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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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38
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4answers
11k 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 ...
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3answers
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Are humans the only animal that requires “clean water”?

I've seen a number of animals - dogs, cats, squirrels, ducks and geese, etc drink from puddles, some of them were muddy, others had green flora growing under water. Same goes for lakes and rivers. A ...
23
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1answer
28k views

Why is coffee a laxative?

How does caffeine (or any additional agents) act as a laxative when ingested? I'm interested in the metabolic/signaling pathway.
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2answers
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 ...
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2answers
2k views

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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4answers
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What nutrients can humans absorb in the mouth?

For instance, I realise being able to absorb simple sugars in the mouth is pivotal in the rapid action of oral glucose gel. Thus I was wondering what nutrients in general can be absorbed directly ...
13
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2answers
26k 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 ...
12
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2answers
7k views

Do animals get sick from eating dirty food or eating off the floor?

Humans have very strict tradition of hygiene, such as washing hands before eating, using utensils, and in general keeping as much distance between food and dirt as possible. At the same time, most ...
12
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3answers
206 views

How do baby animals that primarily subsist on cellulose get their initial gut flora?

In the case of mammals like giraffes and koalas, is that bacteria common on the plants they eat so when a baby starts to try to stick something besides its mother's milk in its mouth, it can't digest ...
12
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2answers
309 views

Why is the microbial ecosystem of the gut so susceptible to disruption by pathogens?

From all accounts, it seems as if the Escherichia, Enterobacter, etc. that live and thrive in the human gut are pretty well entrenched. I know that these microbial populations are often analyzed as ...
11
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2answers
39k views

Does freezing microorganisms such as probiotics kill them?

Does freezing microorganisms such as probiotics kill them? If not, what is the process that allows them to "come back to life" after the temperatures are increased? As an example, lets say you ...
11
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3answers
5k views

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 ...
10
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3answers
18k views

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 ...
10
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3answers
2k views

Why do people say that trans fatty acids are bad for your health?

I've heard from several sources that trans FAs are bad for you and their consumption will lead to cardiac problems, and that they are indigestible. But I also learned from biochemistry that they are ...
9
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2answers
3k views

Are there grass or fiber eating birds?

My understanding, that may be wrong, is that cellulose/fibre has little nutritional value to many animals because it's hard to break down thus making consumption inefficient. However, Ruminating ...
9
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1answer
2k views

What influences the timing of human bowel movements in the morning?

I'm trying to understand if the timing of human bowel movements in the morning is associated with the circadian rhythm, and can thus be used to make predictions about the circadian rhythm. What ...
9
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3answers
971 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 ...
8
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1answer
410 views

What are the biochemical processes occurring when food spoils?

Let's assume for a minute that microbes themselves and their direct toxic products (i.e. endotoxins) aren't toxic to humans. Let's also discount any innate immune responses the body mounts against the ...
8
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3answers
413 views

Why are diabetic people often overweight?

I was looking at diabetes the other day, and I noticed something strange. Lower amounts of lipase are a symptom of diabetes, as is overweightness. However, since lipase is the enzyme that breaks down ...
8
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1answer
234 views

Is it the sphincter that flexes when a human pushes a bowel movement?

Of course the sphincter muscle is at the exit point. To use a toothpaste tube analogy, if I want to squeeze out some toothpaste, it does me little to no good to jostle the nozzle; I need to squeeze ...
8
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2answers
113 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 ...
8
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1answer
662 views

Why would a venus fly traps mouth that's still “chewing” die?

A venus fly trap produces leaves that act like traps for insects. A trapped insect is digested over several days. The trap then opens again to catch another insect. These traps regularly die off. ...
8
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1answer
887 views

When you have your gallbladder removed, how does it affect bile flow into your small intestine?

Cholecystectomy, or surgical removal of the gallbladder, is an extremely common operation around the world. The gallbladder is typically viewed as a storage organ for bile produced by the liver, but ...
8
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1answer
13k views

Why does anxiety cause diarrhea or constipation?

Anxiety sometimes cause diarrhea, sometimes constipation, and sometimes both. It's interesting because it seems their underlying neurophysiology is somehow different. What are underlying physiological ...
7
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4answers
6k views

Why Do Ruminants Require A Multi-Compartment Stomach To Digest Food?

Cows, camels, sheep, goats, etc being ruminants must chew their food repeatedly by regurgitating their food from their first stomach compartment and chewing their 'cud'. This then finer chewed ...
7
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2answers
479 views

Is there a biological reason for spreading food intake into breakfast-lunch-dinner?

I keep hearing over an over how humans can satisfy their entire daily caloric need in one sitting at a fast food restaurant. At the same time I'm looking at the kitchen plates, cups, etc, and they ...
7
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1answer
880 views

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: ...
7
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1answer
532 views

Cooking with sawdust

In a book about post-war Japan (Embracing Defeat, Dower) the author mentions a process for making sawdust at least partially edible, so it could be used in recipes in a 1:4 ratio with flour for ...
7
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2answers
18k 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 ...
6
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2answers
5k 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?
6
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1answer
1k views

Does inhaling glue (glue sniffing) reduce appetite?

I have heard from many homeless people that they sniff glue just to reduce appetite, as it comes cheap and is more affordable than actual food. Is this true, and if yes, why? This is totally opposite ...
6
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1answer
1k views

Excretion of small kangaroos while in the pouch

How is the excretion of small kangaroos done when they are in the pouch of their mother, fastened onto her teat? My question is what happens with the products; do they accumulate in the pouch?
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2answers
230 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 ...
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2answers
70k views

Why are my faeces black in color after eating Oreos

Why are my faeces black in colour the morning after I eat some Oreos? Day 1 : Eat a handful of Oreos & the next morning your stool is black. Day 3 : Eat a handful of cocoa flavored biscuits &...
6
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2answers
41k views

Does sour food cause sweating?

While eating sour food or candy, I start to sweat if it's sour enough. My body feels much hotter although my actual temperature is the same, my forehead starts sweating a lot and I feel like it just ...
6
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2answers
242 views

Do omnivore mammals vary food preferences based on dietary needs?

I'm wandering if mammals that can eat many different kinds of food (omnivores) vary their preference for food not only based on the availability, but also based on dietary needs? I'm looking at this ...
6
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1answer
335 views

Absorption rate of Infrequently eating animals?

Clearly, creatures such as us humans, after vastly increasing the entropy of our food, expel most of the mass that we consume. Some creatures, however, do NOT get the opportunity to eat nearly as ...
5
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1answer
3k views

How can heart disease cause dizziness after eating?

I have been reading several articles explaining dizziness after eating (see here and here), and both articles gloss over something that I found pretty remarkable. Both articles claim that "heart ...
5
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1answer
511 views

What is a lethal dose of THC?

With the oil form of THC being stronger then ever. What would happen if one was to take a stomach full of THC oil?
5
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1answer
4k views

Are nutrients absorbed in human esophagus?

Following this question regarding absorption in human oral cavity (sadly not yet fully answered), I'm curious if any nutrient absorption occurs during the descent of food through the esophagus. And ...
5
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1answer
572 views

Influence of eating at late night on sleep

I have often heard the saying that one shouldn't eat a mountain of food because blood will go to the stomach and it'll be difficult to sleep well because the stomach can't rest at night. I see that ...
5
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1answer
83 views

Enzymes and Digestion

If biological enzymes (protease,amylase,lipase etc.) just speed up the reaction (in the digestion process), then what actually digests the food?? (I'm a secondary student)
5
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1answer
1k views

Can reptiles digest grains?

As a caretaker of a turtle, I sometimes struggle understanding the logic behind the inclusion of corn, soybean, and wheat meals in reptile food, such ingredients seem truly aberrant from what a ...
5
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1answer
231 views

What is an simple way to burn glucose for visible effect?

I want to make a partially working model of the digestive system that could digest complex carbohydrates. My ultimate goal is to be able to cut up some bread, put it into the model, operate it, and ...
5
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1answer
564 views

How does the human stomach handle a mix of digested and undigested food?

As I understand it, the stomach digests the bolus into chyme and then passes the latter on to the small intestine. This process takes between 40 minutes and a few hours. However, what happens when ...
5
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1answer
807 views

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 ...
5
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1answer
3k views

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. ...
5
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1answer
373 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 ...
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2answers
2k views

By what mechanism does an obstructed bile duct cause excess fat in the stool?

By what mechanism does an obstructed bile duct (for example gallstones) cause steatorrhoea (excess fat in the stool)?
4
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2answers
699 views

Do intestinal flora have the same DNA as their host?

Please bear with me, this is not my professional field and I might be mixing things up. In an explanation why seeds won't start growing in one's intestines, the explanation given was that foreign ...