Sense of Touch

Question 1

Name the three layers of skin (outside to inside)

Answer 1

Epidermis, Dermis, Hypodermis

Question 2

What does Dermis contain? (also name the specific receptors)

Answer 2

Blood vessels, Merkel’s Disks, Meissner Corpuscle

Question 3

What does Hypodermis contain? (also name the specific receptos)

Answer 3

Attached to muscles, Pacinian Corpuscle, Ruffini’s ending

Question 4

Name the 4 receptors that detect light touch and which types of touch they detect

Answer 4

Merkel’s disk - edges
Meissner’s corpuscle - edges
Pacinian corpuscle - Vibration (texture of surfaces)
Ruffini’s ending - stretch

Question 5

which of the four studied touch receptors are fast-adapting (phasic)?

Answer 5

Meissner’s corpuscle and Pacinian corpuscle

Question 6

which of the four studied touch receptors are slow-adapting (tonic)?

Answer 6

Merkel’s disks and Ruffini’s eding

Question 7

What is piezo2?

Answer 7

Piezo2 is a typr of ion channel in the membrane of Meissner’s corpuscle and Merkel’s disk that opens at a mechanical strethc - for this reason, it can detect edges of objects well.

Question 8

What is the name of the sysem that carries Touch information to the brain?

Answer 8

Dorsal Column System

Question 9

Do the nerve fibers of the dorsal column system, once they have entered the central nervous system through the dorsal root ganglia, immediately cross the midline of the spinalchord? Wherelse if not immediately?

Answer 9

No, they cross at the medulla

Question 10

Where do the fibers of the dorsal column system first synapse and on what do they synapse?

Answer 10

The first synapse at the medulla and the synapse on dorsal column nuclei

Question 11

The three carrier cells (yes I just made up a term, don’t use this in an exam) does touch info pass through in the dorsal column system?

Answer 11

Abeta fibers -> dorsal column nuclei -> cortical cells