract ultimately provide for:

A

sensations of nociception to influence areas of the cerebral cortex that influence emotions and behavior (limbic areas), sensory perception and levels of consciousness.

138
Q

What stage of pain perception does the medial spinothalamic tract appears to provide?

A

the ‘slow’ stage of pain perception

139
Q

What accounts for why ‘non-discriminate’ pain sensation is still perceived following destruction of the primary somatosensory cortex?

A

medial spinothalamic tract

140
Q

Cell bodies for primary neurons that provide crude touch, nociception and temperature innervation on the face are located in the _______

A

Trigeminal (aka Gasserian) ganglion

141
Q

Central processes of primary neurons for crude touch, temperate and nociception in the trigeminal system, enter which part of the brainstem with cranial nerve 5? They descend in the brainstem via what tract?

A
  • pons

- spinal trigeminal tract

142
Q

Where do primary neuron fibers for crude touch of the face synapse in the trigeminal system?

A

On secondary neuron cell bodies in pars rostralis of

the spinal trigeminal nucleus

143
Q

Where do primary neuron fibers for nociception and temperature of the face synapse in the trigeminal system?

A

Secondary neuron cell bodies in pars caudalis of the spinal trigeminal nucleus

144
Q

The cell bodies of the spinal trigeminal nucleus (pars rostralis and caudalis) project axons to the contralateral side of which part of the
brainstem? What tract do they ascend to the thalamus in?

A
  • medulla
  • (ventral) trigeminal thalamic tract

note: some fibers remain uncrossed and ascend to the thalamus in the ipsilateral trigeminothalamic tract

145
Q

The fibers of the trigeminothalamic tract ascend the brainstem and synapse on tertiary neurons in the _____ of the thalamus.

A

ventral posterior medial (VPM) nucleus

146
Q

The tertiary neurons in the VPM nucleus project axons through what structure?

A

the posterior limb of the internal capsule

147
Q

What is the functional significance of projections to the primary somatosensory cortex from the trigeminal system?

A

permits conscious perception and awareness of discriminative nociception, temperature, crude touch, fine touch, vibration and proprioception

148
Q

Neurons in alternative pathways of nociception from the face activate pathways that provide what stage of pain perception?

A

“slow’ stage of the pain perception

149
Q

Alternative pathways of nociception from the face

Include projections to:

A
  • brainstem reticular formation
  • posterior nuclei of the thalamus
  • intralaminar nuclei of the thalamus
  • mediodorsal nuclei of the thalamus
  • wide areas of the cerebral cortex
150
Q

What are some examples of clinical tests used to check the integrity of the Anterolateral System?

A
  • pin-prick test for nociception
  • test tubes of warm or cool water for temperature
  • wisp of cotton for crude touch
151
Q

What is parasthesia?

A

abnormal sensation

152
Q

What is anesthesia?

A

loss of all somatosensation

153
Q

What is analgesia?

A

absence of pain perception in response to a typically noxious stimulus

154
Q

What affect on the spinothalamic system can mechanical compression (such as from IVD herniation or inflammation) of peripheral nerve fibers have?

A

stimulate nociceptive and temperature fibers causing paresthesia

155
Q

A degenerative condition characterized by cavitation of the central part of the spinal cord?

A

syringomyelia

156
Q

Where does syringomyelia most often occur and how far can the lesion extend?

A

cervical enlargement of cord: lesion can extend from CX to TX cord segments

157
Q

What are the early symptoms of Syringomyelia?

A

loss of nociceptive and temperature sensations (analgesia for bilateral upper extremity)

158
Q

What are the late symptoms of Syringomyelia as the lesion progresses into the ventral horn?

A

motor loss

159
Q

A loss of blood supply to the lateral medulla causing an infarct that disturbs many structures of the brainstem including the spinothalamic tract, spinal trigeminal nucleus and spinal trigeminal tract is called what?

A

lateral medullary syndrome (aka Wallenberg’s syndrome)

160
Q

What would the somatosensory impairments of lateral medullary syndrome (aka Wallenberg’s syndrome) be?

A

▪ loss of nociception and temperature sensation of the contralateral body
▪ loss of nociception and temperature sensation of ipsilateral face

163
Q

Peripheral nerve fibers associated with receptors for crude touch are made of what kind of fibers?

A

A beta and A delta

Neuroanatomy (21 decks)

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