What is blood? :
Blood, can be described as the transportation system for the body, moving substances from one part to the other. It flows through a network of channels called blood vessels of which there are two main types: arteries and veins.
Blood is made up of mostly water; some cells (the smallest units of life); substances derived from what we eat, drink, inhale and absorb through our skin; as well as substances made by the body itself.
Whilst one can live without a leg, hand, eye etc, there is no life without blood.
What makes blood red? : The entire body is made up of different types of cells e.g. skin cells, brain cells, muscle cells. The cells found in the blood are called blood cells.
There are three main types:
the red blood cells (RBC), the white blood cells (WBC) and the flat cells (also called platelets). The most numerous are the red cells and they give the blood its red colour. If blood is spun very hard and the cells settle to the bottom which is red; the top is amber, the colour of water with the dissolved substances.
What are the cells in the blood for? The red cells transport oxygen (good air) from the lungs to different parts of the body when we breathe in, and also send the carbon dioxide (bad air) produced by our substances like germs that invade our body. The flat cells help stop bleeding when there is a cut.
Where do the cells in the blood come from?:
All the blood cells are made inside our bones- the bone marrow. Each type has a limit to how long it can live. The red cells live the longest i.e. 3 months on average, the greater number of the white cells live for only days, and the flat cells for less than 2 weeks. Therefore the bone marrow is kept busy all the time making more cells to replace the dead ones.
What do the following terms means?:
Haemoglobin: this is the substances inside the red cells that give’s the red cell that gives the cell its colour and name. In the hospital laboratory, when a person’s red cell status is to be determined, it’s mainly the Haemoglobin that is measured. The short name for it is Hb. Blood group: this refers to a characteristic found on the surface of the red blood cells. It is necessary especially when one needs to be transfused with another person’s (donor) blood. The patient and the donor should be of the same or compatible type. There are 8 major types which are taken into consideration. O+, O-, A+, A-, B+, B-, AB+, AB-. All of us belong to one or the other.
Haemoglobin type: Haemoglobin in the normal adult is called A. That from the newborn child is called F. Sometimes individuals inherit other types of haemoglobin from their parents.
The commonest of these are the S and C Haemoglobin. A combination of S from one parent and another abnormal Haemoglobin from the second parent leads to Sickle Cell Disease.