Somatosensory pathways and receptors (Dr. Duas)

Question 1

What are the two types of cutaneous receptors for conscious proprioception

Answer 1

rapidly adapting and the slowly adapting receptors

Question 2

function of rapidly adapting receptors

Answer 2

respond to application and removal of the stimulus but NOT during maintained stimulation

Question 3

function of slowly adapting receptors

Answer 3

active as long as the stimulus is present

Question 4

merkels disk senses

Answer 4

pressure

Question 5

paccinian corpuscle senses

Answer 5

vibration

Question 6

meissner’s corpuscle senses

Answer 6

tactile impulse

Question 7

ruffini’s endings sense

Answer 7

pressure

Question 8

pathway for conscious proprioception from the limbs and the trunk ?

Answer 8

PCMLS pathway

Question 9

Pathway for PCMLS pathway

Answer 9

Primary afferent
fasiculus cuneatus/fasciculus gracilis–>fasiculus cuneate nuclei within the medulla–>medial lemniscus–>VPL of thalamus

Question 10

fasciculus gracillis

Answer 10

sacral, lumbar and lower thoracic levels

Question 11

fasciculus cuneatus

Answer 11

upper thoracic and cervical levels

Question 12

in the alternative PCMLS pathway where do the synapses occur

Answer 12

lamina II and IV, as well as the typical cuneatus nuclei and gracillis nuclei

Question 13

what provides conscious proprioception from the head

Answer 13

anterior and posterior trigeminothalamic tracts

Question 14

describe the posterior trigeminothalamic tract

Answer 14

synapses in principal nucleus and ascends via the PTTT (does NOT cross the midline) to VPM

Question 15

describe the anterior tigeminothalamic tract

Answer 15

principal nucleus, crosses midline and ascends via ATT to VPM

Question 16

where is the primary central cortex located ?

Answer 16

post central gyrus

Question 17

if you have lesion in area 1 of the PSC what do you lose ?

Answer 17

loss of texture and discrimination

Question 18

if you have a lesion in area 2 of the PSC what do you lose ?

Answer 18

loss of size and shape discrimination

Question 19

what is asterogenesis

Answer 19

loss of size and shape

Question 20

if you have a lesion in area 3b of the PSC what do you lose?

Answer 20

diminished texture discrimination and asterogenesis (loss of size and shape)

Question 21

cutaneous receptors are found where in PSC

Answer 21

3b and 1

Question 22

proprioceptive receptors are found where in PSC

Answer 22

3a and 2

Question 23

where is the second somatosensory cortex found (SII)

Answer 23

inner face of the upper bank of the lateral sulcus

Question 24

the secondary somatosensory cortex is supplied by

Answer 24

middle cerebral artery

Question 25

lesion of the posterior spinal artery leads to injury to what

Answer 25

posterior columns (PCML pathway)

Question 26

lesion of the anterior spinal artery would injury what

Answer 26

medial lemniscus (PCML pathway)

Question 27

lesion of the thalamogeniculate branches of the posterior cerebral artery would result in injury to

Answer 27

VPL and VPM

Question 28

injury to the anterior and middle cerebral arteries would injury the

Answer 28

primary sensory cortex

Question 29

lesion to the basilar and superior cerebellar arteries would result in injury to

Answer 29

basilar and superior cerebellar arteries

Question 30

what are the two pathways for nonconscious proprioception ?

Answer 30

spinocerebellar pathway | trigeminocerebellar pathway

Question 31

spinocerebellar pathway functions to

Answer 31

sensory information from the limbs and the trunk

Question 32

trigeminocerebellar pathway functions to

Answer 32

sensory information from the head

Question 33

nonconscious proprioception to lower limb

Answer 33

anterior spinocerebellar tract | posterior spinocerebellar tract

Question 34

nonconsciocus proprioception to the upper limb

Answer 34

rostral spinocerebellar tract | cuneocerebellar tract

Question 35

which two spinocerebellar pathways are mostly mechanoreceptors

Answer 35

anterior spinocerebellar | rostral spinocerebellar

Question 36

what is friedrich ataxia

Answer 36

congenital autosomal recessive disease-degeneration of the spinal cord pathways including spinocerebellar tracts leading to lack of coordination during walking and other movements

Question 37

where do the primary afferent fibers synapse in the spinocerebellar tract

Answer 37

posterior tract-dorsal nucleus of clark (lamina 7-T1-L2) | anterior tract- lamina 5, 8, spinal border cells of L3-L5

Question 38

which part of the tracts for lower limb of the spinocerebellar tracts are mostly cutaneous mechanoreceptors

Answer 38

anterior spinocerebellar tract

Question 39

which tract of the spinocerebellar tracts cross the midliine

Answer 39

anterior spinocerebellar tract (anterior commissure)

Question 40

the spinocerebellar tracts enter the _________before they ascend into the lateral cerebellar vermis

Answer 40

restiform body (the rostral spinocerebellar tract also enters the cerebellar peduncle)

Question 41

where does the rostral spinocerebellar tract synapse before ascending up the spinal cord

Answer 41

lamina VII (C4-C8)

Question 42

Describe the Pathway of the cuneocerebellar tract ?

Answer 42

primary afferent fibers ascned via the cuneocerebellar tract and synapse in the lateral cuneate nucleus enter the restiform body and enter the medial cerebellar vermis (does not cross midline)

Question 43

describe the pathway of the rostral spinocerebellar tract ?

Answer 43

primary afferent fibers synapse in lamina VII to anterior spinocerebellar tract through restiform body and cerebellar peduncle to the LATERAL cerebellar vermis (does NOT cross the midline)

Question 44

what are the main pathways of protopathic sensibility

Answer 44

anterolateral system (spinothalamic and spinoreticular tract spinocerbicothalamic tract anterior trigeminothalamic tract

Question 45

A-delta mechanical nociceptors

Answer 45

thinly myelinated fibers

Question 46

C-polmodal nociceptors

Answer 46

nonmyelinated fibers

Question 47

describe the spinothalamic tract

Answer 47

primary afferent fibers synapse in lamina 1,5, and 2 cross at each segment at the anterior commissure ascend via ALS axon collaterals to the reticular formation VPL of the thalamus

Question 48

types of fibers in lamina 1 and 5

Answer 48

a delta fibers

Question 49

types of fibers in lamina 2

Answer 49

c fibes

Question 50

describe the spinoreticular tract

Answer 50

parimary afferent fibers in lamina II and III, interneurons 5, 8, cross at anterior commisure and ascend via anterolateral : spinoreticluar fibers and VPL of thalamus

Question 51

where does the spinocervicothalamic tract synapse

Answer 51

limain III, IV, acsends and then lateral cervical nucleus and then crosses midline

Question 52

protopathic for the head

Answer 52

ATT tract, synapses in spinal trigeminal nucleus and acsends via ATT and enters VPM

Question 53

what is wallenberg syndrome

Answer 53

lesion of the posterior inferior cerebellar artery resulting in CONTRALATERAL loss of pain, temperature and crude touch over the body and ipsilateral loss over the face

Question 54

rupture of arterila vasocorona between the ant. and post. spinal arteries would injur

Answer 54

spinal als

Question 55

posterior inferior cerebellar artery would injure

Answer 55

medullary ALS and spinal trigeminal nucleus

Question 56

injury to the thalamogeniculate branches of the posterior cerebral artery would injur

Answer 56

VPL and VPM

Question 57

injury to the anterior and middle cerebral arteries would injur

Answer 57

primary sensory cortex

Question 58

syringomyleIA

Answer 58

cystic cavitation of the central regions of the spinal gray matter; destruction of the decussating ALS fibers in the anterior commisure

Question 59

where is pain perceived

Answer 59

at the subcortical levels

Question 60

what pathway seems necessary to localize pain

Answer 60

spinothalamic pathway

Question 61

what pathway is important for suffering component of the pain experience (some drugs like benzodiazepines can disrupt this component)

Answer 61

spinoreticular

Question 62

VPL injury causes what type of pain

Answer 62

transient release of pain

Question 63

VPM injury causes what type of pain

Answer 63

long lasting pain relief

Question 64

function of enkephalingergic neruons

Answer 64

they suppress the activity of pain fibers