Distribution of antigens and antibodies in different blood groups

Aneurysm the weakened regions of the wall of the artery or veins bulges to form a balloon like sac. Unruptured aneurysm may exert pressure on the adjacent tissues or may burst causing massive haemorrhage.

Varicose veins The veins are so dilated that the valves prevent back flow of blood. The veins lose their elasticity and become congested. Common sites are legs, rectalanal regions (haemorrhoids), the oesophagus and the spermatic cord.

The two types of lymphocytes are B and T cells. Both Band T cells are responsible for the immune responses of the body. B cells produce antibodies to neutralize the harmful effects of foreign substances and T cells are involved in cell mediated immunity.

(i) Eosinophils increase during certain types of parasitic infections and allergic reactions.
(ii) Eosinophils have distinctly bilobed nucleus and the lobes are joined by thin strands. They are non - phagocytic and constitute about 2 - 3% of the total WBCs.

The three types of extracellular fluids are the interstitial fluid or tissue fluid (surrounds the cell), the plasma (fluid component of the blood) and lymph.

Signals from the nervous system cause a sudden decrease in blood pressure, and the individual faints from lack of oxygen to the brain.

Heparin is an anticoagulant produced in small quantities by mast cells of connective tissue which prevents coagulation in small blood vessels

They are a type of WBC (granulocytes).
1. Basophils secrete substances such as heparin, serotonin, and histamines.
2. They are also involved in inflammatory reactions.

1. The hepatic artery brings oxygenated blood from the heart.
2. The hepatic portal vein brings blood from intestine and other abdominal organs.

1. Water potential
2. Hydrostatic pressure

1. Interstitial fluid/Tissue fluid
2. Blood
3. Lymph

(i) Right ventricular wall is thinner because the pulmonary artery transports deoxygenated blood to lungs so that much force/pressure is not needed.
(ii) Left ventricular wall is thicker because the aorta has to pump out the blood from the heart to supply oxygenated blood to all the parts of the body and needs more pressure.