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  #1  
Old 12-27-2011
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Default Questions on Cell biology

During a study two women one with crohns disease and one control are given oral radiolabeled lactulose solution. Appearance of radioactvity in urine is monitored and is found to be more in the woman with crohn's. Loss of functional integrity of which of the following explains this
a. adherens junction
b. basement membrane
c.desmosomes
d.gap junctions
e.tight junctions

kindly add your reasoning
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  #2  
Old 12-27-2011
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Default Question 2

Which of the following would definitively indicate irreversible injury to renal tubular cells

a.swelling of cells
b.blunting of microvilli
c.disrupted cell membrane
d.loss of granules
e. mitochondria rupture

kindly add reasoning too
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Old 12-27-2011
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Question 1 dont know

question 2 answer e.

REASON -

hallmark of reversible injury -
cytosol swelling which results in loss of microvilli and membrane blebbing
these have no prob reversible coz apply logic membrane intact ,pumps intact no electrolyte abnormality

swelling of RER results in dissociation of ribosomes and decreased protein synthesis -decreased protein synthesis still not much a prob ,cell will survive.

hallmark of irreversible injury -
plasma membrane damage- it will cause havoc in the cell .electrolyte imbalance
pumps fail and Calcium enters cell which activate caspases.

mitochondrial membrane damage always remember it will cause Cytochrome c living inside mitochondria to come out which will activate caspases and induce apoptosis. also loss of electron transport chain.

also lysosomal membrane damage release of hydrolytic enzymes

loss of granules refer to dissociation of ribosomes from RER.

disrupted cell membrane not sure what it means

but answer is e.
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  #4  
Old 12-27-2011
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Quote:
Originally Posted by indigo View Post
During a study two women one with crohns disease and one control are given oral radiolabeled lactulose solution. Appearance of radioactvity in urine is monitored and is found to be more in the woman with crohn's. Loss of functional integrity of which of the following explains this
a. adherens junction
b. basement membrane
c.desmosomes
d.gap junctions
e.tight junctions

kindly add your reasoning
I think its A. Loss of adherens junctions is responsible for multiple polyps formation. I am just taking a guess.
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Old 12-27-2011
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1) basement, cause crohns is bac. overgrowth. the other options are just types of junctions, and ive never heard of a bacteria unless its like scalded skill, which preferentially goes after a type of connection. so i would tend to lean toward basement membrane weakness for the increased permeability prolly via inflam

2) its e mitochondria.
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Old 12-27-2011
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1. basement membrane. Crohn lesion is transmural, making the barrier function of the colon/ileum mucosa defective. If one takes the oral lactulose solution and has a normal colon, the lactulose will cause diarrhea because it is non absorbable. But if the person has Crohn's, the lactulose will get directly into the vessels underneath the basement membrane and go into the circulation and appear in the urine. Hope it makes sense. Other types of cell connections are on the surface only and not important...

2.Disrupted membrane is that the ion channels can't work normally but that only disturbs the cell 's electrolyte balance and the cell can stay alive for a while. If mitochondria rupture the caspase cascade will digest all the cell contents fast.
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