Water reabsorption

[wannabedocta]

Where does the most water reabsorption take place?? A practice test solution says small intestine, while another source says colon

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[coffeebythelake]

Where does the most water reabsorption take place?? A practice test solution says small intestine, while another source says colon

Under normal circumstances most resorption occurs in the small intestine, but the greatest *potential* for resorption occurs in the large intestine.

 

[BloodySurgeon]

(deleted)

 

[Kaustikos]

I'd go with large intestine on the exam. The large intestine absorbs mostly water and electrolytes while the small intestine absorbs everything else that won't be excreted out. However, if you use the word reabsorption, the answer is neither one of them. It would be the distal and collecting ducts of the kidney through ADH and/or aldosterone.

Don't you just love prefixes? I've never heard of water absorption taking place mostly in the small intestine, I always thought it was the colon and Kaplan says so, as well as audio osmosis. Unless this is a trick question...or i'm studying wrongly made material.

 

[shmrshines]

Where does the most water reabsorption take place?? A practice test solution says small intestine, while another source says colon

I remember this from nursing school, so take it for what you will, but I'd go with the large intestine. This might sound gross but I always remember it like this: The longer you hold your poop the more water gets reabsorbed into your system= the harder it is coming out.(generally speaking)

 

[wannabedocta]

Yea, I had always thought the colon was the site of water reabsorption. weird.

 

[BloodySurgeon]

If I'm not missing something, the colon is part of the large intestine. And both are acceptable answers for where the water/electrolyte reabsorption is taking place.

 

[coffeebythelake]

I'd go with large intestine on the exam. The large intestine absorbs mostly water and electrolytes while the small intestine absorbs everything else that won't be excreted out. However, if you use the word reabsorption, the answer is neither one of them. It would be the distal and collecting ducts of the kidney through ADH and/or aldosterone.

The GI tract does have a significant amount of secretion and resorption, in addition to absorption.

 

[Kaustikos]

The GI tract does have a significant amount of secretion and resorption, in addition to absorption.

I f**king hate that word.

So, is it reabsorption or absorption?

 

[BloodySurgeon]

Technically reabsorption is the act or process of absorbing again, as the selective absorption by the kidneys of substances (glucose, proteins, sodium, etc.) already secreted into the renal tubules and their return to the circulating blood. The intestines are the first line of absorption (unless its something the body secreted into the lumen such as Ca2+ from the bones), therefore everything else will be reabsorption... but I see it used both ways and I don't think it really matters.

If it is going to your circulating blood its (re-)absorption

 

[tweaked17]

I hope this doesn't add to anyone's confusion, but the practice test solution is right.

This is often taught wrong or misconstrued, but the majority of water absorption (or reabsorption) occurs in the small intestine; however, the main role of the colon is concentration of excretion through water and salt reabsorption. This does not mean the majority of water is (re)absorbed here.

 

[Heyeon]

I think it is colon. Diarrhea is caused by the inability of the colon to reabsorb fluid.
This page summarizes stuff realy well: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/GITract.html

 

[BloodySurgeon]

hmm.. that makes more sense. The small intestine should be where most absorption takes place and the large intestine will play a major role in water in examples like diarrhea and constipation whenever there is a low or high osmotic pressure.

 

[BloodySurgeon]

I think it is colon. Diarrhea is caused by the inability of the colon to reabsorb fluid.
This page summarizes stuff realy well: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/GITract.html

Quote from your website:

"The large intestine receives the liquid residue after digestion and absorption are complete."

"Reabsorption of water is the chief function of the large intestine."


I agree with tweaked with his answer. I jumped into my answer because I see water absorption and immediately thought colon and I'm sure you've done the same.

And on a side note, Eikenhein is correct "The GI tract does have a significant amount of secretion and resorption, in addition to absorption" and you could say it has both absorption and reabsorption.

 

[phospho]

Quote from your website:

"The large intestine receives the liquid residue after digestion and absorption are complete."

"Reabsorption of water is the chief function of the large intestine."


I agree with tweaked with his answer. I jumped into my answer because I see water absorption and immediately thought colon and I'm sure you've done the same.

And on a side note, Eikenhein is correct "The GI tract does have a significant amount of secretion and resorption, in addition to absorption" and you could say it has both absorption and reabsorption.

thank you

 

[Zerconia2921]

Where does the most water reabsorption take place?? A practice test solution says small intestine, while another source says colon

Water gets reabsorbed in the colon ie large intestines. Small intestine depends which part is were carbs, fats, amino acids get broken down into their respectable monomers.