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Flashcards in Somatosensory 1 Deck (43)
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1
Q

What are low-threshold units?

A

respons to low intensity stimuli (non-damagin and non painful)

2
Q

What other name are high threshold units known by»

A

nociceptors

3
Q

What is adaptation?

A

a feature of primary sensory neurones that determines whether they change their firing rate only in response to a stimulus of chagning intensity or fire continuously throughout a constant stimulus

4
Q

What is a slowly adapting response?

A

continous information to CNS hile terminal deformed

5
Q

What type of information do slowly adapting responses give?

A

position, degree of stretch of force eg stretch receptors

6
Q

What are rapidly adapting responses?

A

detects changes in stimulus strength, the number of impulses is proportional to the rate of change of stimulus

7
Q

Give examples of rapidly acting afferents?

A

some muscle spindles and hair follicle afferents

8
Q

What are very rapidly adapting responses?

A

responds only to very fast movemnt such as rpid vibration

9
Q

Give an example of a rvery rapidly adapting responses?

A

pacinian copuscle

10
Q

What type of axon have the thickest myelination?

A

group 1/ Aa fibres

11
Q

What type of modality are group 1/Aa fibres?

A

proprioceptors of SK muscle

12
Q

What modality are group II or Ab fibres?

A

mechanoreceptors of skin

13
Q

What modality are group III or Ad fibres?

A

pain and temperature

14
Q

What modality are group IV or C fibres?

A

temperature, pain and itch

15
Q

What is the receptive field of an afferent neurone?

A

the region that when stimulate with an adequate stimulus causes a response in that neurone

16
Q

What is the relationship with discriminative capacity and receptive field?

A

regions with the highest discriminative capacity have the smallest receptive fields

17
Q

What modality do free nerve endings carry?

A

pain, heat and cold

18
Q

Where are Meissner’s corpuscles found?

A

in skin location where two point discrimination is highest, not in hairy skin

19
Q

What modality do Meissner’s corpuscles carry?

A

touch- stroking,flutter

20
Q

What modality do Merkel’s discs carry?

A

touch- pressure and texture

21
Q

Where are Merkel’s discs found?

A

abundant where two point discrimination is highest, some in hairy skin

22
Q

How are Merkel’s discs often grouped?

A

in Iggo domes

23
Q

Where are Krause end bulbs found?

A

at the border of dry skin and mucous membranes

24
Q

What modality do Krause end bulbds carry?

A

touch

25
Q

Where are Ruffini endings found?

A

within dermis and joint capsules

26
Q

What modality do Riffini endings carry?

A

pressure- skin stretch

27
Q

Where are Pacinian corpuscles found?

A

within dermis and fascia

28
Q

What modality do Pacinian cospuscles carry?

A

vibration

29
Q

What modality do C mechanoreceptors carry?

A

stroking, social and erotic touch

30
Q

What is the adaption of Meissner’s corpuscles?

A

RA

31
Q

What is the adaption of Merkel disc receptors?

A

SA

32
Q

What is the adaption of Pacinian corpsucles?

A

very RA

33
Q

What is the adaption of Ruffini endings?

A

SA

34
Q

What is the receptive field of Pacinian corpuslces compared to Meissners corpuslces?

A

Meissner’s corpuscles have much smaller RFs than pacinian cospuscles

35
Q

What nerve group has a similar RF to Pacinian corpuscles?

A

Ruffini endings

36
Q

What nerve group has a similar RF to Meissner’s corpuscles?

A

Merkel disc

37
Q

Where are free nerve endings found?

A

epidermis

38
Q

What is the fibre class of nociceptors?

A

Ad/C

39
Q

What is the fibre class of low threshold mechanoreceptors?

A

Ab

40
Q

What is the fibre class of proprioceptors?

A

Aa

41
Q

Where is the termination of nociceptors in the dorsal horn?

A

laminae I and II

42
Q

Where is the termination of LTMs in the dorsal horn?

A

laminae III to VI

43
Q

Where is the termination of proprioceptors in the dorsal horn?

A

laminae VII to IX