This animation shows the immune system reacting (or overreacting) at the cellular level. It describes what happens when an allergen, like dander or pollen, enters the body. It also shows how some allergy medicines work, like anti-histamines.

The animated video, narrated by a physician, describes the two main types of stroke: ischemic and hemorrhagic stroke. Ischemic strokes are further subdivided into thrombotic strokes and embolic strokes while hemorrhagic strokes are classified into subarachnoid hemorrhage and intracerebral hemorrhage. The location of the stroke in the brain directly influences the kind and degree of neurological deficit, which is discussed.

This narrated animation explains how normal cells sometimes change and turn into cancer cells. It touches on some of the causes and the prevalence of cancer and cancer deaths in the population.

The animation explains how the lungs provide oxygen to and remove carbon dioxide from the blood. The specialized anatomy of the air sac in the lung allows the gas exchange to occur efficiently, as discussed and shown in the video.