Review 3 Flashcards
why does the combined pill increase the risk of thrombosis
more than physiological amount of oestrogen affects coagulation proteins
affects 80% - some more than others
eg factor 8, 10, 12 - make more active
protein S inhibited
general swing to thrombosis by 2 mechanisms
reduction in fibrinolytic activity - ability to degrade clot is reduced
this is also seen in pregnancy
when a patient has sympathoexcitation because of an adrenal tumour causing myocardial ischemia - what is causing the ischemia
decreased diastolic time
because:
coronary arteries are on the outside and brach inwards
contraction compresses these arteries
heart only gets O2 in diastole when bigger perfusion pressure = flow to myocytes.
Tumour = adrenaline = HR faster - blood has got no time to get into the myocardium = ischemia
also working harder so has a higher O2 demand anyway, more anaerobic
this is an organ wide issue
(small perfusion pressure - because time has gone down) n
explain how an intraaortic balloon pump works
inflated in diastole less than 100% otherwise would damage the vessel wall when it contracted and restrict blood flow - when blood is in aorta it stretches it but then it recoils when you have pulsatile but continuous flow with pressure 120/80 reduces afterload increases coronary artery perfusion increases deflate in systole - pressure is reduced
why is the position of the balloon important
not below renal arteries
not in arch - don’t want to risk blood flow to the head
why is helium used in balloons
low density
effect of balloon pumps being insoluble in water
if the balloon bursts causes gaseous embolism = stroke
have to put the person upside down to reduce the chance of stroke - then take them to a decompressor at 50m depth - compress bubbles and help them leave the body
what is the pressure and velocity change in an aneurysm compared to before the aneurysm
increase in pressure in aneurysm
reduction in velocity
what is in the lethal injection
painkiller
aesthetic
cardioplegic
what is used is the cardioplegic
high levels of K+
why is K+ used in the lethal injection
it arrests the heart
Ca would work - but arrest in systole so couldn’t operate
could use Na but would need a lot more because extra cell vol of Na is already high
effect of balloon on pressure
reduce diastolic pressure but increase systolic pressure
decreased diastolic pressure is what helps with perfusion
