Discriminative Somesthesis

Question 1

Afferent nerves supplying the periodontal tissues (periodontal ligament, gingiva, and attached mucosa) are the peripheral processes of ______ and _______ neurons that course in the _______

Answer 1

trigeminal ganglion; trigeminal mesencephalic; maxillary and mandibular divisions of the trigeminal nerve

Question 2

Receptors in the periodontal ligament consist of several types of modified _____ and a variety of free nerve endings

Answer 2

Ruffini nerve endings

Question 3

The ______ are associated with larger myelinated nerve fibers and they are exquisitely sensitive to changes in forces applied to the teeth

Answer 3

Ruffini endings

Question 4

The Ruffini endings, very prominently associated with the periodontal ligaments, are ________, as they are in skin

Answer 4

slowly adapting mechanoreceptors

Question 5

What are the 3 functions of periodontal mechanoreceptors?

Answer 5

1. Tactile sensibility of the teeth
2. Discrimination of size, shape, texture and hardness of foodstuff or other objects placed in the mouth
3. Reflex motor control of the muscular movement of the mandible including mastication

Question 6

Threshold sensitivity is often tested with ______.

Answer 6

monofilaments (originally, von Frey hairs)

Question 7

____ varies across the body and is determined by sensitivity of rapidly adapting mechanoreceptors, although perception of pressure per se is mediated by slowly adapting mechanoreceptors

Answer 7

Threshold sensitivity

Question 8

____ is the measure of spatial resolution of touch.

Answer 8

Tactile acuity

Question 9

What is the most common way to test tactile acuity?

Answer 9

tow point threshold

Question 10

____ are the most sensitive to vibration, particularly in the 100-400Hz range.

Answer 10

Pacinian corpuscles

Question 11

Perceptual Correlate: Detecting skin contact; low frequency vibration; shape movement across skin

Answer 11

Mechanoreceptor Type: Meisnner - FAI (RAI)

Question 12

Perceptual Correlate: Static pressure on skin; object shape, both static and moving

Answer 12

Mechanoreceptor Type: Merkel - SAI

Question 13

Perceptual Correlate: Detecting abrupt skin contact; high frequency vibration

Answer 13

Mechanoreceptor Type: Pacinian - FAII (also RAII or PC)

Question 14

Perceptual correlate: tissue stretch

Answer 14

Mechanoreceptor: Ruffini - SAII

Question 15

Electrical Stimulation: Pressure, but no sense of contact

Answer 15

Mechanoreceptor Type: Merkel - SAI

Question 16

Electrical Stimulation: Tapping

Answer 16

Mechanoreceptor Type: Meisnner - FAI (RAI)

Question 17

Electrical Stimulation: Buzzing

Answer 17

Mechanoreceptor Type: Pacinian - FAII (also RAII or PC)

Question 18

In general, mechanoreceptors in orofacial tissues, including oral mucosa and the tongue resemble ____, _____, and to a lesser extent, _____ afferents in the skin of the hand

Answer 18

FAI, SAI, SAII

Question 19

Collectively, the mechanoreceptors in oral and perioral tissues are stimulated by _____ of their receptive fields

Answer 19

mechanical strain

Question 20

Ligamentous fibers (LF) of the PDL are innervated by _____ and _____ afferent fibers

Answer 20

mechanoreceptive; nociceptive

Question 21

Mechanoreceptive endings resemble ______ found in dermis, and respond to stretching of the ligaments associated with forces applied to the tooth

Answer 21

Ruffini cylinders

Question 22

Meissner’s corpuscles and Merkel’s receptors have the pattern that best matches the pattern for _____

Answer 22

tactile spatial acuity