Receptors

Question 1

Mention site of proprioceptors

Answer 1

Joint capsules, fascia, ligaments
Muscle as muscle spindle
Tendon as golgi tendon organ

Question 2

Classify receptors

Answer 2

Mechanoreceptors
Chemoreceptors
Thermoreceptors
Nociceptors
Photoreceptors

Question 3

S&F of free nerve endings

Answer 3

S, the epidermis of skin (numerous), cornea, mucuous membrane of visceral organs, serous membranes, muscles, deep fascia.
F, crude touch, noxious stimuli (pain), thermal stimuli

Question 4

S&F of peritrichial nerve endings

Answer 4

S, around hair follicles
F, mechanoreceptors

Question 5

Describe shape of peritrichial nerve endings

Answer 5

The naked fibers branch and form basket-like aborization around CT sheath if hair follicle below sebacceous gland

Question 6

S&F of Merkel’s tactile disc

Answer 6

S, deep layers of epidermis of palmar surface of hands and plantar surface of foot + transition regions between hairy and non-hairy skin
F, mechanoreceptors, vertical sustained pressure (holding a pen)

Question 7

Describe EM of picture of Merkel’s t.d.

Answer 7

Have cytoplasmic prohections which extend between keratinocytes to which they are joined by desmosomes

Question 8

Concave terminal disc in Merkel’s t.d. Is …….

Answer 8

Tactile meniscus

Question 9

S&F of Meissner’s corpuscles

Answer 9

S, in dermal papillae of palms, fingertips, soles, nipples, eyelids & external genitalia
F, crude touch & 2 point discrimination

Question 10

S&F of Pacinian corpuscles

Answer 10

S, dermis & hypodermis, pancreas, mesentery, external genitalia & wall of urinary bladder
F, deep pressure & vibration (mechano.)

Question 11

Compare inner and outer cores of pacinian corpuscles

Answer 11

I, cells are small, thin and closey packed together with very narrow intercellular spaces. They form semicircles around afferent fibers.
O, cells are larger, thicker and widely separated. They form complete concentric layers around inner part of the core.

Question 12

S&F of Ruffini corpsucles

Answer 12

S, Dermis and subcutaneous tissue, palm & sole
F, mechanoreceptors, respond to tension in surrounding collagenous fibers

Question 13

S&F of genital corpuscles & their other name

Answer 13

S, conjunctiva, tongue, mouth, extenal genitalia
F, mechanoreceptors
N, Krause’s end bulbs & mucocutaneous corpusles

Question 14

Mention the receptor which is both extero & proprioceptive

Answer 14

Pacinian corpuscle

Question 15

General function of proprioceptors

Answer 15

Stretch receptors for regulation of spinal myotactic reflex or project to cerebellum to regulate muscle tone & synergy

Question 16

S&F of neuromuscular spindles

Answer 16

S, skeletal muscles, more numerous in extremities & muscles of fine control (fingers)
F, stimulated by active stretch by contraction of intrafusal fibers & passive stretch when the is pull on tendon

Question 17

Compare nuclear bag & chain fibers

Answer 17

Bag, 1-4 in number (few), thich & long, the central part is expanded and contains numerous nuclei
Chain, up to 10 (numerous), thin & short, the central part is narrow & contains a chain of nuclei

Question 18

Compare primary afferents & secondary afferents in muscle spindle

Answer 18

P, a terminal branch of large myelinted sensory fiber, winds in a spiral form arround nuclear areas of intrafusal fibers forming annulospiral endings.
S, a terminal branch of smaller sensory fiber, terminate on each side of annulospiral ring forming clusters known as flower spray endings.

Question 19

Motor fibers of muscle spindles are …… fibers

Answer 19

Gamma

Question 20

S&F of neuro-tendinous organs

Answer 20

S, at junctions of muscles with their tendons
F, tendon organ detects changes in muscle tension. They provide CNS with information regarding tension in muscle

Question 21

Mention joint receptors and their site

Answer 21

1. Golgi tendon organ is found in internal & external ligaments
2. Diffused free nerve endings, Ruffini corpuscles & pacinian corpuscles in capsule
3. Pacinian corpuscles in synovial membranes