Lungs. An animation showing structure of lungs and gas exchange. Note that all tissues: lungs, alveoli, blood capillaries, red blood cells, etc. are all constructed from cells that have grown and differentiated in special ways.
Intestines. A video showing cellular structure with animation of food being absorbed from intestine into blood. The film includes much technical terminology, which can be ignored while maintaining a focus how structure facilitates function.
Nervous system. Cellular structure and function animation