NBME 1 _1 question - kafe_kafka

[ArchivalUser]

Q...45 year old woman has acute coronary occlusion. Within seconds, the ischemic region shows mitochondrial swelling and depletion of glycogen granules. Which of the following metabolic events is the likly cause of the cellular changes?
1)Accumulation of fatty acids
2) ATP depletion
3)Degradation of membrane phospholipids
4)Efflux K+
5)Influx of Na+
key says answr is 3? can someone explain it..cause I thought it was
ATP depletion

[ArchivalUser]

COme on..16 lookers ...no attempts to answer my Q

[ArchivalUser]

anyone on this one?

Why the answer is not ATP depletion?
Why it could be: Degradation of membrane phospholipids?

Thanks for your time, this qs is intersting and had been posted many times, everyone ansewered ATP depletion.

Please we need your input.

Thanks

[ArchivalUser]

See in my opinion 3 would be correct if it was a reperfusion injury..but nothing in the Q stem towards that

[ArchivalUser]

I mean there is a small clue in there,depletion of glycogen granules,so if glycogen is breaking down will it not produce some Atp? How can Atp deplete also further more it's look like free radicals acting on atheromatus plaques as acute coronary occlusion occured [reason might be atherosclerosis]

[ArchivalUser]

The role of Na-K-ATPase is primarily to maintain Na and K conc. gradient accross the cell membrane.

Just to explore answer 2, 4, and 5; if ATP depleted, what will happen to Na and K?

Thanks

[ArchivalUser]

Let's Start with cell injury,

Most of the time culprit is hypoxia,leads to depletion of Atp leads to failure of Na k atpase pump[first chnage] and Na ca pump.

Cell normally was sending three naout for 2 potassium in,Now cell can't do that Na will stay in and k will stay out ,as sodium will stay in and na calcium transporter will not work so calcium will stay in too raising intracellular na and calcium ,increase na will attract water leading to edema,

Cell will try to recover [ by damage done to cell] if it is reversible, that includes
Early changes

These are reversible and include:cytoplasmic swelling and vacuolation 2 mitochondrial and endoplasmic reticulum swelling 3 clumping of nuclear chromatin.

Late changes
These are irreversible and include:1 densities in mitochondrial matrix 2 cell membrane disruption 3 nuclear shrinkage (pyknosis) 4 nuclear dissolution (karyolysis) 5 nuclear break up (karyorrhexis) 6 lysosome rupture.Death of the cell will follow the development of thelate morphological changes.
Cell death There are three main forms of cell death: autolysis,apoptosis and necrosis.

[ArchivalUser]

So ,as Atp depletes [ the first sequence that happened]

Leading To failure of Atpase pumps, Na influx and k Efflux is impossible 4 and 5 are out,along with 2

for 1 i do not it does not fit in the situation.

[ArchivalUser]

thanks goljan for the answer, I am weak in physio.
Pathophys is HY, I always screw ions exchange.

[ArchivalUser]

Do not worry my friend just give it more time you are fine and you will be fine we all forget things.