Blood Connective Tissue

Blood is a fluid connective tissue that flows in the blood vessels. It forms a medium through which digested food, respiratory gases , hormones, excretory products etc.

It constitutes about 8% of the body weight. Blood consists of several cells floating in straw coloured liquid called plasma.

These cells or formed elements are Red blood cells (RBCs), White blood cells (WBCs) and Blood platelets. Formed elements constitute about 40-45 percent of the blood and plasma constitute 50-60 percent of blood. An adult man has about five to six litres of blood, while a woman, on an average has about one litre less.

Our blood consists of following of parts :-

a) Solid elements :-

Which include Red Blood Corpuscles (RBC’s), White Blood Corpuscles (WBC’s), and blood platelets.

b) Liquid elements:The plasma.

Red blood cells :These are flat and disc-like in shape with a depression in the centre. They contain the red pigment, haemoglobin. This pigment combines with oxygen to form oxyhaemoglobin that helps in transporting oxygen to all parts of the body. They are also called erythrocyte.

White blood cells:These are larger than RBCs but do not have hemoglobin. They move actively and protect the body against disease-causing microorganisms by destroying them. White blood cells are also called leukocytes. They are of two types : Granulocytes (Basophils, Neutrophils and Eosinophils) and Agranulocytes (Lymphocytes and Monocytes.

Blood platelets: They are cell fragments which are disc shaped. Normally, when one of your blood vessels is injured, you start to bleed. They help in blood clotting. Platelets, also known as thrombocytes.

Functions of Blood:

Transport of respiratory gases: blood carries oxygen from lungs to the tissues. It also carries carbon dioxide from the tissues to the lungs.

Transport of nutrients: nutrients absorbed in the small intestine enter the blood capillaries. Blood carries these nutrients and distributes them to all parts of the body.

Transport of waste products: waste products of the body, such as urea, uric acid etc, are carried by blood to the excretory organs.

Regulation of water content of cells: Blood regulates the water content of the cells. When the water content in cells increases, blood takes up the excess amount of cellular water. Blood provides water to cells when they need it.

Regulation of body temperature: increased body temperature resulting from excess respiration of a particular tissue is equalized by circulation of blood.

Defense against infection: blood protects the body against circulation.

Prevention of bleeding: clotting of blood prevents excess bleeding.

Blood helps in maintaining pH of the body.

Sample Questions

(More Questions for each concept available in Login)

Question : 1

Which of the following are correct ? (a) Blood is a fluid connective tissue that flows in the blood vessels. It forms a medium through which digested food, respiratory gases , hormones, excretory products etc. (b) The cells in the blood are Red blood cells (RBCs), White blood cells (WBCs) and Blood platelets. (c) Red blood cells are flat and disc-like in shape with a depression in the centre. They contain the red pigment, oxyhaemoglobin.
A. Only (a) and (b) is correct .	B. Only (b) and (c) is correct .	C. Only (a) and (c) is correct .	D. All of these .
Right Option : A
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