The Somatosensory System Flashcards Preview

Neurology > The Somatosensory System > Flashcards

Flashcards in The Somatosensory System Deck (40)
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1
Q

Deep sensation is from where?

A

Fascaie, muscles and bone

2
Q

What is exteroceptive sensation?

A

Cutaneous sensation from the surfaces of the body

3
Q

Neurotransmitter released following stimulation of sensory neurone

A

Glutamate

4
Q

What do joint and muscle mechanoreceptors sense?

A

Proprioception

5
Q

What word describes the following:

-the principle type of adequate stimulus that is transduced into an electrical signal by a primary afferent neurone

A

Modality

6
Q

Difference between low threshold thermoreceptors and thermal nociceptors

A

Low threshold thermoreceptors: mediate cold, cool, indifferent, warm and hot

Thermal nociceptors: respond to extreme degrees of heat (>45 degrees C) or extreme cole (

7
Q

What do chemical nociceptors respond to?

A

Substances in tissue (as found in inflammation) e.g. prostaglandins, bradykinin, serotonin, histamine, K+, H+, ATP and many others

8
Q

This is a feature of primary sensory neurones that determines whether they change their firing rate only in response to a stimulus of changing intesity, or if they fire continuously throughout a constant stimulus

A

Adaptation

9
Q

Slowly adapting receptors

A

Stretch receptors

10
Q

Rapidly adapting receptors

A

Some muscle spindle afferents, hair follicle afferents

detect changes in stimulus strangth e.g. rate of movement

11
Q

Very rapidly adapting receptors

A

e.g. Pacinian corpuscle (responds only to very fast movement, such as rapid vibration)

12
Q

Group I receptor

A

Proprioceptors of skeletal muscle

13
Q

Group II receptor

A

Mechanoreceptors of skin

14
Q

Group III receptor

A

Pain, temperature

15
Q

Group IV receptor

A

Pain, temperature, itch

16
Q

What is the receptive field?

A

The region that causes a response in a neurone if stimulated (i.e. the area that is innervated by neurone)

17
Q

What do free nerve endings sense?

A

Pain, heat, cold

18
Q

What do Meissner’s corpuscles and merkel’s discs sense?

A

Touch

19
Q

Where are Meissner’s corpuscles not present?

A

Hairy skin

20
Q

These receptors are often grouped in Iggo domes

A

Merkel’s discs

21
Q

What do Krause end bulbs sense?

A

Touch

22
Q

Where would you find Krause end bulbs?

A

At the border of dry skin and mucous membranes

23
Q

Where would you find Meissner’s corpuscles and Merkels discs?

A

Abundant in skin where 2 point discrimination is highest (remember meissner’s not present in hairy skin)

24
Q

Where would you find Ruffini endings?

A

Within the dermis and also joint capsules

25
Q

What do ruffni endings sense?

A

Skin stretch

Pressure

26
Q

What do pacinian corpuscles sense?

A

Pressure

27
Q

Where would you find pacinian corpuscles?

A

Within the dermis and fascia

28
Q

Area of skin innervated by the left and right dorsal roots of a single segment

A

Dermatome

29
Q

Innervation of the anterior head

A

Trigeminal system

30
Q

What makes up the white matter of the spinal cord?

A

Fibre tracts

31
Q

What makes up the grey matter of the spinal cord?

A

Cell bodies and sensory afferent terminals

32
Q

Mechanosensation

A

Touch, pressure and vibration

33
Q

What do low threshold units respond to?

A

Low intensity (non-damaging and non-painful) stimuli

34
Q

What do high threshold mechanreceptors respond to?

A

Respond to high intensity mechanical stimuli

35
Q

Responds only to very fast movement such as rapid vibration

A

Pacinian corpuscle

-very rapidly adapting!!

36
Q

These receptors are slowly adapting - continuous information to the CNS

A

Stretch receptors

37
Q

What evidence is there that receptive field varies greatly over the body surface?

A

Wide-differences in two point discrimination shows this

38
Q

These are often grouped in Iggo domes

A

Merkel’s discs

39
Q

Stroking and flutter

A

Meissner’s

40
Q

Vibration

A

Pacinian