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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Is raw meat or raw vegetables easier for humans to digest?

Which one is easier for a human digestive system to digest, raw meat or raw vegetables? I have heard some of my friends who say that raw (or uncooked) meat is easier to digest than raw (or uncooked) ...
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What are the possible causes of Lactase persistence?

Lactase enzyme which is responsible for the digestion lactose (a disaccharide milk sugar) normally its production decreases when a young mammal is weaned but mostly Humens continue to produce this ...
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Why porifera is classified to have an incomplete digestive system although it has no organs?

Why are we using the term "incomplete" for digestive system only? We could have also said that for circulatory system that it is either incomplete or present as a simple system. What I mean ...
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What are the Genes/Enzymes responsible for the supposedly stark between-individual differences in lethargy after eating starches?

Andrew Huberman claims in one if his podcasts episodes that: [...] because starches cause the release of serotonin in the brain and lend themselves to a state of sleepiness. Now, I should mention ...
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What is inside digestive system while it's empty?

Up to this point, all my life I assumed that stomach and intestines are filled with air. I got this impression from all the anatomic drawings in schoolbooks and encyclopedias that show empty stomach ...
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Why can't humans digest dietary fiber when we can digest starch?

So, I can see that there's a couple of questions touching on this subject already, but none of them answer the aspect that I'm curious about: Dietary fiber is a polymer composed of multiple starch ...
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Is it true that the cells of large and small intestines cannot secrete digestive enzymes into the GI tract in the same way as the stomach does?

When I read about the intestines, I usually see the word 'release' instead of 'secretion'. Secretions of the small intestine, for example, occur from two types of histological structures: Brunners ...
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Herbivore digestive System

Why do Herbivores have many different types of digestive Systems? for example a Rabbit has a mono-gastric Digestive system and a hippopotamus has a pseudo ruminant digestive system but they are both ...
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What is the function of human Trypsin Inhibitor if trypsin is secreted in the inactive form of Trypsinogen? [closed]

I was reading about pancreatic digestive enzymes in a Textbook of Medical Physiology and I came across Trypsin Inhibitor. The text stated that: It is important that the proteolytic enzymes of the ...
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Parasympathetic effects on digestive tract - motility versus absorption

The parasympathetic nervous system's purpose is often referred to as "rest and digest." As part of this purpose, parasympathetic innervation increases motility in the digestive tract to move ...
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Why humans didn't evolve to safely consume rotten food? [duplicate]

I'm not a biology person at all so please forgive me if my question is silly. I was just wondering that why didn't evolution cause us to digest, without issues decomposed food?
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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? [closed]

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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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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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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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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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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