Inside the eggshell is a thin membrane, almost like a skin. This membrane is porous to both air and water. Inside the membrane are the living contents of the egg, mostly a viscous liquid surrounding the nutrient-filled yolk. The whole package is neatly preserved in a tough shell capable of withstanding considerable pressure before failing.
This package of potential life could not survive without that thin membrane, because it has a unique quality. It is permeable to both water and air, but only in one direction.
This membrane allows water (and life-giving gasses like oxygen) to enter the egg in one direction only which helps maintain turgidity. Technically this is known as osmosis and it is the foundation of all life-sustaining functions in any living organism.
Differentially permeable
Technically the membrane is differentially permeable, because it allows for the movement of water in one direction only. If this did not exist, then the egg would gradually dry up (desiccate) and life would be impossible.
Technically the membrane is differentially permeable, because it allows for the movement of water in one direction only. If this did not exist, then the egg would gradually dry up (desiccate) and life would be impossible.
The water moves across what is known as an osmotic gradient, from an area of high water but low salt (known as a hypertonic solution), into an area of low water but high salt (known as a hypotonic solution). This acts as a natural pump.
This is important to understand because over the next few weeks I will be explaining more about water treatment technologies and what this means for human health.
For the time being, it is enough to know that osmosis is the foundation of all life-sustaining activities in any living organism. From the most complex human being to the most primitive single-celled bacteria or algae.
Headaches and dehydration
While drinking water is a healthy thing to do, if one drinks too much or too little water then this osmotic pressure in the body starts to do strange things.
Have you ever wondered why you get a headache if you are dehydrated? This is because the brain, consisting mostly of water, shrinks a little. The headache is a signal to drink water to regain osmotic balance.
Have you ever felt thirsty after drinking lots of water?
Again the reason is simple. The more water you drink the more turgid the cells in your body become. This triggers a mechanism in the kidneys to regain balance by shedding water through urine and excessive sweating.
This is important to understand because over the next few weeks I will be explaining more about water treatment technologies and what this means for human health.
For the time being, it is enough to know that osmosis is the foundation of all life-sustaining activities in any living organism. From the most complex human being to the most primitive single-celled bacteria or algae.
Headaches and dehydration
While drinking water is a healthy thing to do, if one drinks too much or too little water then this osmotic pressure in the body starts to do strange things.
Have you ever wondered why you get a headache if you are dehydrated? This is because the brain, consisting mostly of water, shrinks a little. The headache is a signal to drink water to regain osmotic balance.
Have you ever felt thirsty after drinking lots of water?
Again the reason is simple. The more water you drink the more turgid the cells in your body become. This triggers a mechanism in the kidneys to regain balance by shedding water through urine and excessive sweating.
The more you drink surplus to the needs of the body, the harder the kidney works, and in the process electrolytes are lost in the urine and sweat. This creates osmotic imbalance in the body, so the signal is triggered to drink more water, but this in turn sheds more salts. To restore this balance an isotonic drink is needed, which is nothing more than a fluid that contains salts and electrolytes needed for the vital biochemical functions in each cell to be restored.
