Lecture 2: Somatosensory System Pt 1: fine touch, vibration, proprioception

Question 1

what is an example of a neuron cell receptor

Answer 1

olfactory receptor neuron

Question 2

what is an example of a non-neuron receptor cell

Answer 2

hair cells
rods/cones
taste cells
merkel cells

Question 3

what are examples of nerve ending receptors

Answer 3

specialized capsules
free nerve ending

Question 4

what type of information do mechanoreceptors detect

Answer 4

touch, vibration, stretch

Question 5

what type of information do chemoreceptors detect

Answer 5

taste, smell, pH, O2

Question 6

what type of information do thermoreceptors detect

Answer 6

cold/hot
flavor of food

Question 7

what type of information do nociceptors detect

Answer 7

noxious stimuli
pain

Question 8

what type of information does free nerve endings detect

Answer 8

all functions of mechanoreceptors, chemoreceptors, thermoreceptors, nociceptor

Question 9

is somatotopy maintained with information gathered via special senses

Answer 9

yes

the senses are encoded in the same region (i.e. taste is in the tongue, smell through the nose, etc)

Question 10

where is conscious localization of stimuli projected to

is somatotopy maintained

Answer 10

primary sensory cortex

somatotopy is maintained

Question 11

where is unconscious localization of stimuli projected to

Answer 11

subcortical structures (RF and cerebellum)

Question 12

what determines the intensity and duration of a stimuli

Answer 12

the size and duration of the receptor potential

Question 13

ionotropic receptors are transduced via __

Answer 13

ligand/modality gated ion channels

Question 14

metabotropic receptors are transduced via __

Answer 14

G protein coupled receptors

Question 15

a quick pull/stretch of a muscle is an example of (slowly/rapidly) adapting

Answer 15

rapidly

Question 16

describe the location and function of meissner corpuscle

Answer 16

located on the border of epidermis and dermis

on hairless skin only

detects flutter/vibration

Question 17

describe the location and function of hair follicle receptors

Answer 17

on hair skin only

detects fine touch and movement

Question 18

describe the location and function of merkel cells

Answer 18

located at the border of dermis and epidermis

detects fine touch and perceiving edges

Question 19

describe Ruffini endings function

Answer 19

somatic

stretch sensation in skin

Question 20

what is the function and location of pacinian corpuscle

Answer 20

located throughout the entire body

detects vibration on the skin

Question 21

list all the cutaneous fine touch /vibration mechanoreceptors

Answer 21

meissner corpuscle
hair follicle receptors
merkel cells
ruffini endings
pacinian corpuscle

Question 22

what axons are located in the skin (cutaneous fine touch, vibration mechanoreceptors)

describe their characteristics

Answer 22

A-beta neuron axons

large diameter axons, myelinated, fast conduction

Question 23

where are meissner and merkel units located most in the body

Answer 23

finger tips and lips

Question 24

what are the 2 types of muscle fibers cells

describe each type

Answer 24

nuclear chain cells: nuclei aligned in a line

nuclear bag cells: nuclei concentrated as in a bag

Question 25

describe extrafusal muscle cells

Answer 25

alpha motor neuron comprise the bulk of the muscle form major force-generating structure

Question 26

describe intrafusal muscle cells

Answer 26

gamma motor neuron buried in the muscle contain afferent receptors for stretch

Question 27

what clinical test is used to test A-aplha specifically in the joint

Answer 27

tuning fork

Question 28

A-alpha fiber is responsible for detecting what sensations is it superficial or deep in the CNS

Answer 28

proprioception superficial

Question 29

A-beta fiber is responsible for detecting what sensations is it superficial or deep in the CNS

Answer 29

fine touch, vibraation deep

Question 30

if a patient presents with decreased fine touch sensations, what artery would you suspect is damaged or blocked

Answer 30

anterior spinal artery

Question 31

if a patient presents with decreased proprioception and vibration sensation, what artery would you suspect is damaged or blocked

Answer 31

posterior spinal artery

Question 32

what spinal level is fasciculus cuneatus located

Answer 32

above t6

Question 33

what spinal level is fasciculus gracilis located

Answer 33

below t6

Question 34

what information is carried via interfascicularis and septomarginal fasciculus

Answer 34

visceral and some somatic pain

Question 35

where is the second order neuron for the DCMLS pathway located

Answer 35

caudal medulla

Question 36

where does the fasciculus gracilis synapse

Answer 36

gracile nucleus

Question 37

where does the fasciculus cuneatus synapse

Answer 37

cunate nucleus

Question 38

where is the 3rd order neuron for the DCMLS

Answer 38

ventral posterolateral nucleus of thalamus

Question 39

is proprioception more superficial or deep

Answer 39

superficial

Question 40

what is the first order neuron in the trigeminothalamic pathway what information is relayed at this section

Answer 40

trigeminal ganglion fine touch, vibration, some proprioception

Question 41

what develops the mesencephalic nucleus

Answer 41

trigeminal ganglion

Question 42

the mesencephalic nucleus is the first order neuron for what sensations

Answer 42

proprioception of muscles, joints, periodontal ligaments

Question 43

where does the mesencephalic nucleus project to

Answer 43

motor nucleus for myotatic reflex and main sensory nucleus

Question 44

what cranial nerves follow the spinal trigeminal nucleus pathway

Answer 44

VII, IX, X

Question 45

what is the third order neuron for the trigeminothalamic pathway

Answer 45

ventral posteromedial nucleus (VPM)

Question 46

what information is located in the shell and core of the ventral posteromedial nucleus (VPM)

Answer 46

shell: proprioception core: vibration/fine touch

Question 47

where do the VPL and VPM project to is somatotopy maintained

Answer 47

S1 somatotopy is maintained