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Flashcards in somatosensory physiology Deck (39):
1

What are the main types of sensation

pain- inside and outside
propriception- vital for movement.
Temperature- inside and outside
Pressure- inside and outside
Vibrations-different from pressure- different from pressure dorsal column.

2

where are sensory receptors located

throughout the body

3

what are the main types of sensory receptors.

tactile (innocuous), nociceptive, proprioceptive, thermal.

4

what receptors stimulates tactical (innocuous) sensations

mediated by low threshold mechanoreceptors, merkel, ruffini, messier and pacianian types.

5

what stimulates proprioception

mediated by muscle (spindle) and joint (Golgi tendon) receptors, some inputs from cutaneous mechanoreceptors.

6

what stimulates thermal sensations

mediated by thermo receptors localized to discrete zones that exhibit hot an cold sensitivity.

7

what stimulates noiceptive sensations

mediated by mechanical, thermal & polymodal nociceptors.

8

where are ruffini's corpuscle located

deep in the dermis

9

where are pacinian corpuscles located

encapsulated endings in the subcutaneous tissue

10

where are merkel's and meissners located

beneath the epidermis.

11

which receptor type is commonly used in braille

merkel' s recepetors

12

what is the structure of meissner's corpuscles

looping axonal terminals that inter-twine supporting cells

13

what is the structure of merkel's receptors

dome structure atop axon terminals

14

what is the structure of pacinian corpuscles

sensory axon surrounded by fluid filled capsule

15

what is the structure ruffini endings

nerve terminals intertwined with collagen fibrils

16

what is the structure of nociceptors

free nerve endings that penetrate epithelial cells, no morphological specialization.

17

how are the receptive fields of cutaneous sensory receptors tested

a) Testing the receptive field of sensory receptors using a stimulus probe on the hand, and recording action potentials from a single median nerve axon.
b) Results for main types of cutaneous sensory receptors.

18

which receptors are slow adapting and which receptors are fast adapting

slow receptors- merkel and ruffini
fast receptors- meissner and pacinian corpuscle

19

which areas of the body have high sensory innervation and can distinguish 2 points

fingertips, face

20

which 2 types of receptors are involved in 2 point touch

merkel's and meissner's

21

what receptor activated by the hot

Capsaicin activates Trpv1

22

what receipts is activated by the cold

Menthol activates Trpm8

23

what natural substance is capsaicin found in

chilli pepper.

24

capsaicin belongs to which group of family

vanilloids

25

what type of receptor does capsaicin work on

thermal receptor
heat and for hot food.

26

what is the function of a muscle spindle fibre

Provide sensory feedback from muscle fibres on body position and movement

27

what is the function of the golgi tendon organ

Golgi tendon organs regulate muscle tension or force of contraction and prevent muscle overload.

28

what types of receptors are large in diameter and rapidly conduct afferents

mechanorecpetors and proprioceptors.

29

what types of receptors are small in diameter and slow conducting

nociceptors and thermoreceptors.

30

define dermatome

a region of the skin which is up plied by a single myotome.

31

do dermatomes have definite boundaries

no-overlap occurs.

32

what condition/ infection commonly has a dermatome specific presentation

herpes zoster.

33

where is the primary somatosensory cortex and what is it's function

post central gyrus
Areas are specialized e.g processes information from skin on texture, shape & size.

34

what is the secondary somatosensory cortex and what is it's function

adjacent to primary somatosensory cortex.
Plays a key role in sensory and motor integration
Receives corpus callosum inputs to form ‘joined -up’ body image
Build info from multiple body areas, body image

35

where does the secondary somatosensory cortex receive information from

corpus callosum

36

where are the association centres and what are it's function.

Localized to posterior parietal cortex
Plays role in integration of multimodal senses

37

what did penfield discover

each part of the body is represented on two strips of the brain's cerebral cortex, the somatosensory cortex ("sensory homunculus" ), which receives sensations of touch, and the motor cortex ("motor homunculus”) which controls movements.

38

what did broadman discover

devised Brain into 47 areas, which had subserved different physiological functions.

39

Damage to posterior parietal cortex produces unusual neurological disorders: which include.

Astereoagnosia, the inability to identify objects on basis of touch alone.

Neglect syndrome, body part or visual field is disregarded.