or cellular immunity, occur through the T-cell system. On exposure to an antigen, the lymphoid tissues release large numbers of activated T cells into the lymph system. These T cells pass into the general circulation. There are three main groups of T cells: (a) helper. (b) cytotoxic T cells: which attack and kill microorganisms and sometimes the body's own cells.
Organ Donation Day. About Organ Donation Day. Organ Donation Day in India is celebrated on 13th of August every year by the people, government organizations and other related professions in order to motivate normal human beings to donate the organs as well as to understand the value of organ donation in the life of an individual.
The largest pipe organ ever built, based on number of pipes, is the Boardwalk Hall Auditorium Organ in Atlantic City, New Jersey, built by the Midmer-Losh Organ Company between 1929 and 1932. The organ contains seven manuals, 449 ranks, 337 registers, and 33,114 pipes. It weighs approximately 150 tons.