Somatosensory

Question 1

What are the sensory submidalities?

Answer 1

Mechanoreceptors (touch vibration and pressure)
Thermoreceptors (temperature)
Nociceptors (pain)

Question 2

What are the specialized nerve endings for mechanoreceptors?

Answer 2

Merkel’s disk, Meissner’s corpuscule, Pacinian Corpuscule, Ruffini ending

Question 3

What are free nerve endings connected to?

Answer 3

Thermal receptors and nociceptors

Question 4

What are the two components of proprioception?

Answer 4

Sense muscle length and tension

Question 5

Which mechanoreceotor is linked with muscle length sense?

Answer 5

Muscle spindles

Question 6

Which mecanireceptor is linked with muscle tension sense?

Answer 6

Golgi tendon organs

Question 7

What are the four qualities of a stimulus?

Answer 7

Modality, location, intensity and duration

Question 8

What are the 5 sensory modalities?

Answer 8

Vision, hearing, touch, taste, smell

Question 9

What enhances the spatial resolution of the 2nd order neurons’ receptive fields?

Answer 9

The neurons’ surround (lateral) inhibition

Question 10

What are the 4 spinal segments

Answer 10

Cervical, thoracic, lumbar, sacral

Question 11

Each spinal segment provides … to a particular region of the skin

Answer 11

Sensory inervation

Question 12

What is the dermatome?

Answer 12

The area of skin and deeper tissues innervantes by a single dorsal root

Question 13

What are the two sensory pathways?

Answer 13

Dorsal column-medial lemniscal system

Spinothalamic tract

Question 14

What is the dorsal column-medial lemniscal pathway responsible for?

Answer 14

Vibration, light touch, pressure, proprioception

Question 15

What is the spinothalamic tract responsible for?

Answer 15

Pain and temperature

Question 16

What are where are the 3 neurons responsible for the two pathways?

Answer 16

1) 1st order neuron which is the dorsal root ganglion cell
2) 2nd order neuron is ipsilateral to neuron 1 and is located in spinal cord
3) 3rd order neuron in thalamus

Question 17

What are the 5 steps of the dorsal column-medial lemniscal pathway?

Answer 17

Dorsal columns (spinal cord)
Dorsal column nuclei (medulla)
Medial lemniscus (brainstem)
Ventral posterior lateral nucleus (VPL, thalamus)
Primary sensory cortex, S1

Question 18

What do pain and temperature activate?

Answer 18

Transient receptor potential ion channels

Question 19

What do lightly myelinated Aalpha fibers register?

Answer 19

Fast, sharp first pain

Question 20

What do unmyelinated C fibers register?

Answer 20

Register duller, longer lasting second pain

Question 21

What are the two steps of the spinothalamic tract?

Answer 21

Aalpha and C afferents synapse in the substantia gelatonisa of dorsal horn

Decussate and travel up the cord in the spinothalamic tract to the thalamus (VPL) and then to S1

Question 22

What are the 3 elements for which the posterior parietal cortex is responsible?

Answer 22

1) involved in somatic sensation
2) analysis where things are from visual inputs
3) involved in sensation of where things are on your body or your interpersonal space