Sensory Systems

Question 1

What is Somatosensory?

Answer 1

Bodily sensations of touch, pain, temperature, vibrations and proprioception

-received from sensory receptors in skin and muscle

Question 2

What are the 5 cutaneous mechanorecptors

Answer 2

Free Nerve endings
Messiner Corpuscles
Merkel Cells
Ruffini Endings
Pacinian Corpuscles

Question 3

What do the free nerve endings do and what is their receptor field?

Answer 3

Temperature, pain and crude touch
-most superficial

Small or large receptors fields

Question 4

What do the Meissner corpuscles and what are their receptor fields

Answer 4

Light touch

Small receptor fields

Question 5

What do the Merkel Cells and what are their receptor fields

Answer 5

Light touch

Small receptor fields

Question 6

What do the Ruffini Endings and what are their receptor fields

Answer 6

Vibration, pressure
Stretching of skin - help provide secondary info re: proprioception

Large receptor fields

Question 7

What do the Pacinian Corpuscles and what are their receptor fields

Answer 7

Vibration, Pressure
Large Receptor fields

Most Deep

Question 8

What is proprioception

Answer 8

Sense of joint/limb position in space

Question 9

What are the 3 proprioceptors?

Answer 9

Muscle Spindles
Golgi Tendon Organs
Joint Receptors

Question 10

What do Muscle spindles of the proprioceptors do and where are they located?

Answer 10

Rate and degree of stretch

Intrafusal fibers: run parallel to muscle fibers

Question 11

What do Golgi Tendon Organs of the proprioceptors do and where are they located?

Answer 11

Monitor tension within tendons

Near muscle-tendon junction

Question 12

What do Joint Receptors of the proprioceptors do and where are they located?

Answer 12

Monitor stretch in synovial joints

Sends info to cerebellum and spinal reflex arcs

Question 13

What are the 3 joint receptors and do they help with?

Answer 13

Pacinian: AROM
Ruffini: indicate end range and PROM
Free Nerve Endings: pain from joint inflammation

Question 14

What are the 4 Sensory nerve fibers (in order from biggest to smallest)

Answer 14

A alpha
A beta
A delta
C

Question 15

What 2 qualities distinguish between the sensory nerve fibers?

Which nerve fiber has the least and the most

Answer 15

Primarily surrounding their diameter size and presence of myelin

C and A alpha

Question 16

What are dermatomes?

Answer 16

Area of skin with sensory innervation by the single dorsal spinal root

Question 17

What do the cutaneous peripheral nerves supply?

Answer 17

Area of the skin that related to a peripheral nerve

Question 18

What are the 3 segments of the Psuedounipolar neuron?

Answer 18

Distal Axon (PNS)
Dorsal Root Ganglion
Proximal Axon (CNS)

Question 19

What is in the Distal Axon?

Answer 19

Mechanoreceptors and proprioceptors
Dorsal (back) and Ventral (ventral trunk & limbs) Rami
Spinal Nerve

Question 20

What is in the Proximal Axon

Answer 20

Dorsal Root

Question 21

What does the dorsal column help with in regards to somatosensory

Answer 21

Light touch, proprioception, vibration

Question 22

What does the anterolateral column do in regards to somatosensory system?

Answer 22

Pain, temperature, pressure & crude touch

Question 23

What does the Medial Lemniscal Pathway convey?

Answer 23

Conveys proprioception, vibration and discriminative touch

Question 24

What do the Anterolateral pathways convey?

Answer 24

Pain, temperature, crude touch and pressure

Question 25

What are the 3 tracts of the anterolateral pathways and what are their general functions?

Answer 25

Spinothalamic: discrimination (location and intensity) of pain, temperature and crude touch

Spinoreticular: Emotional and arousal aspects of pain

Spinomesencephalic: Pain modulation

Question 26

What is the function of the Thalamus

Answer 26

Crucial relay station for all pathways traveling to the cortex (afferent)

Question 27

What are the 3 relay nuclei in the Thalamus

Answer 27

Medial Nuclear Group
Lateral Nucleus Group
Anterior Nuclear Group

Question 28

What is unique about thalami reticular nucleus

Answer 28

Do NOT project to cortex, instead receives info from the Reticular Formation

Helps with thalamic regulation

Question 29

Ventral Posterior Lateral (VPL) Nucelus of the Relay Nuclei of Lateral Nuclear Group
(Modality it receives and where is it going)

Answer 29

Somatosensory (Spinal cord) to primary sensory cortex

Question 30

Ventral posteromedial nucleus (VPM) of the Relay Nuclei of Lateral Nuclear Group
(Modality it receives and where is it going)

Answer 30

Somatosensory (CNs) to primary sensory cortex

Question 31

Lateral geniculate nucleus (LGN) of the Relay Nuclei of Lateral Nuclear Group
(Modality it receives and where is it going)

Answer 31

Vision to primary visual cortex

Question 32

Medial geniculate nucleus (MGN) of the Relay Nuclei of Lateral Nuclear Group
(Modality it receives and where is it going)

Answer 32

Auditory to primary auditory cortex

Question 33

Ventral Lateral (VL) Nucelus of the Relay Nuclei of Lateral Nuclear Group 
(Modality it receives and where is it going)

Answer 33

Cerebelllum and basal ganglia to primary motor cortex, premotor and supplementary motor cortex

Question 34

Ventral Anterior (VA) nucleus of the Relay Nuclei of Lateral Nuclear Group 
(Modality it receives and where is it going)

Answer 34

Cerebellum and basal ganglia to primary motor cortex, premotor and supplementary motor cortex, frontal lobe

Question 35

Mediodorsal (MD) Nucleus of the Relay Nuclei in the Medial Nuclear group
(Modality it receives and where is it going)

Answer 35

Limbic, basal ganglia to frontal cortex

Question 36

Anterior Nucleus of the Relay Nuclei in the Anterior Nuclear group
(Modality it receives and where is it going)

Answer 36

Mammillary body, hippocampus to cingulate gyrus