Cells are the basic structural and functional unit of life. A cell not only makes up a body structure but also provide nutrients, energy, helps in the transfer of genetic materials and associated with many other functions in the body. For the normal and proper functioning of a body, every cell has to communicate with each other. Blood is a living fluid that connects various organs and organ systems with each other. Let us have a brief discussion on blood, compositions of blood, blood cells and its functions.
The higher organisms like humans level of organization are complex and so are their constituents. Mechanism of transport of fluids extends the communication between cells. In organisms, blood is the specialized fluid usually help for the communication.
Blood is a connective tissue of liquid and solid substances. More than half of the blood consists of a yellow colored liquid called plasma. It consists of salts and proteins suspended in water. About 90% of plasma is water and few percent added by proteins like albumin, globulin, and fibrinogen. Other solid constituents of blood are the blood cells namely red blood corpuscles, white blood corpuscles, and platelets. They constitute about 45 percent of total volume. These make blood thicker and viscous. Blood contributes about 6-8% of our body weight and in an average man, around 5 liters (12 pints) of blood circulates.
The function of blood does not limit the transportation of nutrients. The functions of blood include:
- Oxygen and nutrient transportation to all over the body
- Coagulation during bleeding
- Defense to fight infection
- Cleaning and removal of waste products
Types of Blood Cells
We have seen blood consist of cells known as formed elements of blood. These cells have their own functions and roles to play in the body. The blood cells which circulate all around the body are as follows:
Red blood cells (RBCs)
RBCs are the biconcave cells; also known as erythrocytes. RBCs contain the iron-rich protein called hemoglobin; give blood its red color. RBCs are most copious blood cell produced in bone marrows. Their main function is to transport oxygen from and to various tissues and organs.
White blood cells (WBCs)
Leucocytes are the colorless blood cells. They are colorless because it is devoid of hemoglobin. They further classified as granulocytes and agranulocytes. WBCs mainly contribute to immunity and defense mechanism.
Thrombocytes are specialized blood cells produced from bone marrow. Platelets come into play when there is bleeding or hemorrhage.They help in clotting and coagulation of blood. Platelets help in coagulation during a cut or wound.
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