How do Fish Breathe inside Water?

            What would happen of one of us were to drown in water? We would die because of suffocation as our lungs would get filled with water. But the fish can easily survive in water. It does not live outside water for long. Have we wondered how a fish can breathe in the water while human beings cannot?

Fishes breath through gills

            Except the lungfish, all other fishes breathe by means of a special structure called gills. They do not have lungs like human beings nor do they breathe through their noses. Their process of respiration is completely different from ours. They take water in their mouths for the purpose of respiration. This water flows over the gills and comes out through the openings behind the cover of gills. The cells of the gills absorb the oxygen in water.

            Since the surface area of the gills is quite large, the amount of oxygen absorbed is also considerable. The oxygen gets mixed in the blood and is circulated throughout the whole body. That is how it purifies the blood. The carbon dioxide produced in the body is brought to the gills by the circulating blood where it gets dissolved in water and passes out of the body. In this way, the cycle of respiration in the fishes continues.

            If the water is dirty, the fishes sometimes come up to the surface of water and take air in for breathing. However, they do not use gills for this purpose, the fish is a cold blooded creature. It is also sensitive to touch, taste, smell, etc. it has different organs for these functions. Scientists have already studied more than 20,000 different species of fishes. 

What is Our Body Made of?

            Our body is made of more than 20 different chemical elements, the greatest part being oxygen. Oxygen combined with hydrogen forms water, and our body contains 65% of water.

The Human Body is composed of many different chemical elements. It may be surprising to discover that 65% of our in water

            A person weighing 100 kilograms contains approximately 65 kilograms of water. Did you know that our body has carbon equal to nearly 13 kilograms of coke? Carbon combined with hydrogen and oxygen make fats and sugars, which produce energy in the body. Our body also contains proteins, which are made of carbon, hydrogen, oxygen and nitrogen. Proteins are used for the growth and repair of the body parts.

            The body also contains calcium and phosphorus-it contains about 1.25 kilograms of calcium and enough phosphorus. Both these elements form essential parts of the bones and teeth. The body also contains sulphur, iron and other metals. But these elements are preset in traces.

How long can Man Survive Without Food?

        Like air and water, food is also essential part for all living beings. From the smallest insects to the biggest animals- all need food for their survival. So much so that even plants cannot live have long without food. Each person requires a certain amount of food daily, depending on his size, weight, age and amount of activity. Most of us feel uncomfortable, if we skip just one meal. Also, if we go without food for 12 hours or more we feel all the more lethargic.

            Energy required to do work is obtained form food we eat. Our cells and tissues suffer damage every day while doing work and need to be repaired and replaced. Food is thus needed for the growth, maintenance and development of our body. In short, we need carbohydrates, proteins, fats, vitamins, minerals and water as food for proper functioning of our body.

            Have you ever given a thought to how long we can survive without food? There are some animals that can store food in their bodies and live on stored food for a long time. It has been observed that smaller and more active animals consume more food than others, in proportion to their body weight. Warm-blooded animals use up the food stored in their body more quickly. A dog can survive without food for 20 days at the most. However, some bugs can survive without food for one full year.

            Man cannot store food in his stomach. If he misses one meal, he feels weak. Food is required to maintain the flow of blood. All constituents of blood are obtained form food. The moment blood runs low on nutritional materials, a signal goes to the brain and we start feeling hungry.

            There are a few examples of people who survived for a very long time without food. Angus Warviern of Scotland survived without food for 382 days, i.e., from June 1965 to July 1966. During this period, he took only coffee, tea, water and soda water. One South African woman survived for 102 days on water and soda water. Stefan Taylor of New Zealand survived for 40 days in 1970 on a daily intake of just one glass of water. There are many such examples. Such people are endowed with exceptional power. A common man can, at the most, survive without food for a week.