Somatosensory Pathways and Tactile Receptors

Question 1

Uses LARGE MYELINATED FIBERS (Type II)
With temporal and spatial fidelity
Decussates near the medulla

Answer 1

DORSAL COLUMN MEDIAL LEMNISCUS PATHWAY

for speed and accuracy

touch sensations (requiring high degree of localization and fine gradation of intensity)

vibration

sensations that signal movement against the skin

position sense and fine pressure

2 point discrimination

Question 2

Uses smaller myelinated fibers (Type III and IV)

less fidelity

decussates IMMEDIATELY

Answer 2

ANTERO-LATERAL SYSTEM (SPINOTHALAMIC TRACT)

pain

temperature

light touch and pressure

tickle and itch

sexual sensation

Question 3

Crude touch, temperature, pressure

Answer 3

Free Nerve Endings

Question 4

Movements of objects

LOW FREQUENCY (slow vibration)

determines TEXTURE

Answer 4

Meissner Corpuscles (FA1)

Question 5

Gives steady state signals for CONTINUOUS TOUCH

localized touch sensation and to determine TEXTURE

Answer 5

Merkel Disc (SA1)

Combine to form IGGO DOME RECEPTORS

Question 6

Movement of object on the skin

Answer 6

Hair end organ

Question 7

Heavy and prolonged touch

detects SUSTAINED OR STEADY PRESSURE

signal DEGREE OF JOINT ROTATION

Answer 7

Ruffini Corpuscles (SA2)

Question 8

Detects DEEP PRESURE

HIGH FREQUENCY (FAST) VIBRATION

TAPPING

Answer 8

Pacinian Corpuscles (FA2)

onion shaped

Question 9

2 point discrimination

Answer 9

Merkel and Meissner