Sensory Receptors

Question 1

pacinian corpuscle

Answer 1

large, lamellar, rapidly adapting mechanoreceptor that detects gross pressure and vibratory skin stimuli. Sends AP at onset and offset of stimulus, but nothing during maintained stimuli.
Location: subcu, joints, muscle and mesentery

Question 2

meissner’s corpuscle

Answer 2

rapidly adapting mechanoreceptor that detects light touch and vibration.
Location: glabrous skin below epidermins

Question 3

Merkel disk

Answer 3

slowly adapting mechanoreceptor

location: skin and mucosa, fingertips or touch domes/hair disks

Question 4

Ruffini organs

Answer 4

slowly adapting mechanoreceptors that respond to sustained pressure and skin stretch. Slipping and position sense.
location: only in depp layers of glabrous skin

Question 5

Free nerve endings

Answer 5

responsive to temperature and nociceptive stimuli

Question 6

What types of afferent fibers innervate muscle spindles?

Answer 6

type Ia  (connected to annulospiral ending)  = length and velocity info
and type II = fiber length

Question 7

What types of afferent fibers innervate Golgi tendon organs?

Answer 7

type Ib. When activated, will inhibit alpha motor neuron to prevent muscle damage

Question 8

What type of efferent fiber innervates intrafusal motor fibers?

Answer 8

gamma

Question 9

What type of efferent fiber innervates extrafusal fibers?

Answer 9

alpha-efferent

Question 10

What is happening to the muscle if a muscle spindle type II fiber increases its firing rate?

Answer 10

muscle is being lengthened.

If rate slows, then muscle is shortening.