VII- Intro Sensory Phys

Question 1

peripheral somatosensation contributes to

Answer 1

1. smooth and accurate movements
2. prevent minimization of injury
3. our understanding of external world

Question 2

where perception of sensation occurs

Answer 2

1. thalamus
2. cerebral cortex

Question 3

neuron pathways

Answer 3

1. order brings from receptors to spinal cord
2. order from spinal cord or brainstem to thalamus
3. order sends info from thalamus to cerebral cortex

Question 4

mechanoreceptors respond to

Answer 4

mechanical deformation by touch, pressure, stretch, vibration

Question 5

chemoreceptors respond to

Answer 5

locally released substances, damaged cells after injury/infection

Question 6

touch on skin conveyed by

Answer 6

light touch/vibrations/skin stretch/pressure by A-beta afferents

Question 7

nociception on skin conveyed by

Answer 7

A-beta and C afferents

Question 8

meissner’s corpuscle conveys

Answer 8

1. light touch
2. skin motion/detecting slipping objects

Question 9

pacinian corpuscle conveys

Answer 9

vibration cues transmitted by holding an object

Question 10

ruffini’s ending conveys

Answer 10

skin stretch

Question 11

merkel disk conveys

Answer 11

pressure

Question 12

hair follicle nerve endings convey

Answer 12

hair displacement

Question 13

free nerve endings convey

Answer 13

tissue threat or damage

Question 14

type I axons carrying musculoskeletal sensory signals

Answer 14

Ia and Ib
-are large diameter and myelinated
-Ia = muscle spindles (stretch)
-Ib = golgi tendon organs (tension)

Question 15

type II axons

M/S

Answer 15

A-beta
-medium diameter + myelinated
-muscle spindles act by stretch

Question 16

type III axons

M/S

Answer 16

A-delta
small diameter + myelinated
-innervate free nerve endings act by noxious stim

Question 17

type IV axons

M/S

Answer 17

C fibers
small diameter + unmyelinated
-inn free nerve endings act by noxious stim

Question 18

muscle length innervation

Answer 18

signaled by type Ia and II afferents
-adjusted by static gamma motor neurons efferents

Question 19

control of muscle velocity

Answer 19

velocity of change in muscle length signaled by type Ia afferents from nuclear bag fibers
-adjusted by dynamic gamma motor neurons efferents

Question 20

golgi tendon organs

Answer 20

to communicate tenion in tendons to CNS via type Ib afferents
-encapsulated nerve endings woven b/t collage strands
-respond to both contraction and stretch

Question 21

joint receptors

Answer 21

1. ligament: type Ib signal tension like golgi tendon
2. ruffini’s: type II signal extremes of joint range
3. free nerve endings: type III and IV singal noxious and inflamm

Question 22

ascending pathways

Answer 22

1. dorsal column for discrim touch and conscious proprioception, stereognosis
2. anterolateral column for pain, temp, crude touch

Question 23

DCML pathway

Answer 23

1. receptors in periphery to medulla ipsilateral via spinal dorsal column
2. medulla to thalamus VPL via medial lemniscus after crossing midline
3. thalamus to somatosensory cortex via internal capsule

Question 24

doral column parts

Answer 24

1. nucleus gracilis for lower limb and trunk
2. nucleus cuneatus for upper limb + upper trunk + neck