Neuro

Question 1

what are the symptoms of spinal shock - immediately after injury?

Answer 1

hypotonia, hyporeflexia
priapism
atonic bladder
hypotension

lasts days to weeks

Question 2

what stimulates aldosterone secretions?

Answer 2

ATII

indirectly via ATIII
renin
volume depletion
reduced serum sodium

Question 3

how is acetylcholine metabolised at NMJ?

Answer 3

acetylcholinesterase
NOT pseudocholinesterases

Question 4

how does sympathetic NS affect gall bladder?

Answer 4

causes it to relax

Question 5

what is more arrhythmogenic NA or Adrenaline ?

Answer 5

adrenaline - due to more action on B receptor

Question 6

is ATP needed for depolarisation?

Answer 6

no

Question 7

what electrolyte changes are seen in vomitting ?

Answer 7

alkalosis
hypokalaemia
hypochloraemia

no sodium change - unless dehydrated can get hypernatremia

Question 8

what is cerebral blood flow? in ml/100g/min

Answer 8

Cerebral blood flow is autoregulated to approximately 50 mL/100 g/min.

Question 9

what is blood flow to carotid bodies?

Answer 9

Blood flow to the carotid bodies is approximately 2000 mL/100 g/min.

Question 10

what is cerebral perfusion pressure in mmHg?

Answer 10

70-80mmHg
critical level before ischaemia is 30-40mmHg

CPP = MAP - ICP

Question 11

what type of ACh receptor is found in autonomic ganglia?

Answer 11

nicotinic

Question 12

why does CSF have reduced buffering capacity compared to plasma?

Answer 12

lack of protein
And lack of hco3

Question 13

how does CSF compare to plasma?

Answer 13

slightly more acidic - pH 7.3
slightly more chloride
less protein
same glucose or slightly less 2/3rd the value of plasma
same Na and K

Question 14

what is the conduction velocity of fibres transmiting pain?

Answer 14

Ad - 5 to 30m/s - fast
C fibres - 0.5-2m/s - slow

Question 15

which receptor in the skin is responsible for light touch?

Answer 15

Meissniers corpuscle

Question 16

where are the receptors for the knee jerk reflex located?

Answer 16

muscle spindle within quads.

hitting the patella tendon pulls on the quads and stretches these muscle spindles.

Question 17

what influences affects the knee reflex other than the monosynaptic pathway?

Answer 17

gamma motor neurons - affect sensitivity of the muscle spindles by changing their resting length

descending pathways - inhibitory

Question 18

which fibres carry cold/ warm temperature info from peripheries?

Answer 18

warm - C fibres
cold - A delta

lateral spinothalamic tract

Question 19

what thermoreceptors are present?

Answer 19

peripheral - in the skin
Deep tissue thermoreceptors - found in spinal cord, abdo organs and great veins.

Question 20

which parts of the hypothalamus detect cold and hot temperature info?

Answer 20

pre optic hypothalamus = detects rise in temp and outputs include vasodilation, sweating and inhibition of posterior hypothalamus

posterior hypothalamus = detects drop in temp and triggers shivering and chemical thermogenesis (uncoupling of oxidative phosphorylation in brown fat)

Question 21

which group of people is brown fat more significant in?

Answer 21

neonates and children

Question 22

What are the 2 equations to estimate the membrane potential

Answer 22

Nernst - single ion
Goldman hodgekin katz- multiple ions

Question 23

What is the Nernst for pottasium and for sodium

Answer 23

K = -90
Na = + 50