Neuro

Question 1

which 3 nuclei are important in regulating the reticular activating system during sleep

Answer 1

Lateral hypothalamus - increases RAS activity so wakefulness

Ventrolateral preoptic nucleus - decreases RAS activity

Suprachiasmatic nucleus- above optic chiasm and synchronises light levels with sleep

Question 2

which sinus ascends to join the confluence of sinuses

Answer 2

occipital sinus

Question 3

which vein joins the inferior sagittal sinus to form the straight sinus

Answer 3

great cerebral veins

Question 4

define stroke and its 2 types

Define TIA

Answer 4

a rapidly developing focal disturbance of brain function of presumed vascular origin and of >24 hours duration
—2 types: Infarction (85%) orhaemorrhage(15%)
Focal=localised

TIA= same definition but less than 24 hours

Question 5

which 2 areas work closely with the Reticular activating system?

Answer 5

ventral tegmental area

locus coeruleus

Question 6

5 metabolic causes of coma

Answer 6

Drugs 
Diabetes 
Liver/ renal failure 'the failures' 
Hypoglycaemia 
Hypercalcaemia

Question 7

Recall the 3 categories of non-metabolic causes of coma and give an example of each

Answer 7

Diffuse intracranial: meningitis
Hemisphere lesion: tumour
Brain stem: cerebellar infarct

Question 8

syringomyelia

Answer 8

Enlargement of the central canal (the space is called a syrinx) This selectively affects the spinothalamic fibres that are crossing at the level of the lesion and it does not affect fibres that have already crossed So if the enlargement of the central canal is in the region of the cervical enlargement, you could get loss of pain/temperature sensation in the arms because these fibres have to cross at that level across the central canal. However, not the legs (because those fibres would already have crossed and would be ascending in the spinothalamic tract away from the central canal)

NB this does not affect eg dorsal columns because it decussates at the medulla