INTRODUCTION TO HEMATOLOGY
Hematology is the branch of medicine that is concerned with the study of blood, its elements, and blood disorders.
William Hewson has been called the father of hematology for his work in advancing the knowledge of red and white blood cells, showed that it was fibrinogen and not the cells that led to coagulation, greatly advanced the knowledge of the lymphatic system in humans, fishes, and amphibians and explored the functions of the thymus and spleen.
The blood is made up of cells, fragments of cells, and dissolved biochemicals containing nutrients, oxygen, hormones, and wastes.
Blood is considered as a connective tissue due to the following reasons –
- Same embryologic origin as that of other connective tissue – mesodermal.
- Blood connects the body systems together bringing the needed oxygen, nutrients, hormones and removing out the wastes.
PHYSICAL CHARACTERISTICS OF BLOOD
Blood is a red color body fluid – the red color is due to the presence of iron-containing pigment – hemoglobin.
The intensity of red color varies with its oxygen content:-
- High oxygen content – Bright red – in arteries.
- Low oxygen content – Dark red – in veins.
Blood has a metallic taste which is mainly due to the presence of iron.
Blood is denser and more viscous than water.
pH of blood is 7.35 – 7.45.
Temperature is always slightly higher than the body’s temperature – 38°C (approx.).
The average volume of blood is –
- Adult males – 5 – 6L
- Adult females – 4 – 5L
Blood comprises 7 – 8 % of total body weight.
The specific gravity of blood is 1.050 – 1.060.
An artificial substitute for human blood has not been found.