Anatomy and physiology of the blood
1. Study the composition of blood
2. Learn the blood cells
3. Draw a table and fill by the blood cells and their functions
1. Blood is bright coloured, fluid connective tissue, which consists of two main parts.
1. Plasma (60%),
2. Corpuscles (40%).
1. Plasma:
(Liquid part). It is straw coloured alkaline fluid which contains 90 to 92% water, proteins 7 to 8%,
inorganic salts 1%, glucose 0.1% and other substances in negligible amount. Glucose, amino acids,
hormones, fibrinogen and urea are other substances, while sodium chloride, potassium hydroxide,
calcium sulphate and sodium-bi-carbonate are inorganic salts present in plasma. When fibrinogen
protein is removed from plasma it is called serum.
2. Corpuscles:
(Cellular part) Corpuscles form living part of blood. There are following types of corpuscles
(a) Erythrocytes (RBCs):
Erythrocytes (Red Blood Corpuscles) are minute, biconcave circular structure, flat in the centre,
thick at the periphery. They are with a diameter of 7 microns and thickness of 1-2 micron. Mature
erythrocyte has no nucleus, no mitochondria and no ribosome. The life span is of only 120 days.
Number of erythrocytes in male is 5.5 million/mm3, in female is 4.8 million/mm3. These corpuscles
contain haemoglobin. The erythrocytes are produced in marrow of long bone such as ribs and
breast bone, but in embryo, liver and spleen also. The process of their formation is called
haemopoiesis. Erythrocytes disintegrate in spleen, liver and bone marrow, this process is called
haemolysis.
A Red coloured substance is present in Erythrocytes, it is called haemoglobin. It is Conjugated
chromoprotein. Haemoglobin forms 95% of the solids present in the RBCs. Haemoglobin has two
main parts, globin and Haem. Haem in turn; is composed of Iron and porphyrin. Each molecule of
Haemoglobin has four ferrous atoms. Porphyrin is a pigment of four pyrrol groups, it is a protein.
It is water soluble and insoluble in alcohol.
The main function of haemoglobin is oxygen carriage from lungs to body tissues and carbon
dioxide transport in blood. On breakdown it forms important bile pigments Blood gets its colour
from trillions of Erythrocytes in plasma. The blood of lobsters and other large crustaceans is blue
due to the presence of oxygen carrying pigment known as hemocyanin, as contain copper
molecules rather than iron molecules. The main function of erythrocytes is to deliver oxygen, as
they lack mitochondria they cannot use oxygen and transport full absorbed oxygen to the tissues.
(b) Leucocytes (WBCs):
These are produced in red bone marrow, lymph nodes average life is about two weeks. These are
large irregular or oval colourless nucleated structures. These corpuscles do not contain
haemoglobin. Number of leucocytes are 7000/mm3 in an adult. When number of leucocytes
increase, it is called leukaemia. There are two types of Leucocytes:
(a) Granulocytes and
(b) Agranulocytes.
Basophils, acidophils and neutrophils are the types of granulocytes. Lymphocytes and monocytes
are the types of agranulocytes. Production of anti toxins, formation of antibodies, help in fat
metabolism, phagocytic action against infecting organisms, help in tissue repair and help to
maintain plasma concentration are the main functions of leucocytes. Monocyte is the largest WBC
and smallest WBC is lymphocyte.
(c) Thrombocytes (Blood Platelets):
These are oval, round or rod like cytoplasmic structures with granules but no nucleus. Number of
platelets is 2, 50,000/mm3. These are formed in red bone marrow. Their life span is 3 to 5 days
and are destroyed mainly in the spleen. Protection of inner lining of blood vessels due to adhesive
property and initiates the process of blood clotting are the main functions of thrombocytes.
2. Blood cells, also known as hematocytes, hemocytes, or hematopoietic cells, are cells produced
mostly in the blood and are synthesized primarily in the red bone marrow.
Blood cells make up about 45% of the blood volume, while the rest (55%) is occupied by
blood plasma.
Blood contains three different types of blood cells, namely, red blood cell (erythrocytes),
white blood cell (leukocytes), and platelets.
In turn, there are three types of white blood cells—lymphocytes, monocytes, and
granulocytes—and three main types of granulocytes (neutrophils, eosinophils, and basophils).
These cells all come from the bone marrow where they develop as stem cells, followed by
their maturation into one of the three types of blood cells.
Blood cells are crucial for various functions of blood like transporting oxygen and other
essentials, protecting against antigens, and restoring tissues in the body.
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