Every day is a new battle for the human body as microscopic intruders try to muscle their way in. What specialized cells and organs are there to resist them? This program clearly and concisely maps out the complicated human immune system, explaining both how it keeps the body healthy and what happens to the body if it malfunctions—or, even worse, if it shuts down completely. Beginning with the body’s nonspecific defenses, composed of the skin, tears, mucus, saliva, and stomach acid, the program then digs into the details of the specific defenses: the lymphatic system, the thymus gland, the spleen, and bone marrow. Three distinct types of white blood cells are classified, and the complexities of the humoral and cell-mediated immune responses are carefully sorted out. The program also describes a number of problems with the human immune system, running the gamut from allergies to AIDS. Vaccines and antibiotics are also discussed, as is the growing danger of bacterial resistance to current medicines. The effects of major histocompatibility complexes on transplanted organs are considered as well. Previously sold individually. A viewable/printable instructor’s guide is available online. A Cambridge Educational Production. (28 minutes)