Neuro Flashcards
what are the symptoms of spinal shock - immediately after injury?
hypotonia, hyporeflexia
priapism
atonic bladder
hypotension
lasts days to weeks
what stimulates aldosterone secretions?
ATII
indirectly via ATIII
renin
volume depletion
reduced serum sodium
how is acetylcholine metabolised at NMJ?
acetylcholinesterase
NOT pseudocholinesterases
how does sympathetic NS affect gall bladder?
causes it to relax
what is more arrhythmogenic NA or Adrenaline ?
adrenaline - due to more action on B receptor
is ATP needed for depolarisation?
no
what electrolyte changes are seen in vomitting ?
alkalosis
hypokalaemia
hypochloraemia
no sodium change - unless dehydrated can get hypernatremia
what is cerebral blood flow? in ml/100g/min
Cerebral blood flow is autoregulated to approximately 50 mL/100 g/min.
what is blood flow to carotid bodies?
Blood flow to the carotid bodies is approximately 2000 mL/100 g/min.
what is cerebral perfusion pressure in mmHg?
70-80mmHg
critical level before ischaemia is 30-40mmHg
CPP = MAP - ICP
what type of ACh receptor is found in autonomic ganglia?
nicotinic
why does CSF have reduced buffering capacity compared to plasma?
lack of protein
And lack of hco3
how does CSF compare to plasma?
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
what is the conduction velocity of fibres transmiting pain?
Ad - 5 to 30m/s - fast
C fibres - 0.5-2m/s - slow
which receptor in the skin is responsible for light touch?
Meissniers corpuscle
where are the receptors for the knee jerk reflex located?
muscle spindle within quads.
hitting the patella tendon pulls on the quads and stretches these muscle spindles.
what influences affects the knee reflex other than the monosynaptic pathway?
gamma motor neurons - affect sensitivity of the muscle spindles by changing their resting length
descending pathways - inhibitory
which fibres carry cold/ warm temperature info from peripheries?
warm - C fibres
cold - A delta
lateral spinothalamic tract
what thermoreceptors are present?
peripheral - in the skin
Deep tissue thermoreceptors - found in spinal cord, abdo organs and great veins.
which parts of the hypothalamus detect cold and hot temperature info?
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)
which group of people is brown fat more significant in?
neonates and children
What are the 2 equations to estimate the membrane potential
Nernst - single ion
Goldman hodgekin katz- multiple ions
What is the Nernst for pottasium and for sodium
K = -90
Na = + 50
