Somatosensory System I

Question 1

Exteroception

Answer 1

External stimuli

Touch, temperature, pain

Question 2

Function of mechanical receptors?

Answer 2

Respond to mechanical stimulation

Located in skin

Question 3

Function of thermal receptors?

Located in skin

Answer 3

Respond to temperature changes

Question 4

Function of chemical receptors?

Answer 4

Respond to chemical stimuli

Located near organs

Question 5

Interoception

Answer 5

Internal stimuli about organ function

Hunger, thirst, breathlessness

Question 6

Proprioception

Answer 6

Awareness of body position/movement in space

Question 7

Location of mechanical receptors?

Answer 7

Near skeletal muscle, joint capsules, skin

Question 8

First-order neuron

Answer 8

Neuron with cell body in dorsal root ganglion of spine

Question 9

Second-order neuron

Answer 9

Neuron with cell body in spinal cord or brainstem

Question 10

Function of thalamus?

Answer 10

Relay station for sensory information

Question 11

Third-order neuron

Answer 11

Neuron with cell body in thalamus

Question 12

Function of dorsal root ganglion neurons?

Answer 12

Transduction and transmission of somatosensory information

Question 13

Transduction

Answer 13

Process of converting physical stimuli into electrical signals

Question 14

Transmission

Answer 14

Process of sending electrical signals through neurons

Question 15

What do peripheral branches innervate?

Answer 15

Touch mechanoreceptors

Question 16

Where does the Central branch synapse onto?

Answer 16

Second-order neuron in spinal cord or brainstem

Question 17

Function of proprioceptors

Answer 17

Provide awareness of body position

Question 18

Function of nociceptors

Answer 18

Respond to pain

Question 19

Thermoreceptors

Answer 19

Respond to temperature changes

Question 20

Function of mechanoreceptors?

Answer 20

Respond to mechanical stimulation

Question 21

Group I/Aa fibers

Answer 21

Proprioceptors in muscles

Question 22

Group II/Ab fibers

Answer 22

Touch receptors in skin

Question 23

Group III/Ac fibers

Answer 23

Pain and temperature receptors

Question 24

Group IV/C fibers

Answer 24

Temperature, pain, and itch receptors

Question 25

# True or False? All 4 types of touch receptors conduct at the same speed.

Answer 25

True | (at Ab)

Question 26

Function of SA1 (Merkel cells/disk) touch receptors

Answer 26

* Respond to light touch, edges, corners, points * Detect form, texture, curvature (crude touch information)

Question 27

Function of SA2 (Ruffini endings) touch receptors?

Answer 27

* Respond to stretching of skin * Detect stretching, hand shape, motion direction

Question 28

Function of RA1 (Meissner corpuscle) touch receptors?

Answer 28

* Respond to large movements, vibration (fine touch information) * Detect motion, grip control

Question 29

Function of RA2/PC (Pacinian corpuscle) touch receptors?

Answer 29

* Respond to small movements (vibration) * Detect vibrations in skin when using tools (pencils, keys, etc.)

Question 30

Mechanoreceptor transduction

Answer 30

* Physically deforms cell membrane, stretching out receptors * Allows cations in to depolarize cell

Question 31

# True or False? The firing rate in mechanoreceptor transmission corresponds to SA/RA designation.

Answer 31

True

Question 32

# True or False? The trigeminal nerve (V) enters the CNS via the spinal cord.

Answer 32

False | It enters the CNS via the pons.

Question 33

Location of cell body of Principal/Main sensory nucleus

Answer 33

Trigeminal ganglia mid-pons

Question 34

Location of Spinal nucleus

Answer 34

Trigeminal ganglia in medulla/lower pons (elongated)

Question 35

Parts of Trigeminal Nuclei:

Answer 35

* Principal/Main sensory nucleus * Spinal nucleus * Motor nucleus

Question 36

Where do secondary fibers decussate and travel up in the trigeminothalamic tract to?

Answer 36

The ventral posteromedial nucleus (VPM) of thalamus

Question 37

What does the principal/main sensory nucleus represent?

Answer 37

Pressure and vibration

Question 38

What does the spinal nucleus represent?

Answer 38

Mechanosensation, pain, temperature