Category Archives: WHAT?
176.WHAT ARE CAPILLARIES?
There are all kinds of big roads and highways connecting big cities so that food and other necessary materials can reach them. But what about the small towns and little villages? They need food and supplies, too.
The little roads and byways that reach the small towns and villages are like the capillaries in the human body. As we know, blood is pumped out of the heart to all parts of the body and the big vessels through which this blood flows are known as the arteries.
173.WHAT MAKES BLOOD CLOT?
We can’t afford to lose any blood. Even though a healthy person can lose as much as one third of all his blood and stilt live, a steady loss of blood, or loss of blood while we are sick, would be very dangerous.
Nature has protected us against this danger by giving blood the capacity to clot. If this clotting took place inside our circulatory system, it would be equally dangerous. So blood does not coagulate, or clot, when it is in contact with the-smooth walls of the blood vessels.
172.WHAT IS PLASMA?
The average person has a little over six litres of blood in his body. This blood is composed of a fluid in which various types of cells are suspended. The fluid is called plasma.
Of the total volume of the blood, about 55 per cent is made up of this plasma. It is a clear, slightly yellowish fluid. After you eat, small globules of fat become suspended in it and give it a milky appearance. This is why you are told not to eat before a blood sample is taken.
