Cutaneous perception Flashcards Preview

Nervous system > Cutaneous perception > Flashcards

Flashcards in Cutaneous perception Deck (42)
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1
Q

What are the sensory modalities?

A

Light, sound, taste, temperature, pressure and smell

2
Q

What does a mechanoreceptor detect?

A

Touch, pressure, vibration, proprioception

3
Q

What do thermoreceptors detect?

A

Changes in temperature

4
Q

What do nociceptors detect?

A

Pain resulting from physical or chemical change

5
Q

What do free nerve endings detect?

A

Pain, thermal, tickle, itch, some touch

6
Q

What do encapsulated nerve endings detect?

A

Touch, pressure, vibration

7
Q

Characteristics of encapsulated nerve endings

A

Large axon diameter

Myelinated A fibers

8
Q

Characteristics of free nerve endings

A

Small axon diameter

Unmyelinated C fibers

9
Q

What are the two touch modalities?

A

Crude and fine touch

10
Q

What is crude touch?

A

No information about location, size, shape, texture

11
Q

What are the two types of receptors?

A

Rapidly acting and slowly acting

12
Q

What are the two rapidly adapting receptors?

A

Meissner corpuscle

Hair root plexus

13
Q

Where are Meissner corpuscles found?

A

Hairless skin, e.g. hands, lips, tongue etc

14
Q

Where are hair root plexuses found?

A

Around hair follicles

15
Q

What are the two types of slowly adapting receptors?

A

Merkel discs

Ruffini corpuscles

16
Q

Characteristics of Merkel discs

A

Detect fine touch

Free nerve endings, found in epidermis

17
Q

Characteristics of Ruffini corpuscle

A

Encapsulated nerve endings
Deep in dermis
Sensitive to stretching during movement

18
Q

Which receptors detect pain?

A

Nociceptors

19
Q

Where are nociceptors found?

A

Everywhere except the brain

20
Q

Characteristics of nociceptors

A

Free nerve endings, little adaptation

21
Q

When are nociceptors activated?

A

Intense mechanical, thermal or chemical stimuli capable of causing damage

22
Q

Characteristics of fast pain

A

Within 0.1 sec, acute and sharp pain, carried by myelinated A-delta which are precisely located, very fast AP

23
Q

Characteristics of slow pain

A

More than a second, chronic and burning pain, carried by unmyelinated C fibers (AP is slower), diffusely located, intensity increases over time

24
Q

Function of proprioceptors

A

Prevent tissue damage from excessive muscle extension

Information on body position (muscle contraction, tension in tendons, position of joints)

25
Q

Function of muscle spindle

A

Detect changes in muscle stretch

26
Q

Function of Golgi tendon organs

A

Detect changes in tendon tension and protect from excessive tension

27
Q

Function of joint kinaesthetic receptors

A

Monitor stretch in synovial joints and provide information about joint position and movement

28
Q

Characteristics of thermoreceptors

A

Free nerve endings, rapidly adapting but sustain firing at low frequencies

29
Q

Characteristics of cold receptors

A

Abundant, can have myelinated A-delta or unmyelinated C fibers, activated between 10-40 degrees

30
Q

Characteristics of warm receptors

A

Unmyelinated C fibres, activated between 32-48 degrees

31
Q

Characteristics of dorsal column-medial lemniscal

A

Discriminative touch, crossover in medulla, cuneate nucleus (upper body), gracile nucleus (lower body)

32
Q

Characteristics of corticospinal tract

A

Motor (descending), crossover in spinomedullary junction

33
Q

Characteristics of spinocerebellar tract

A

Proprioception, no functional crossover

34
Q

Characteristics of spinothalamic tract

A

Pain and temperature, crossover in spinal cord

35
Q

What impact does decussation have?

A

The RHS of the bra

36
Q

Function of spinothalamic tract

A

Routes pain information from spinal cord to brainstem and thalamus, information then relayed to somatosensory cortex (pain perception)

37
Q

Function of spinofeticular tract

A

Emotional response to pain, descending modulation of pain processing

38
Q

Effect of thalamic lesion

A

Sensory loss throughout opposite side

39
Q

Effect of brain stem lesion

A

Contralateral sensory loss below face and ipsilateral on face

40
Q

Effect of central cord lesion

A

Areas of loss, often asymmetrical and dissociated

41
Q

Effect of unilateral cord lesion/hemisection

A

Contralateral spinothalamic loss; ipsilateral corticospinal muscle weakness and dorsal column (touch) loss

42
Q

Effects of tranverse cord lesion

A

Loss of all sensory and motor modalities below the lesion