Neuroscience part 2

Question 1

Dermatome

Answer 1

Area of skin innervated by afferent axon fibres

Made up of specific receptive fields

Question 2

Phasic receptor

Answer 2

Fast adapting
Constantly changing stimulus required
Useful when it’s important to signal a change in stimulus and stop paying attention to unimportant stimuli
i.e tactile receptors

Question 3

Tonic receptor

Answer 3

Slow/ non adapting
Important when maintaining information about a valuable stimulus
i.e stretch & pain

Question 4

Meissners Corpuscle

Answer 4

Fast Adapting

Constantly changing stimulus

Question 5

Merkels Receptor

Answer 5

Slow adapting

Sustained light touch

Question 6

Ruffinis Corpuscle

Answer 6

Slow adapting

Deep touch/ stretch

Question 7

Pacinian corpuscle

Answer 7

Fast adapting

Stronger stimulus, deep touch, poke

Question 8

Hair follicle receptor

Answer 8

Fast adapting

Question 9

Lemniscal/ Dorsal Column Pathway

Answer 9

large sensory A𝛿 fibres- touch & vibration

Dorsal Column, Spinal Cord, Medulla, Decussate at medial lemniscus, Thalamus, Primary somatosensory

Question 10

Spinothalamic Pathway

Answer 10

Small A𝛿 & C fibres- pain & temp

Dorsal Column, Decussate, Spinal Cord, Medulla, Thalamus, Primary Somatosensory Cortex

Question 11

Cutaneous Thermoreceptors

Answer 11

Bare nerve endings
Slowly adapting sensory receptor
Poor indicators of absolute temp
V sensitive to changes in temp

Question 12

TRPV3/4

Answer 12

Warm
Channels open 29-45
C fibres

Question 13

TRPM8

Answer 13

Cold
Channels open 8-38
C & A𝛿 fibres

Question 14

TRPA1

Answer 14

Cold
<17
C & A𝛿 fibres

Question 15

Cutaneous Nociceptors

Answer 15

Non adapting sensory receptor

Adequate stimulus must be capable of damaging tissue

Question 16

High threshold mechanoreceptors

Answer 16

A𝛿 fibre

Well localised pricking pain

Question 17

Polymodal Nociceptor

Answer 17

C fibre
Sensitive to mechanical stimulus, damaging heat (>46) and noxious chemicals
Poorly localised burning pain

Question 18

Proprioception

Answer 18

Detects mechanical status of musculo - skeletal system

Question 19

Muscle Spindle

Answer 19

Detection of length and acceleration

1a afferents

Question 20

Golgi Tendon Organ

Answer 20

Detection of muscle tension

1b afferents

Question 21

Touch neurones

Answer 21

Thick & myelinated

aβ fibre afferent

Question 22

Pricking Pain neurones

Answer 22

Thinner & myelinated

aβ fibre afferent

Question 23

Noxious Heat neurones

Answer 23

Thinner & non myelinated

C fibre efferent

Question 24

Function of simple reflexes

Answer 24

Protective
Postural Control
Homeostasis

Question 25

Monosynaptic Reflex Pathway

Answer 25

i.e muscle spindle No interneurones Sensory neurone, spinal cord, motor neurone

Question 26

Polysynaptic Reflex Arc

Answer 26

I.e Golgi tendon organ Prevents over contraction Sensory neurone, Interneurone (inhibitory) Motor neurone As muscle contracts, pulls on tendon Pressure on nerve endings Increased activity sensory neurone Increased activity inhibitory interneurones Decreased activity in efferent i.e activity too great, inhibits contraction of muscle --> Drop item

Question 27

Knee Jerk Reflex

Answer 27

``` Must have simultaneous contraction of quadriceps & relaxation of hamstring Polysynaptic --> Inhibitory Interneurone Pulls on quadricep muscle Activates spindle Monosynaptic Arch ```

Question 28

Crossed Extensor Reflex

Answer 28

Withdrawal reflex +/- interneurones Opposite on two legs Stand on one foot while raise other i.e if you stand on a pin

Question 29

Sympathetic innervation

Answer 29

Short pre-ganglionic neurone Long post-ganglionic neurone Acetylcholine at ganglion, noradrenaline at fibre

Question 30

Parasympathetic innervation

Answer 30

Long pre-ganglionic neurone Short post-ganglionic neurone Acetylcholine at ganglion and fibre

Question 31

Adrenal Medulla

Answer 31

Sympathetic input on adrenal medulla causes release of adrenaline and noradrenaline in bloodstream