Exteroception

Question 1

What is columnar organization?

Answer 1

the vertical arrangement of functionally related cells (barrels) of the cortex

Question 2

What info does the antero-lateral system convey?

Answer 2

• pain
• temperature
• crude touch

Question 3

What are slowly adapting receptors?

Answer 3

those that will keep firing when stimulated by steady touch throughout the time the skin is pressed

Question 4

The lemniscal system for the head involes the ______.

Answer 4

trigeminal nerve

Question 5

Name the receptor:

• fast adapting
• large receptive field
• vibration sensation

Answer 5

Pacinian corpuscles

Question 6

Afferent information about touch, proprioception, pain, and temperature on the face and head flow through the _____.

Answer 6

trigeminal nerve

Question 7

What are the key features of Pacinian corpuscles?

Answer 7

• fast adapting
• large receptive field
• vibration sensation

Question 8

Name the receptor:

• slow adapting
• large receptive field
• stretch sensation/grip

Answer 8

Ruffini’s endings

Question 9

Name the receptor:

• rapidly-adapting
• small receptive fields
• fine tactile sensation

Answer 9

Meissner’s Corpuscles

Question 10

What are the 3 branches of the trigeminal nerve?

Answer 10

1. opthalamic
2. maxillary
3. mandibular

Question 11

Name the receptor:

• slow adapting
• small receptive fields
• fine tactile sensation

Answer 11

Merkel’s discs

Question 12

The cell bodies of mechanoreceptors from skin and proprioceptors are found where?

Answer 12

in the dorsal root ganglia

Question 13

What info does the dorsal column/lemniscal system (posterior column) convey?

Answer 13

• fine, discriminative touch
• limb proprioception

Question 14

What are the key features of Meissner’s Corpuscles?

Answer 14

• rapidly-adapting
• small receptive fields
• fine tactile sensation

Question 15

What are the key features of Ruffini’s endings?

Answer 15

• slow adapting
• large receptive field
• stretch sensation/grip

Question 16

What is the significance of the horizontal layers of organization in the cortex?

Answer 16

to project to and receive projections from different areas of the brain for proper distribution

Question 17

What system transmits info about pain, temperature, and crude touch?

Answer 17

the antero-lateral system

Question 18

What system transmits info about fine, discriminative touch and limb proprioception?

Answer 18

the dorsal column/lemniscal system (posterior column)

Question 19

Mechanoreceptors of the skin and joint receptors have _____ fibers.

Answer 19

Aβ

Question 20

What is a receptive field?

Answer 20

the area of the skin in which a mechanical stimulus elicits a response from the cell

Question 21

Name the 2 broad somatosensory receptors based on size of receptive field.

Answer 21

• small fields (2-8mm with sharp borders) = Meissner’s corpuscles and Merkel’s discs
• large fields (entire finger or greater area, poorly defined)= Pacinian corpuscles and Raffini endings

Question 22

What is the somatosensory system?

Answer 22

the collection of receptors that transduce info about the body surface and deeper tissues

Question 23

What is the significance of the columnar organization in the cortex?

Answer 23

they vertically separate cells by response modality

Question 24

Proprioceptors of skeletal muscle have ____ fibers.

Answer 24

Aα

Question 25

What are the key features of Merkel’s discs?

Answer 25

• slow adapting
• small receptive fields
• fine tactile sensation

Question 26

What are rapidly adapting receptors?

Answer 26

those that, when stimulated, fire a few APs and then stop firing even though the stimulus is still there

Question 27

What are the 2 major subdivisions of the somatosensory system?

Answer 27

1. dorsal column/lemniscal system (posterior column)
2. antero-lateral system

Question 28

What is somatotopy?

Answer 28

the precise and orderly mapping of the body surface onto the cortex