Viscerosomatic Sensation/Somatosensory Pathways Flashcards Preview

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Flashcards in Viscerosomatic Sensation/Somatosensory Pathways Deck (71):
1

Somatosensory information from most cranial structures is transmitted by ____, with cell bodies located in ____.

Trigeminal sensory neurons (CNV)
Trigeminal (semilunar) ganglion

2

Encapsulated terminal of DRG neurons are responsible for ____

sensations of touch and proprioception

3

Bare nerve endings of DRG neurons are responsible for ____

Thermal and painful sensations

4

4 elementary attributes of stimuli

Modality
Location
Intensity
Duration

5

Group 1 axons
Originate from:
Sensory receptors:
Speed of transduction:

Muscles
Proprioceptors of skeletal msucles
Fastest transduction

6

Axon from skin: A-beta axons
Axons from muscles: Group ___
Sensory receptors:
Responsible for:

Group II
Mechanoreceptors of skin
Discriminative touch

7

Axon from skin and viscera: A-delta axons
Axons from muscles: Group ___
Responsible for:

Group III
Cool, sharp pain

8

Axons from skin: C axons
Axons from msucles: Group ___
Responsible for:
Speed of transduction:

Group IV
Warm and cool, aching pain, itch
Slowest

9

Meissner's corpuscle
Fiber group:
Modality:
Adaption speed:
Location

A beta
Stroking, fluttering
Fast
Superficial skin

10

Merkel's disk receptor
Fiber group:
Modality:
Adaption speed:
Location:

A beta
Pressure
Slow
Superficial skin

11

Pacinian corpuscle
Fiber group:
Modality:
Adaption speed:
Location:

A beta
Vibration
Fast
Deep subcutaneous tissue

12

Ruffinin ending
Fiber group:
Modality:
Adaption speed:
Location:

A beta
Skin stretch
Slow
Deep subcutaneous tissue

13

____-conducting Type Ia fibers are ___-adapting. Respond to ____. They excite ____ during the ___ reflex, which causes ___.

Fast, fast
Changes in muscle length
Alpha motor nuerons
Deep tendon reflex
Increasing muscle tension

14

Type of muscle fiber active during steady state after a change in muscle length.

Type II fibers

15

Fast-conducting fibers that respond to stretch on tendon, which ____ alpha motor neurons.

Type Ib fibers
Inhibit

16

Thermal nociceptors
Activated by:
Fibers used:

Extreme temperature
Alpha delta

17

Mechanical nociceptors
Activated by:
Fibers used:

Intensive pressure applied to skin
Alpha delta

18

Polymodal nociceptors
Activated by:
Fibers used:

High intensity chemical, mechanical or thermal stimuli
Nonmyelinated C fibers

19

Visceral afferent nerves
Cell bodies located:
Majority of fibers:

DRG or CN ganglia
Alpha delta and C fibers (slow conducting)

20

Dorsal root fibers enter spinal cord through medial bundle contain _____ which convey impulses from _______. Ex: ____

thickly myelinated fibers
Large encapsulated somatic receptors
Muscle spindles (Ia)
Golgi tendon organs (Ib)
Pacinian corpuscles (Abeta)
Meissner's corpuscles (Abeta)

21

Golgi tendon organs (GTOs)

Signal tendon tension

22

Diminshed or absent deep tendon reflex indicates lesion that affects ____

Afferent or efferent neurons for that specific spinal cord segment

23

Exaggerated deep tendon reflex indicates lesion that affects ____

Upper motor neuron (disrupted inhibition on LMN)

24

Golgi tendon reflex involves:

Ib afferent, 1 or 2 interneurons

25

Dorsal column system transmits:

Tactile sensation
Conscious proprioception
Kinesthesia

26

Dorsal column system's spinal cord components are _____ which is made up of ____ and ____. Composed of ____.

The dorsal columns
Gracile and cuneate fasciculi
Heavily myelinated axons of DRG fibers

27

Dorsal column system
_____ cable together more medially, _____ more laterally

Sacral fibers
Cervical fibers

28

Dorsal column system
Gracile and cuneate fasciculi ascend to the ____ and synapse on the ___ and ___.

Lower medulla
Nucleus gracilis and nucleus cuneatus

29

Medial lemniscus

Formed from decussated second-order neurons in gracile/cuneate nuclei in medulla
Location of neuron 2 in dorsal column system

30

Location of neuron 3 in dorsal column system: ____
Fibers ultimately end in _____

Ventral posterolateral nucleus in that thalamus

Limb and trunk areas of primary somatosensory cortex in postcentral gyrus

31

Lesion of dorsal column result in (ipsilateral or contralateral) loss of ______ (4) in body segments ____ the level of the lesion

Ipsilateral
Conscious proprioception, kinesthesia, 2-point discrimination, vibration sense
Below

32

Lesion of the medial lemniscus result in (ipsilateral or contralateral) loss of ______ (4)

Contralateral (b/c it has already crossed in the medulla)
Conscious proprioception, kinesthesia, 2-point discrimination, vibration sense

33

Romberg's test

Test of DCML dysfunction. Relies on fact that w/o visual clues, balance requires conscious proprioception. Lose awareness of proprioception when eyes are closed.

34

Spinothalamic system runs in ____ and ____

Anterior (ventral) and lateral funiculi

35

Spinothalamic system
Ascending 2nd order fibers mostly cross in _____

Spinal cord

36

Lesions of spinothalamic tract result in loss of ____ on ____ side of body ____ the level of lesion

Pain and temperature
Contralateral
Below, 1-2 segments below level of lesion (Lissauer's tract)

37

Lissauer's tract

Some A beta and C fibers of spinothalamic system ascend spinal cord in this tract before entering dorsal horn and synapse.

38

Spinothalamic tract neurons (2nd order) are mostly found in _____. Their axons cross in ____.

Laminae 1, 4, 5, 6
Ventral (anterior) white commissure

39

Spinothalamic system
_____ cable together more medially, _____ more laterally

Cervical
Sacral

40

Spinothalamic tract fibers end in _____

Ventral postlateral nucleus and other thalamic nuclei

41

Spinothalamic system
Locations of neuron 2

Posteromarginal nucleus
Substantia gelatinosa
Nucleus proprius

42

Lesion of anterior white commissure results in ___

bilateral segmental loss of pain and temperature, 1-2 segments below the level of the lesion.
Will still have sensation above and below the lesion

43

Visceral pain pathway
2nd order neurons run in _____ to reach higher centers. They (do/do not) cross

Gracile fasciculi, lesser exten in cuneate fasciculi
Do NOT cross

44

3 pathways of spinocerebellar pathways

Dorsal (posterior) spinocerebellar tract: lower extremities
Cuneocerebellar tract: upper extremities
Ventral (anterior) spinocerebellar tract: whole limb position and kinesthesia

45

Location of neuron 2 of dorsal spinocerebellar tract

Dorsal nucleus of Clarke

46

Dorsal nucleus of Clarke is part of ____ pathway

Dorsal spinocerebellar tract

47

Dorsal spinocerebellar tract axons (do/do not) cross the spinal cord to enter (contralateral/ipsilateral) ____ via the _____

Do not
Ipsilateral
Inferior cerebellar peduncle

48

Dorsal nucleus of Clarke exits in ______

Thoracic/upper lumbar cord

49

Dorsal spinocerebellar tract conveys information from _____

Only trunk and lower limb

50

Neuron 1 of the dorsal spinocerebellar tract enters the spinal cord through ____

dorsal column

51

Neuron 1 of the cuneocerebellar tract enters the spinal cord through ____ and ascends to the ___ to synapse on ____

Fasciculus cuneatus
Medulla
Accessory cuneate nucleus

52

2nd order fibers of the cuneocerebellar tract form ____ at the accessory cuneate nucleus to enter the (contralateral/ipsilateral) ___ via the ___.

Cuneocerebellar tract
Ipsilateral cerebellum
Inferior cerebellar peduncle

53

Venral spinocerebellar tract conveys ____

Nonconscious proprioceptive information about movement and posture of whole (lower) limb

54

Which pathway has its neurons cross twice to end up on the same side?

Ventral spinocerebellar tract

55

2nd order fibers of the ventral spinocerebellar tract are located at _____ at ____ levels. They cross in the ____ and ascend in the _____ to the ____ where they ____ to enter the _____ via the ____.

The base lateral to dorsal gray horn
Lumbosacral levels
ventral white commissure
Anterolateral white matter
upper pons
cross the midline again
cerebellum
superior cerebellar peduncle

56

3 systems of trigeminal sensory complex

Spinal tract and nucleus
Main sensory nucleus
Mensencephalic nucleus

57

Spinal tract and nucleus functions:

Pain, temp, crude touch from face, head, nasal and oral cavities
Like spinothalamic tract of spinal system

58

Main sensory nucleus

Discriminative touch sensation from head and face
Like DCML system w/o conscious proprioception

59

Mesencephalic nucleus

All conscious and nonconscious proprioception from mm. of mastication, periodontal ligament, facial and tongue muscles

60

Location of main sensory nucleus

Pons, adjacent and lateral to motor nucleus of V

61

Mesencephalic nucleus contains ____ that end up in the ____

primary afferent neurons
Midbrain
*only structure in CNS to contain primary afferent cell bodies

62

Neurons of the mesencephalic nucleus communicate by _____

electrical gap junctions

63

Mesencephalic nucleus sends axons to the ____, located between the ___ and ___.
This transmits _____ about _____

Supra-trigeminal nucleus (S-TN)
Motor nucleus and main sensory nucleus
Conscious proprioception
Jaw and tongue position

64

Major output target of mesencephalic nucleus is the ____ for participation in ____

Motor nucleus of V (MoV)
Jaw-jerk reflex

65

Jaw-jerk reflex is exaggerated in ____
___ signs resulting from damage to ____ inputs to ____

Corticobulbar lesions
UMN, corticobulbar inputs, MoV

66

Ventral trigeminothalamic tract (VTT) formed from:

2n order fibers of spinal nucleus, main sensory nucleus, supra-trigeminal nucleus

67

VTT terminates in ____

Ventral posteromedial (VPM) nucleus of thalamus

68

VTT fibers from spinal nucleus run alongside ___ aspect of the ____

medial
Spinothalamic tract

69

VTT fibers from main sensory nucleus and supra-trigeminal nucleus run alongside the ____

medial leminiscus

70

Trigeminal lemniscus formed from

VTT (ventral trigemino-thalamic tract) and DTT (dorsal trigemino-thalamic tract)

71

Dorsal trigemino-thalamic tract (DTT) formed from

Ascending uncrossed main sensory nucleus