organisation of the nervous system

Question 1

spinal cord: grey and white matter

Answer 1

boundary between CNS and PNS; grey matter: all cell bodies; white matter: where all fibres are (brain or periphery)

Question 2

posterior (dorsal) horn

Answer 2

dorsal root ganglia present (multiple cell bodies present); PNS sensory afferent neurone

Question 3

anterior (ventral) horn

Answer 3

no dorsal roots; PNS motor efferent neurone

Question 4

contralateral definition

Answer 4

as left hemisphere controls right side of body and vice versa, problems on other side to brain lesion

Question 5

ipsilateral definition

Answer 5

on the same side e.g. tumour involving right side of the brain may affect vision ipsilaterally in the right eye

Question 6

somatosensory perception pathways

Answer 6

dorsal column-medial lemniscus pathway, spinothalamic pathway

Question 7

somatosensory perception: dorsal column-medial lemniscus: pathway

Answer 7

nociceptive pain receptors → sensory neurone to spinal cord → enter grey matter (synapse onto cell bodies) → reaches spine medulla → neurone switches side of body (contralateral) → reaches thalamus → motor response comes down

Question 8

somatosensory perception: dorsal column-medial lemniscus: function and consequence if damages

Answer 8

conveys fine touch, vibration and two-point discrimination; if damaged, cannot sense changes in pressure, but if spinothalamic pathway remains intact can still feel painful consequences

Question 9

somatosensory perception: spinothalamic: pathway

Answer 9

nociceptive pain receptors → sensory neurone to spinal cord → neurone switches side of body (contralateral) → enter grey matter (synapse onto cell bodies) → reaches spine medulla → reaches thalamus → motor response comes down

Question 10

somatosensory perception: spinothalamic function

Answer 10

conveys pain and temperature sensation

Question 11

motor pathways

Answer 11

lateral corticospinal tract, vestbulospinal tract

Question 12

motor pathways: lateral corticospinal tract pathway

Answer 12

response from motor cortex → moves down spinal cord → neurone switches side of body (contralateral) → reaches effector muscle

Question 13

motor pathways: lateral corticospinal tract function

Answer 13

allows movement of limbs

Question 14

motor pathways: vestbulospinal tract pathway

Answer 14

received from just inside ear → moves down spinal cord → no neurone switching (ipsilateral - otherwise would fall over) → reaches effector muscle

Question 15

motor pathways: vestbulospinal tract function

Answer 15

microtwitches allow balance and orientation

Question 16

damage to somatomotor and/or somatosensory cortex on one side of brain, no peripheral nerve damage: effect on voluntary movement and reflexes

Answer 16

loss of voluntary movement in other side; reflex intact

Question 17

damage to somatomotor and/or somatosensory cortex on both sides of brain, no peripheral nerve damage: effect on voluntary movement and reflexes

Answer 17

loss of voluntary movement in both sides; reflex intact

Question 18

damage to peripheral and somatic nerves at that location in spinal cord

Answer 18

loss of voluntary movement, sensation and reflex activity in one limb

Question 19

damage on one side

Answer 19

damage to somatosensory and/or somatomotor cortex on other side of brain; unlikely to be spinal cord

Question 20

damage to peripheral nerve but not somatic

Answer 20

no relex action