Class 11 Biology — Chapter 15: BODY FLUIDS AND CIRCULATION

Understand that blood is a special connective tissue composed of a fluid matrix called plasma and formed elements. Students should know the components of plasma, including water, major proteins (fibrinogen, globulins, albumins) and their functions, and what constitutes serum.

Learn about the characteristics of Red Blood Cells (RBCs), including their abundance, biconcave shape, lack of a nucleus in mammals, and their primary function in transporting respiratory gases via the iron-containing protein, haemoglobin. Also, know their lifespan and site of destruction (spleen).

Differentiate between the types of White Blood Cells (WBCs): granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes). Understand their respective roles in the body's defense mechanisms. Also, understand the function of platelets (thrombocytes) in blood coagulation.

Understand the basis of the ABO blood grouping system, which involves the presence or absence of A and B antigens on RBCs and anti-A or anti-B antibodies in the plasma. This includes identifying blood types, principles of safe blood transfusion, and the concepts of 'universal donor' (O group) and 'universal recipient' (AB group).

Explain the Rh blood group system based on the presence (Rh+ve) or absence (Rh-ve) of the Rh antigen. Students must understand the clinical significance of Rh incompatibility, particularly the condition of erythroblastosis foetalis that can occur between an Rh-ve mother and an Rh+ve fetus.

Describe the mechanism of blood clotting (coagulation), which is a cascade process initiated by injury. This includes understanding the conversion of inactive fibrinogen to fibrin by thrombin, the role of thrombokinase, platelets, and the importance of Calcium ions in this process.

Understand the formation of interstitial or tissue fluid from blood in capillaries. Students should know the composition of lymph and its key functions, including the exchange of substances, transport of nutrients and hormones, immune responses by lymphocytes, and absorption of fats in the lacteals.

Differentiate between open and closed circulatory systems. Students should be able to provide examples of organisms for each type (e.g., arthropods for open; annelids and chordates for closed) and understand the advantages of a closed system, such as more precise regulation of blood flow.