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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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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Taxonomy and morphology of marine fish

is there a relationship between taxonomy and the presence of stomach in marine fish? In other words, are stomachless fish present in only certain phylogenies or are stomachless fish scattered ...
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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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What gaseous substances do humans emit?

Other than CO₂ and Methane what other gases do humans produce or emit? For example, does skin decomposition, or aerobic respiration emit any special gases that people don't normally realize or know ...
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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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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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Digestion of Cud in a Ruminant [duplicate]

A ruminant's digestive system contains 4 chambers: The rumen, reticulum, omasum and abomasum. The food travels from the mouth to the rumen, then to the reticulum, back to the mouth, then back to 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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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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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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How does lactulose cause the removal of ammonia from the colon?

Lactulose is also used to reduce the amount of ammonia in the blood of patients with liver disease. It works by drawing ammonia from the blood into the colon where it is removed from the body. [Source]...
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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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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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595 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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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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Does variation in human gut length vary predictably with diet of ancestors?

Background: Numerous online searches, textbooks and other sources seem to pin the average length of the human gut from mouth to anus (oroanal) between about 5-10m in length. To pick a reputable ...
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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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1answer
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How is the appropriately-stratified gut microbiome acquired in organisms performing horizontal transmission?

I am studying horizontal transmission of primary symbionts in insect reproduction. This reminded me of an earlier question I had asked, in which I learned that humans analogously acquired their ...
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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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1answer
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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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1answer
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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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How does HCl not burn our stomach?

How does the digestive acid (HCl) not burn the surrounding membrane of our stomach? It digests the majority of raw food we eat but how does it stay safely in our stomach? Also, how does the stomach ...
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202 views

Is there evidence to suggest that nutrients in vitamin capsules are not as readily absorbed as the same nutrients in whole foods?

I recently fell ill with a cold, and began to take a vitamin C capsule each day to help my immune system. When I noticed no change in my condition, I began to incorporate an abundance of citrus into ...
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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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224 views

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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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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1answer
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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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what is the effect of soda water on digestion?

what is the effect of soda water on the process of digestion? As it has been seen that after drinking soda the process is increased...I just want to know that what is the chemistry behind this?
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1answer
315 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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What happens to lactic acid I eat?

Let's say I drink some Kefir Milk, what happens to the lactic acid in the Kefir Milk that has entered my digestive system?
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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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1answer
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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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2answers
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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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What part of food gives the blood red color?

Roughly, what I know is, when we eat food it goes into our: Stomach > Small Intestine > Large Intestine > Rectum. So, it just moves through a digestive pipe. What I don't understand is, what part of ...
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Is lemon water an alkalizing agent in the body?

I was recently having a discussion with someone about whether lemon water actually increases the pH of your body (by which I assume they mean the blood); their claim was that once Citric acid was ...
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1answer
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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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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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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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1answer
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Is there a link between digestion and nightmares?

A common belief is that eating too much before going to sleep can cause to have nightmares. In fact, I often experience it: I systematically have nightmares after eating too much in the evening. ...
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1answer
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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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Why does mouldy food make you sick?

Bread gets mouldy pretty quickly. My parents (both of whom are nurses) throw out a loaf of bread after a spot of mould is seen (because "if you can see one spot, it means the whole thing is covered in ...
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1answer
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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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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 ...