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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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: ...
-1 votes
1 answer
174 views

Does poop have protein?

Popular health advice suggests that one shouldn't consume >30g of protein at a time (without a gap of ~3 hours, or otherwise depending on the type of protein), because only so much can be digested ...
7 votes
1 answer
268 views

Do cats ingest everything that they lick off themselves during grooming?

Cats are well-known for licking themselves clean, but what happens to all the loose hair and sand and mud and wet substances that they lick off themselves? Do they ingest everything? Do they cough up ...
4 votes
1 answer
691 views

Does food continue to stay sequential once it is inside my body?

I may be very off on many scientific details here, but I'm always all ears. As far as I understand, any food that is eaten goes to the stomach, gets broken down even further into smaller food ...
15 votes
1 answer
4k views

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 ...
0 votes
0 answers
81 views

Hepatic lobules and hepatocytes

"The hepatic lobules are the structural and functional units of the liver containing hepatic cells arranged in the form of cords. " My textbook says that the hepatic lobule is the ...
1 vote
2 answers
421 views

What is the technical term for a combination-mouth-anus?

Some organisms have a single hole that is used both for food intake and for waste excretion. Does the scientific community have a name for that hole? What is it called? Or is it simply called the ...
1 vote
1 answer
5k views

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 ...
3 votes
1 answer
564 views

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 ...
0 votes
0 answers
301 views

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) ...
8 votes
2 answers
1k views

Does human digestive system benefit from eating same kind of food consistently?

Here's the reason why I'm asking: I've heard that it takes some time for pets(cats/dogs) to adjust to a different dry feed, where the new feed has to be mixed with the old one, slowly replacing the ...
0 votes
0 answers
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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 ...
1 vote
2 answers
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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, ...
-1 votes
1 answer
300 views

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 ...
5 votes
1 answer
274 views

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 ...
2 votes
1 answer
168 views

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 ...
1 vote
1 answer
142 views

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 ...
8 votes
4 answers
419 views

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 ...
1 vote
1 answer
84 views

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?
2 votes
0 answers
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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 ...
1 vote
0 answers
213 views

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 ...
-1 votes
1 answer
391 views

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?
-1 votes
1 answer
231 views

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 ...
-1 votes
2 answers
234 views

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 ...
8 votes
1 answer
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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]...
9 votes
2 answers
27k views

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 ...
2 votes
1 answer
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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 ...
2 votes
2 answers
640 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 ...
0 votes
2 answers
90 views

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 ...
6 votes
0 answers
859 views

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 ...
40 votes
4 answers
15k views

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 ...
3 votes
1 answer
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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 ...
2 votes
0 answers
19 views

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?
1 vote
0 answers
79 views

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, ...
7 votes
1 answer
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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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46 views

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.
1 vote
1 answer
141 views

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 ...
13 votes
2 answers
27k views

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 ...
7 votes
3 answers
234 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 ...
1 vote
0 answers
35 views

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 ...
3 votes
2 answers
558 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 ...
9 votes
2 answers
255 views

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 ...
4 votes
1 answer
1k views

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....
2 votes
2 answers
3k views

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?
1 vote
1 answer
771 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 ...
6 votes
2 answers
6k views

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?
21 votes
2 answers
2k views

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 ...
2 votes
2 answers
265 views

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 ...
0 votes
3 answers
7k views

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 ...