100
votes
Can a person survive on blood in place of water?
Blood is not a good source of water.
1 liter of blood contains about 800 mL of water, 170 grams of protein and 2 grams of sodium (calculated from the composition of lamb blood).
When metabolized, 170 ...
- 8,124
18
votes
Can a person survive on blood in place of water?
You can drink blood of course to a minimalistic amount (eg- a few teaspoons ) and also if blood is free from pathogens. But it should always be in very small amounts and from suitable donor. Here's ...
- 559
17
votes
Accepted
What inactivates pepsin in infants?
EDIT: Thanks a lot to @abukaj for pointing out the mistake in my answer (and to @paracetamol for asking such a beautiful question). I am rewriting my answer to incorporate the (hopefully) correct ...
- 14.2k
10
votes
Can a person survive on blood in place of water?
Here is a specific account of a person surviving at sea drinking turtle blood, while eating some fish and drinking some rain water.
Several peoples have a habit of drinking raw animal blood, at least ...
7
votes
Accepted
Do humans produce rennin?
Scanning various reviews it seems that everyone who mentions the possibility of a human chymosin refers to a single paper. So for example this 2014 review has a single reference to a human chymosin:
...
- 22.9k
7
votes
Accepted
Why can't humans digest dietary fiber when we can digest starch?
"starches are held together with A bonds, dietary fibers are held together with B bonds, and the enzymes only work to break A bonds for X reason"
What you wrote here is correct. ...
- 15.3k
6
votes
Accepted
How does horse extract the energy to needs from a relatively small digestive system?
The digestive system of a horse is by no means small:
They have 15 to 21 m (50 to 70 ft) of small intestine, with a capacity of 38 to 45 L.
They have a 1.2 m (4 ft) long caecum that holds 26 to 30 L.
...
- 2,482
6
votes
Accepted
Why do gram-negative bacteria attack the digestive system more than gram-positive ones?
Gastrointestinal infections can be caused by Gram positive and negative bacteria:
Gram-positive:
Staphylococcus aureus
Clostridium difficile, botulinum and perfringens
Listeria monocytogenes
...
- 8,124
5
votes
In which organs is water that we drink absorbed into the blood?
Role of the stomach in water absorption:
The absorption of much of the ingested water from a hypotonic food already starts in the stomach due to osmotic reasons.
If we study the mechanism of secretion ...
- 1,955
5
votes
Accepted
Betaine HCl stomach pH
Betaine HCl (trimethylglycine) was present in over the counter "stomach acidifiers" but the US FDA says there is no evidence for its efficacy and has banned its use for this indication (source: US FDA)...
- 47.2k
5
votes
Can Fluoride be absorbed into the blood from within the mouth without swallowing?
Although I'm having a hard time finding a source that provides specific information on fluoride in toothpaste, this review explains that fluoride is most readily absorbed through intestinal epithelia ...
- 1,879
5
votes
Do humans produce rennin?
I think the answer is really that is isn't clear, though I only searched a bit and found mostly old papers.
It seems like people have found immunoreactivity to anti-rennin antibodies in human infants,...
- 47.2k
5
votes
Accepted
Why porifera is classified to have an incomplete digestive system although it has no organs?
An incomplete digestive system is one in which there is only one opening. In our digestive system food is taken in by one opening (our mouth), the nutrients extracted and the remains are ejected by ...
- 272
4
votes
Carbohydrates in acidic stomach
As for the digestion of fats there are two digestive enzymes active in the stomach:
Lingual lipase (produced with saliva)
Gastric lipase (produced in the stomach chief cells)
Both have activity ...
- 2,116
4
votes
Does posture matter while drinking water?
The stomach is equipped with the pyloric valve to regulate transpyloric flow to the duodenum.
Both cold and warm drinks stimulate a pattern of motility associated with retardation of transpyloric flow....
- 10.5k
4
votes
Accepted
Why are there not effective pharmaceutical treatments to prevent weight gain?
The two main factors are:
Hunger is more complex to treat than pain (more pathways, more potential targets), and I would argue against your suggestion that we are good at treating pain: despite the ...
- 47.2k
4
votes
Do sharks fart?
Excellent question. Via Southern Fried Science: According to Daniella Rabaiotti, a postdoctoral researcher at the Zoological Society of London, sand tiger sharks are the only shark known to fart.
They ...
- 226
4
votes
Accepted
Does digestion require hydrochloric acid?
Parietal cells use ion pumps to expel protons and chlorine ions into the lumen, which create the necessary acidic environment to denature pepsinogen into pepsin.
It is the low pH environment that ...
- 5,590
4
votes
Accepted
How does the stomach handle continuous eating?
First of all, the stomach releases the digested food continuously. Simply put, during digestion the pylorus regularly opens a bit so that small food particles (< 1-2mm) are able to leave the ...
- 156
4
votes
Accepted
Do cats ingest everything that they lick off themselves during grooming?
Cat licking is partially to clean themselves (including of odors that might attract predators) but is also used as a cooling mechanism (they sweat little and so use evaporation of saliva as a cooling ...
- 390
3
votes
Accepted
Absorption of pentoses in intestine
First, pentoses aren't a major source of nutrition, at least for humans. That said, pentose absorption works the same way a lot of nutrient absorption works: the "magic" of metabolism, with respect to ...
- 47.2k
3
votes
Could a mammal convert ingested dissolved CO2 to usable energy?
There isn't any biologically useful energy in CO2. In fact, humans and all other animals produce CO2 as a waste product at the end of metabolism specifically because it is low-energy. You don't need ...
- 47.2k
3
votes
Could a mammal convert ingested dissolved CO2 to usable energy?
No.
What is lacking from the question is a logical framework for the possibility suggested — that carbon dioxide can be a source of energy — and I suspect that this is because it lacks a clear ...
- 26.6k
3
votes
What are the Genes/Enzymes responsible for the supposedly stark between-individual differences in lethargy after eating starches?
The video is likely referencing alpha amylase, which is encoded in humans by AMY1A, a gene that is know to have a high level of inter-individual copy number variation. Some scientists have speculated ...
- 8,336
3
votes
What is the technical term for a combination-mouth-anus?
The mouth.
This is sometimes referred to as the hypostome (most sources, though Wikipedia disagrees). It is usually muscular.
The Pharynx.
This is the muscular part of the tube leading to the gut ...
- 2,202
2
votes
Accepted
What gaseous substances do humans emit?
There are 100+ gas phase compounds that come from humans.
Find other information about most of these families of compounds from wiki.
Full list of compounds is here
Methods and findings are here
- 10.5k
2
votes
What gaseous substances do humans emit?
A key component of body odour is the volatile thioalcohol, 3-methyl-3-sulfanylhexan-1-ol (3M3SH). The structure may be visualized as hexan-1-ol "substituted by a methyl group and a thiol group ...
- 4,780
2
votes
Can animals use the nitrogen in chitin to build proteins?
This article suggests a certain amount of chitin digestion is possible.
http://www.bio.unipd.it/agroecology/download/pdf/papers/2009/Chitin-Chitinases-Paoletti-From-Binomium-Chitnchitinase-Recent-...
2
votes
How does the human stomach handle a mix of digested and undigested food?
The regulation of emptying of food from the stomach to the duodenum takes place with the help of feedback mechanisms involving the duodenum and stomach.
Nature of the chyme which inhibits stomach ...
- 1,955
Only top scored, non community-wiki answers of a minimum length are eligible