Questions tagged [digestive-system]

Organs that play a role in digestion and/or absorption of nutrients: breaking down of food into smaller components that can be absorbed and used as for sources of energy, cellular/tissue building blocks, or cofactors for vital biochemical reactions.

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27 views

Diarrhea / constipation: why are they associated with failure of the large intestine (and not the small intestine) to reabsorb water?

When I see reference to diarrhea or constipation, it's almost always in reference to the under- or over-reabsorption of water, respectively, in the large intestine. However, if the large intestine ...
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Do identical twins have the same metabolism rate at birth?

Will monozygotic twins defecate at the same time if fed at the same time during the first weeks of life? They should have the same genetics (and epigenetics) since they are monozygotic and the same ...
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Are intestinal and pancreatic lipases different?

For explaining the action pancreatic lipase, my book wrote this equation:- $$fat\space particles + lipase\rightarrow fatty\space acid + glycerol + lipase$$ But for intestinal lipase, my book has a ...
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Gastric and intestinal gas exchange

A very long time ago, I happened across research into using an oxygenated liquid in the stomach and or intestinal cavity. I wondered what further results came about of that research, and am having ...
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Do lack of sleep affects the process of digestion? [closed]

Many times due to lack of sleep I felt discomfort in digestive tract.Why did it happen?Do lack of sleep affects the process of digestion?
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Why do vertebrates have an oesophagus?

As far as I know, the oesophagus in vertebrates has no digestive or absorptive function. It is simply a conduit from the mouth to more distal parts of the gastrointestinal tract. Why have it at all, ...
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Why is gastrin not acing paracrine manner primarily, when it acts mainly on cells nearby its release?

Gastrin is released by G cells and stimulates Parietal cells to secrete hydrochloric acid. Why is it not acting in a paracrine fashion instead of endocrine?
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Why do gram-negative bacteria attack the digestive system more than gram-positive ones?

I was researching for a biology project on the subject of contagious infections of the digestive system (mainly the intestines) and almost all of the bacteria that came up (E.coli, Shigella, Cholera, ...
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Is the “first pass effect” diminished more by some foods than others?

This effect and its considerations are fairly well known but it's never been clear to me whether it's a greater consideration with some types of food than others.
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How are proteins reused in the body? [duplicate]

Part of what we eat are proteins, and our body is in part build of proteins. Are the proteins of the body build based on proteins in food at all? Are proteins in food directly reused in the body, or ...
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Why are nutrients from food absorbed more efficiently? [duplicate]

It seems to be common knowledge that micronutrients such as vitamins are more easily absorbed by your body when in your diet versus supplements such as pills. I am wondering what the reasons for this ...
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Can undigested food proteins enter the bloodstream? [duplicate]

I know that food proteins in our digestive system are denaturated and broken down into amino acids or very small peptides that are then absorbed in the small intestine. If some proteins stay ...
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Does body absorb nutrients less efficiently if we ingest the same amount at the same time, opposed to spreading over a larger period?

I would like to understand if ingesting a certain amount of nutrients will result in different absorption from my body, depending on whether I ingest that amount spread over time or everything at once....
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212 views

Are casein proteins in UHT milk digestable for infants or toddlers?

As a novice cheesemaker, I have read that Ultra High Temperature prosessed milk is unsuitable for cheesemaking, as casein proteins are denatured and cannot be curdled with rennet. I have verified that ...
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Reducing Ammonia Levels in Body through Bowel Movements Only

Can high ammonia levels in body be reduced solely through repeated bowel movements (4-5 per day), i.e., WITHOUT the use of Lactulose?
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How does the stomach handle continuous eating?

In biology class, we learned this familiar story: Food enters the stomach, the stomach churns it with acid and enzymes, and then, somehow, the stomach senses when the stew is ready and releases it ...
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Can a person survive on blood in place of water?

This question: Can you get enough water by eating only fish? asks if a person could survive on fish alone. Can a person survive on fish and/ or blood alone of any species if stuck at sea or animal ...
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Does digestion require hydrochloric acid?

Would our digestion function any differently if we secreted something else, like sulfuric or nitric acid, instead? I'd assume an acidic environment may be required, but not sure if chloride is also ...
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How can we usually “trust a fart” not to be liquid or solid?

Jack Nicholson's character Edward Cole in the movie The Bucket List said ...and never trust a fart, and a search for Al Roker leakage White House will clear up any doubts what that's all about. How ...
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How does the symbiotic bacteria reaches a human caecum

My thought on this matter is that we have got a very high pH of about 1.8 in our stomach.So,most of bacteria who came in through food or just open mouth should be killed by it.So,how does a bacterial ...
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Do sharks fart?

My son is 5 and I'm encouraging him to be curious and ask questions of the world around him. He asked if sharks fart and how does it smell? He feels that it would smell of fish and be disgusting. He ...
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Does pepsin enzyme digest other enzymes like other pepsin molecules

Pepsin digests proteins, as we know, but can it digest other enzymes that are actually made up of proteins, like digesting other pepsin molecules?
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Could a mammal convert ingested dissolved CO2 to usable energy?

I'm trying to find out if it's possible that a mammal could orally ingest dissolved CO2 and convert it to energy for body heat, organ function, etc. Unfortunately, most of the scientific sources I've ...
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Muscle layers of pharynx and gi tract

Why does pharynx have an internal longitudinal muscle layer and external circular muscle layer, while oesophagus and the rest of gastrointestinal tract have inner circular and outer longitudinal ...
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Can the human gut work with other type of gut bacteria?

I was wondering if the human body would be capable of functioning with, say, cellulolytic bacteria in their gut (instead of or in addition of their current bacteria), like that of ruminants and if ...
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194 views

Do cows chew in a preferential chirality?

One of the enduring myths in molecular physics, when talking about chirality as pertains the existence of enantiomers and the differences between them, is that the way cows chew is also chiral, i.e. ...
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Epidermal layer and muscle wall of colon?

First of all,I wanted to ask that whether epidermis is present in colon ? And if yes than how is muscle wall present with respect to epidermis. Can anyone give me a pic that has both the epidermis and ...
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Nonpancreatic digestion of tryglicerides

In an answer about coconut oil I can read the digestion of coconut oil does not involve in the Pancreatic digestive enzyme system In both primary and secondary school I have learned that fat needs ...
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How exactly is casein digested?

I mean it seems first step is rennin or pepsin digestion in stomach - then what happens with remaining peptides? I am interested in the whole process from casein to amino acids. Is there brush border ...
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Can gut flora affect what we can eat and what we cannot?

Back many years ago, I've read a mushroom guidebook, which I don't have anymore. I was unable to find the name of a particular mushroom. The book comprises listing of edible and poisonous mushroom ...
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What can pass through the intestinal membranes?

As I understand it, most substances need help to pass through the walls of the intestines. For example, in hepatic recirculation (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781307/) bile salts are ...
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447 views

Why does enteral carbohydrate yield higher energy than parenteral?

The following is written in a well-known textbook of surgery: Each gram of enteric carbohydrate provides 4.0 kilocalories (kcal) of energy. Parenterally administered carbohydrates (eg, ...
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Sensitivity Along Digestive Tract [closed]

Suppose you swallowed a little capsule with a blunt poker which had some impulse of force applied every few seconds. What would be the sensitivity ordering (of lips, mouth, throat, esophagus, stomach,...
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Do humans produce rennin?

At school, we've been taught that human infants produce rennin/chymosin (which aids in the digestion of milk). More specifically, it is the peptic cells in the stomach which secrete prorennin, the ...
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Can Fluoride be absorbed into the blood from within the mouth without swallowing?

I'm having a discussion with somebody regarding Fluoride usage. I told him that even if he doesn't like the idea of ingesting it, brushing and spitting it out will do you no harm. He then said this: ...
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Why do humans cook animal meat

Why do humans "need" to cook animal meat? It seems there's an aspect of safety to it: are other animals (eg, house cats, dogs) not vulnerable to the same diseases we get from modern food processing ...
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756 views

Which cells produce HCl produced in stomach? Don't these cells get destroyed by HCl?

Which cells produce HCl produced in the stomach? Or is HCl produced due to the translation of proteins. Don't these cells get destroyed by HCl?
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Bicarbonate concentration in saliva

From the picture it can be seen that Bicarbonate is secreted into lumen of duct of salivary glands by exchanging Cl- ions. So if flow rate of saliva is increased then its obvious that less Cl- is ...
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In which organs is water that we drink absorbed into the blood?

From biology classes I remember that water from food we eat is mostly 'sucked in' (absorbed into blood) in the colon. I guess the same is true for water we drink. But if I eat something, it will reach ...
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789 views

How are micelles formed from the byproducts of emulsification in fat digestion?

It is known that fat droplets are made into emulsion droplets via the addition of bile salts. It is then said that the emulsion droplets are made into micelles through some sort of lipase, which can ...
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570 views

Carbohydrates in acidic stomach

How does the acidic environment in the stomach affect carbohydrate and fast digestion? Does it aid, impede or remain neutral in their digestive process? Or do the carbohydrates, fats and proteins ...
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1k views

Does the pyloric sphincter contract after ingesting only liquid?

At university, I was told by one of my fellow students that the reason why eating before going on an alcohol laden night out was a good idea, was because the pyloric sphincter contracted once food was ...
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Does posture matter while drinking water?

I have heard a lot of people (where I am from, India) say that one must drink water sitting, not standing. Recently, I also came across a video that said the same thing (link). The reason given is ...
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Betaine HCl stomach pH

It seems betaine HCL is often recommended for those suffering from "low stomach acid" -- which, as I understand, is having too high stomach pH for proper digestion (especially for proteolysis via ...
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What inactivates pepsin in infants?

In infants, rennin helps in digestion of milk. Pepsin is also present in their stomach. Why do infants need rennin for milk digestion, at the first place? Why does pepsin not act on the milk ...
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What happens to the enzymes produced by the digestive system?

Our digestive system produces a lot of enzymes and they help to catabolize the food, and after completing their work are they excreted out or as they are also made up of proteins are they catabolized ...
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73 views

Why are there not effective pharmaceutical treatments to prevent weight gain?

Hunger is caused by signals from the brain, so is there a way to suppress the signal of hunger in the same way we suppress the signal of pain with painkillers? If people felt less hungry, they would ...
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Eating possibly spoiled food in the fasted state - is it considered protective against the potential harm?

It is a known fact that the acidic environment in the stomach serves several purposes, such as providing suitable conditions for primary chemical digestion of food molecules and protection from ...
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How is chewing gum processed?

There is the common belief that Chewing gum takes 7 years to digest But is this actually true? Does it really stick to your intestines for 7 years, or is it processed like all foods, except it isn'...
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464 views

Why does a stomach come before the gizzard in birds?

Since the gizzard is for mechanical digestion, shouldn't that happen before the stomach digests the food with acids? (to make the morsels smaller)