Blood Groups
(i) The concept of blood grouping was discovered by Karl Landsteiner. He identified blood groups A, B and O. AB blood group was recognized by Decastello and Steini.
(ii) Human blood contains certain specific substances called agglutinogens or antigens (Ag) and agglutinins or antibodies (Ab). Antigens are found on the membrane surface of RBC. Antibodies are present in blood plasma. Based on the presence or absence of antigen and antibodies human blood group is classified into four groups called A, B, AB, and O. An individual has one of the four blood groups.
(iii) 'A' group individuals: Antigen 'A' is present on the surface of RBC and antibody b (anti-b) is present in the plasma.
(iv) 'B' group individuals: Antigen 'B' is present on the surface of RBC and antibody an (anti-a) is present in the plasma.
(v) 'AB' group individuals: Antigens A and B are present on the surface of RBC and antibodies are absent in the plasma.
(vi) 'O' group individuals: No antigen A or B are absent on the surface of RBC. However, the plasma contains both antibodies 'a' and 'b' (anti a and b).
Blood donation :
(i) In blood transfusion one must consider the antigen and antibody compatibility (matching) between the donor and the person receiving blood (recipient). When an individual receives a mismatched blood group from the donor agglutination (clumping) of blood occurs in the body which leads to death.

(i) When the blood circulates twice through the heart in one complete cycle it is called double circulation.
(ii) In double circulation oxygenated blood does not mix with deoxygenated blood.

Structure of heart:
(i) Heart is a muscular pumping organ that pumps out blood into the blood vessels.
(ii) It is enclosed in a double walled sac called pericardium.
(iii) The two upper thin walled chambers are called auricles and the two thick walled chambers are called ventricles.
(iv) The chambers are separated by septum
(v) Heart contains pericardial fluid.
Working of heart:
(i) Contraction of heart is called systole and relaxation is called diastole.
(ii) When the auricles are filled with blood they are in diastole. The tricuspid and bicuspid valves remain closed. This is called atrial diastole.
(iii) When the auricles are full they contract. This leads to the opening of tricuspid and bicuspid valves. Blood from the auricles are pushed to the ventricles. This is called atrial systole.
(iv) Now the valves are closed. The ventricles contract. The deoxygenated blood from the right ventricle enters the pulmonary artery and the oxygenated blood from the left ventricle enters the aorta. This is called ventricular systole.
(v) These three events constitute the cardiac cycle.

(i) Transpiration often results in water deficit which causes injury to the plants by desiccation.
(ii) Excessive rate of transpiration leads to stunted growth of plants.

(i) Transport of respiratory gases (Oxygen and CO₂).
(ii) Transport of digested food materials to the different body cells.
(iii) Transport of hormones.
(iv) Transport of nitrogenous excretory products like ammonia, urea, and uric acid.
(v) It is involved in protection of the body and defense against diseases.
(vi) It acts as buffer and also helps in regulation of pH and body temperature.
(vii) It maintains proper water balance in the body.

Initiation and conduction of heart beat:
(i) Human heart is myogenic in nature.
(ii) Contraction is initiated by a specialised portion of the heart muscle, the sino-atrial (SA) node which is situated in the wall of the right atrium near the opening of the superior vena cava.
(iii) The Sino-atrial node acts as the 'pacemaker' of the heart because it is capable of initiating impulse which can stimulate the heart muscles to contract.
(iv) This impulse is spread by the contraction of right and the left atrial walls pushing the blood into the ventricles.
(v) The wave of contraction from SA node reaches the (AV) atrio ventricular node which is stimulated to emit an impulse of contraction spreading to the ventricular muscle through the atrioventricular bundle and the purkinje fibres.
(vi) In an healthy adult during normal resting condition systolic and diastolic blood pressure is expressed as 120mm / 80mm Hg.

WBC's are colourless and nucleated cells. Granulocytes contain granules in their cytoplasm. Agranulocytes do not contain granules in their cytoplasm, So they are classified as Granulocytes and Agranulocytes.
Granulocytes: Granulocytes contain granules in their cytoplasm. They are of three types.
(i) Neutrophils:
i) They are large in size and have a 2-7 lobed nucleus.
ii) These corpuscles form 60% - 65% of the total leucocytes.
iii) Their number are increased during infection and inflammation.
(ii) Eosinophils:
i) Eosinophils has a bilobed nucleus and constitute 2% - 3% of the total leucocytes.
ii) Their number increases during conditions of allergy and parasitic infections.
iii) It brings about detoxification of toxins.
(iii) Basophils:
i) Basophils have lobed nucleus.
ii) They form 0.5% - 1.0 % of the total leucocytes. 
iii) They release chemicals during the process of inflammation.
(iv) Agranulocytes:
i) Granules are found in the cytoplasm of these cells.
ii) The Agranulocytes are of two types:
(i) Lymphocytes:
i) These are about 20 - 25% of the total leucocytes.
ii) They produce antibodies during bacterial and viral infections.
(ii) Monocytes:
i) They are the largest of the leucocytes and are amoeboid in shape.
ii) These cells form 5 - 6% of the total leucocytes.
iii) They are phagocytic and can engulf bacteria.

Definition: Transpiration is the evaporation of water from the aerial parts of the plant especially through stomata in the leaves.
Importance of Transpiration:
(i) Creates transpirational pull for transport of water.
(ii) Supplies water for photosynthesis.
(iii) Transports minerals from soil to all parts of the plant.
(iv) Cools the surface of the leaves by evaporation.
(v) Keeps the cells turgid; hence, maintains their shape.