spinal chord and basic reflexes

Question 1

reflex

Answer 1

an automated unlearned reaction to a stimulus

Question 2

spinal cord

Answer 2

internal- grey matter inside, white matter outside

Question 3

the central canal

Answer 3

a continuation of the ventricular system in the brain

Question 4

grey matter differentiation

Answer 4

dorsal horn, lateral horn, ventral horn

Question 5

white matter differentiation

Answer 5

posterior funiculus, lateral funiculus, anterior funiculus

Question 6

afferent neurons

Answer 6

travelling towards CNS, sensory

Question 7

efferent neurons

Answer 7

travelling away from CNS, motor

Question 8

the meninges

Answer 8

outermost is the dura mater, delicate arachnoid-middle, pia mater surrounds brain and spinal cord.

the space between the arachnoid and pia is the subarachnoid space, contains blood vessels and cerebro spinal fluid [CSF]

Question 9

the meninges around the spine

Answer 9

The dura blends with the epineurium of the existing spinal nerves.
The pia eventually continues [after enveloping the spinal cord] to form a terminal strand-the filium termalis.
The arachnoid lines the dura until itself ends within the sacrum.
The cord ends before the covering- CSF can be obtained through lumbar puncture below this height with no chance of hitting the spinal cord.

Question 10

lumbar puncture indications

Answer 10

query meningitis?
Subarachnoid haemorrhage- LP is indicated only for those cases of SAH that are negative on CT scan. Should be performed 6 hours after the onset of bleeding to ensure that blood will have reached the lumbar region.
Also for:
inflammatory conditions:
Guillain Barre syndrome
systemic lupus erythematosus
sarcoidosis
Behcets syndrome
multiple sclerosis
malignant disease:
lymphoma
leukaemia
paraneoplastic disorders

Question 11

the vertebrae that make up the vertebral column

Answer 11

cervical= 7 vertebrae
thoracic= 12
lumbar=5
sacrum= 5 [fused]
coccyx [3-4 fused]

Question 12

spinal drug administration

Answer 12

extradural/epidural: only acts locally.

spinal- (subarachnoid) drug diffuses throughout CNS.

Question 13

The dorsal columns of the white matter

Answer 13

• ascending tracts.
• Gracile (hindlimb)
• cuneate (forelimb)
• > light touch, vibration sense, proprioception

Question 14

the spino-cerebellar columns of the white matter

Answer 14

• ascending tracts.
• dorsal
• ventral.
  carries information transmitted from muscle spindles, mechanoreceptors such as golgi tendon organs and tactile receptors, these are relayed to the cerebellum for the control of posture and the control of movement. 4 pathways considered to be involved in the process- 2 carry information from upper limbs and 2 from lower limbs. The spinocerebellar system consists of a sequence of 2 neurones whose cell bodies of origin mostly lie in the base of the dorsal horn, some fibres ascent contralaterally.

Question 15

the spinothalamic tracts of the white matter

Answer 15

• ascending tracts.
• lateral
  -anterior.
  transmits information to the thalamus about pain, temperature, itch, tickle, deep touch, and orgasm

Question 16

decussation comparison

Answer 16

contralateral- opposite side

ipsilateral- same side.