19
votes
Accepted
How deep under water can humans open their naked eyes without damaging them?
Crushing damage from pressure occurs due to pressure differences. Imagine you have a rigid container. If you have equal gas pressure inside and outside, the pressure acts on just the walls and the ...
- 41.2k
13
votes
How deep under water can humans open their naked eyes without damaging them?
Goggles do not, cannot, protect eyes from pressure. The pressure on both sides of goggles should be nominally the same. In fact, divers tend to use a mask, which communicates with the nose, to be able ...
- 231
9
votes
How deep under water can humans open their naked eyes without damaging them?
Currently the record for the deepest dive wearing scuba equipment is 332.35m. The descent took only 15 minutes while the ascent lasted 13 hours 35 minutes.
Liquids do not compress, so the sinuses, ...
- 9,322
7
votes
Accepted
Can brain damage caused by physical injury affect the social behaviour of a person?
Socialization is a cognitive and executive brain based function that requires higher level thinking mechanisms usually dependent on the prefrontal coretex. A lot of social cues we obtain from our ...
- 534
5
votes
What's a mouth ulcer/canker sore "made of", and why do they develop?
The redden area around the grayish-white indentation of the canker sore isn't filled with anything. This circular area is simply inflamed. The grayish-white area in the center is not filled with puss ...
- 2,177
4
votes
Why does it hurt when water touches cuts?
Water changes the local ionic concentrations and therefore induces an electric
signal at exposed neuron membranes.Oil is used to prevent entrance of water to the cut because it is hydrophobic i.e. ...
4
votes
Can skin be removed and replaced so that it maintains its original cellular structure?
As pertains to skin, no. As pertains to your other fears, that's a different question.
Every cut that extends into the dermis significantly (and to remove skin, it must include the dermis) will leave ...
- 24.7k
3
votes
Why does it hurt when water touches cuts?
It's a phenomenon called cutaneous hyperalgesia in which non-noxious stimulus like water cause pain. The Mechanism behind that phenomenon is the accumulation of pain-producing factors like (substance ...
- 31
3
votes
Accepted
If oxygen deficiency is bad even for a short while, why do people swim?
In this paper the authors measured decrease of arterial blood oxygen saturation in healthy and patients with sleep apnae (this latter part is not really relevant only the measurements in healthy ...
- 3,098
2
votes
"Next generation" brain scanners, can they detect CTE?
I do not know the details of the innovation, but it's based on MEG. MEG is a complementary technique similar to EEG, sesitive to magnetic fields instead of electrical fields (hence the 'M' in place of ...
- 3,045
2
votes
Does copper exacerbate wounds?
Excess copper in the body can be toxic but I'm not sure a copper blade would be especially toxic unless it was coated with something else or it remained in the wound. Copper can be acutely toxic when ...
- 3,318
2
votes
Accepted
Saving lives by "conjoining" people
As mentioned in other answers, the problems with accomplishing this are manifold but primarily relate to the immune systems of the donors and recipient. While it may seem like anastomatizing the ...
- 1,763
2
votes
Accepted
If a hand was suddenly chopped off while holding something, would the severed hand still hold a grip?
(Disclaimer: I have no personal or medical experience of cutting off hands, or any other body parts, so this is purely theoretical.)
It seems unlikely, since most of the muscles that provide the ...
- 3,633
2
votes
Accepted
I hit an area of my elbow and had a burning sensation throughout my hand
It's often referred to as hitting your funny bone:
Heres one reference on the subject:
https://www.huffpost.com/entry/hitting-your-funny-bone-i_b_12201698
and here is another:
https://www.mentalfloss....
- 9,322
1
vote
Accepted
Is there a physiological reason why direct lightning strikes are not lethal for everyone or does it all come down to dumb luck?
Is there a physiological reason why direct lightning strikes are not lethal for everyone or does it all come down to dumb luck?
To be lethal a lighting strike has to do enough damage to a critical ...
- 952
1
vote
Why do we get scars?
Scars are fibrous tissue that is left after an injury. The body does its best to fix a body part after an injury and scars are their best attempt at doing so. It would be pleasant to think we could ...
- 67.9k
1
vote
Where does the exudate comes from during inflammation?
exsudates almost exclusively come from the capillary compartment. If you think about the structure of the vessels, this appears logical.
The capillary compartment :
has vessels only several microns ...
- 1,410
1
vote
Is a stab wound to the back lethal?
Check out the sources of Wikipedia article: the mortality rate is up to 4%.
The main causes of "immediate" death in penetrating trauma are shock (low blood pressure due to external/internal ...
- 5,670
1
vote
Why Is The Toughness Of Skin Different On Different Parts Of The Body?
There are different receptors and different forces at play here.
Skin thickness depends primarily on frictional forces and is determined by the thickness of the epidermis, which is made up of 5 layers ...
- 176
Only top scored, non community-wiki answers of a minimum length are eligible