Viscerosomatic Sensation/Somatosensory Pathways Flashcards Preview

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

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

A

Trigeminal sensory neurons (CNV)

Trigeminal (semilunar) ganglion

2
Q

Encapsulated terminal of DRG neurons are responsible for ____

A

sensations of touch and proprioception

3
Q

Bare nerve endings of DRG neurons are responsible for ____

A

Thermal and painful sensations

4
Q

4 elementary attributes of stimuli

A

Modality
Location
Intensity
Duration

5
Q

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

A

Muscles
Proprioceptors of skeletal msucles
Fastest transduction

6
Q

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

A

Group II
Mechanoreceptors of skin
Discriminative touch

7
Q

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

A

Group III

Cool, sharp pain

8
Q

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

A

Group IV
Warm and cool, aching pain, itch
Slowest

9
Q
Meissner's corpuscle
Fiber group:
Modality:
Adaption speed:
Location
A

A beta
Stroking, fluttering
Fast
Superficial skin

10
Q
Merkel's disk receptor
Fiber group:
Modality:
Adaption speed:
Location:
A

A beta
Pressure
Slow
Superficial skin

11
Q
Pacinian corpuscle
Fiber group:
Modality:
Adaption speed:
Location:
A

A beta
Vibration
Fast
Deep subcutaneous tissue

12
Q
Ruffinin ending
Fiber group:
Modality:
Adaption speed:
Location:
A

A beta
Skin stretch
Slow
Deep subcutaneous tissue

13
Q

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

A
Fast, fast
Changes in muscle length
Alpha motor nuerons 
Deep tendon reflex
Increasing muscle tension
14
Q

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

A

Type II fibers

15
Q

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

A

Type Ib fibers

Inhibit

16
Q

Thermal nociceptors
Activated by:
Fibers used:

A

Extreme temperature

Alpha delta

17
Q

Mechanical nociceptors
Activated by:
Fibers used:

A

Intensive pressure applied to skin

Alpha delta

18
Q

Polymodal nociceptors
Activated by:
Fibers used:

A

High intensity chemical, mechanical or thermal stimuli

Nonmyelinated C fibers

19
Q

Visceral afferent nerves
Cell bodies located:
Majority of fibers:

A

DRG or CN ganglia

Alpha delta and C fibers (slow conducting)

20
Q

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

A
thickly myelinated fibers 
Large encapsulated somatic receptors
Muscle spindles (Ia)
Golgi tendon organs (Ib)
Pacinian corpuscles (Abeta)
Meissner's corpuscles (Abeta)
21
Q

Golgi tendon organs (GTOs)

A

Signal tendon tension

22
Q

Diminshed or absent deep tendon reflex indicates lesion that affects ____

A

Afferent or efferent neurons for that specific spinal cord segment

23
Q

Exaggerated deep tendon reflex indicates lesion that affects ____

A

Upper motor neuron (disrupted inhibition on LMN)

24
Q

Golgi tendon reflex involves:

A

Ib afferent, 1 or 2 interneurons

25
Q

Dorsal column system transmits:

A

Tactile sensation
Conscious proprioception
Kinesthesia

26
Q

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

A

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

27
Q

Dorsal column system

_____ cable together more medially, _____ more laterally

A

Sacral fibers

Cervical fibers

28
Q

Dorsal column system

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

A

Lower medulla

Nucleus gracilis and nucleus cuneatus

29
Q

Medial lemniscus

A

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

30
Q

Location of neuron 3 in dorsal column system: ____

Fibers ultimately end in _____

A

Ventral posterolateral nucleus in that thalamus

Limb and trunk areas of primary somatosensory cortex in postcentral gyrus

31
Q

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

A

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

32
Q

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

A

Contralateral (b/c it has already crossed in the medulla)

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

33
Q

Romberg’s test

A

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
Q

Spinothalamic system runs in ____ and ____

A

Anterior (ventral) and lateral funiculi

35
Q

Spinothalamic system

Ascending 2nd order fibers mostly cross in _____

A

Spinal cord

36
Q

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

A

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

37
Q

Lissauer’s tract

A

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

38
Q

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

A

Laminae 1, 4, 5, 6

Ventral (anterior) white commissure

39
Q

Spinothalamic system

_____ cable together more medially, _____ more laterally

A

Cervical

Sacral

40
Q

Spinothalamic tract fibers end in _____

A

Ventral postlateral nucleus and other thalamic nuclei

41
Q

Spinothalamic system

Locations of neuron 2

A

Posteromarginal nucleus
Substantia gelatinosa
Nucleus proprius

42
Q

Lesion of anterior white commissure results in ___

A

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
Q

Visceral pain pathway

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

A

Gracile fasciculi, lesser exten in cuneate fasciculi

Do NOT cross

44
Q

3 pathways of spinocerebellar pathways

A

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

45
Q

Location of neuron 2 of dorsal spinocerebellar tract

A

Dorsal nucleus of Clarke

46
Q

Dorsal nucleus of Clarke is part of ____ pathway

A

Dorsal spinocerebellar tract

47
Q

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

A

Do not
Ipsilateral
Inferior cerebellar peduncle

48
Q

Dorsal nucleus of Clarke exits in ______

A

Thoracic/upper lumbar cord

49
Q

Dorsal spinocerebellar tract conveys information from _____

A

Only trunk and lower limb

50
Q

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

A

dorsal column

51
Q

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

A

Fasciculus cuneatus
Medulla
Accessory cuneate nucleus

52
Q

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

A

Cuneocerebellar tract
Ipsilateral cerebellum
Inferior cerebellar peduncle

53
Q

Venral spinocerebellar tract conveys ____

A

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

54
Q

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

A

Ventral spinocerebellar tract

55
Q

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 ____.

A
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
Q

3 systems of trigeminal sensory complex

A

Spinal tract and nucleus
Main sensory nucleus
Mensencephalic nucleus

57
Q

Spinal tract and nucleus functions:

A

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

58
Q

Main sensory nucleus

A

Discriminative touch sensation from head and face

Like DCML system w/o conscious proprioception

59
Q

Mesencephalic nucleus

A

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

60
Q

Location of main sensory nucleus

A

Pons, adjacent and lateral to motor nucleus of V

61
Q

Mesencephalic nucleus contains ____ that end up in the ____

A

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

62
Q

Neurons of the mesencephalic nucleus communicate by _____

A

electrical gap junctions

63
Q

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

A

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

64
Q

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

A

Motor nucleus of V (MoV)

Jaw-jerk reflex

65
Q

Jaw-jerk reflex is exaggerated in ____

___ signs resulting from damage to ____ inputs to ____

A

Corticobulbar lesions

UMN, corticobulbar inputs, MoV

66
Q

Ventral trigeminothalamic tract (VTT) formed from:

A

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

67
Q

VTT terminates in ____

A

Ventral posteromedial (VPM) nucleus of thalamus

68
Q

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

A

medial

Spinothalamic tract

69
Q

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

A

medial leminiscus

70
Q

Trigeminal lemniscus formed from

A

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

71
Q

Dorsal trigemino-thalamic tract (DTT) formed from

A

Ascending uncrossed main sensory nucleus