What damage does sea water do to the skin?

As we all know, more than 70% of our earth is water, and this water is not fresh water, but sea water. Because the composition of seawater is quite special, it cannot be directly used as drinking water, which is somewhat regrettable. People who live by the sea all year round know that even if they go to the sea to play, they cannot let their bodies come into contact with sea water for a long time. So, what are the harms of sea water to the skin?

First you need to understand the phenomenon of penetration. In nature, plants absorb water from the soil through the semipermeable membrane of their roots; if you sprinkle table salt or concentrated brine on fresh vegetables, the water in the vegetables will seep out; the exchange of water between plasma and red blood cells, and between tissue fluid and cells in the human body are all osmosis phenomena.

There is a rule in the osmosis phenomenon. If two salt waters with different concentrations are separated by a semipermeable membrane, water molecules will always penetrate from the dilute salt water side to the concentrated salt water until the concentrations on both sides are equal.

Secondly, you need to know that the human body's tissue fluid and cells contain table salt, which is sodium chloride. Under normal circumstances, the solution inside the cells and the plasma outside the cells must maintain a certain concentration.

The salt content in seawater is usually more than three times that in human body fluids. If people drink seawater, the salt content in their body will increase greatly. In order to achieve equal concentration inside and outside the cell, water will seep out of the cell, causing cellular dehydration. Therefore, sea water cannot be drunk directly.

The same situation actually exists during infusion. If the infused saline is too concentrated, the concentration of plasma will increase after the infusion, and the water in the blood cells will permeate outward, causing cell dehydration. If the injected saline solution is too dilute, the water in the plasma will penetrate into the blood cells with higher concentration. The result will be that blood cells will swell or even rupture, resulting in hemolysis.

The above introduces some of the hazards of seawater to the human body. I believe everyone has already understood it. In fact, due to the density of seawater, after it enters the human body, it not only cannot supply water to the body tissues, but on the contrary it takes away the water in the human body and excretes it with urine. It not only fails to quench thirst, but also causes the body to lose water faster. However, if you are at sea, in order to save fresh water, you can mix it with seawater in a certain proportion.