Sensory Pathways 1

Question 1

what are the 3 stages of senses

Answer 1

detection
transmission
recognition

Question 2

what are the two main types of receptors

Answer 2

cutaneous

special senses

Question 3

A alpha/ group 1

Answer 3

proprioceptors

Question 4

A beta/ group 2

Answer 4

mechanoreceptors of skin

Question 5

A delta/ group 3

Answer 5

pain temperature

Question 6

C / group 4

Answer 6

temperature/ pain/ itch

Question 7

free nerve endings

Answer 7

non specialist
pain
C and A delta
slowly adapting

Question 8

merkel’s disks

Answer 8

static touch and pressure
A beta, epithelial cell and nerve fibre
slowly adapting
lips, extremities and genitals

Question 9

meissner’s corpuscles

Answer 9

encapsulated nerve endings, dermal papillae, changes in touch and pressure, A beta
fingers, palmar and plantar surfaces

Question 10

Pacini’s corpuscles

Answer 10

largest mechanoreceptors
onion like encapsulation of nerve endings
vibration
A beta

rapidly adapting
hands feet, nipples

Question 11

hair follicle receptors

Answer 11

sensitive to hair movements

Question 12

ruffini corpuscle

Answer 12

skin stretch

Question 13

measures changes in length of muscle

Answer 13

muscle spindles

Question 14

how do muscle spindles regulate muscle length

Answer 14

gamma reflex loop

Question 15

describe the gamma reflex loop

Answer 15

when intrafusal fibres are stretched afferent fibres stimulate contraction of extrafusal fibres via alpha motor neurones

Question 16

golgi tendon organs

Answer 16

detect tension in the muscle via type 1b sensory nerve endings which innervate a collagen matrixin the tendon

as the tendon stretches the endings depolaries and send information to the CNS

Question 17

Where do first order neurons projects to (conscious sensory tracts)

Answer 17

spinal cord or brainstem

Question 18

where do second order neurons project to (conscious sensory tracts)

Answer 18

thalamus

Question 19

where do third order neurons projects to (conscious sensory tracts)

Answer 19

cortex (somatosensory)

Question 20

intrafusal muscle fibres

Answer 20

proprioception

Question 21

what is the function of the thalamus

Answer 21

conduit for all sensory information except for some olfaction

reciprocal connections to all cortical regions and can relay information, recieve feedback and modulate cortical activity

Question 22

grey matter

Answer 22

cell bodies and dendrites

middle bit of spinal cord

Question 23

information from lower body extremities

Answer 23

fasciculus gracilis

Question 24

upper body extremities information

Answer 24

fasciculus cuneatus

Question 25

dorsal spinocerebellar tracts

Answer 25

proprioceptive information from muscle spindles

Question 26

ventral spinocerebellar (white matter)

Answer 26

proprioceptive information from golgi organs

Question 27

pain transmission in white matter of spinal cord

Answer 27

spinothalamic tract

Question 28

``` composed of A beta fibres fasc. gracilis fasciculus cuneatus ascend ipsilaterally synapse in the brainstem form the medial lemniscus and project to the ventral posterolateral lobe of the thalamus and then the cortex dorsal column nuclei ```

Answer 28

dorsal column medial lemniscus pathway conveys information from the skin and joints

Question 29

fasciculus cuneatus

Answer 29

above T6

Question 30

fasciculus gracilis

Answer 30

below t6

Question 31

what is lateral inhibition

Answer 31

the capacity of an excited neuron to reduce the activity of its neighbors. Lateral inhibition disables the spreading of action potentials from excited neurons to neighboring neurons in the lateral direction. relies on reciprocal inhibition between two adjacent neurons the purpose is to sharpen discrimination between two points

Question 32

what can cause gait ataxia

Answer 32

gracile fasciculus lesion due to the brain being deprived of sensory information from lower body extremities can be compensated with vision

Question 33

what does a stamp and stick gait imply

Answer 33

gait or sensory ataxia

Question 34

what could cause parasthesia in the distal extremities

Answer 34

dorsal column disease may be from ectopic discharge in dorsal column

Question 35

how can you test dorsal column function impairment

Answer 35

ability to feel changes in the position of toes and fingers or feel a tuning fork vibration also Romberg's sign- not a definitive sign

Question 36

what are the cortical functions of the dorsal column medial lemniscus pathway

Answer 36

determine the shape of an object without sight determine the texture of an object requires the somatosensory association area in the parietal lobe

Question 37

what is steriognosis

Answer 37

ability to detect 3D nature of an object and depth using touch

Question 38

what does a lesion of one somatosensory association cortex cause

Answer 38

amorphosynthesis patient is unaware of sensation on one side of the body, contralateral to the lesion patient cannot localise pain and temperature but can feel it