This edition: Animal Structure
All animals are collections of billions of different types of cells and tissues, each specially adapted to its specific function. But each animal has a commonality: It achieves motion promoted by a musculoskeletal system and maintains equilibrium through homeostasis and feedback.
The program touches on the similarities and differences of integument, from reptile to amphibian and, ultimately, to mammals. In the first segment, against the backdrop of a “tortoise refuge,” Dr. David Reznick explains the relationships between tissues, organs, and organ systems. An animation illustrates different tissues in a tiny bit of skin, an organ that serves similar functions of protection and temperature regulation in many animals.
In the second segment, muscle atrophy in astronauts is used as a vehicle to describe the muscle system. Physiologist Kenneth Baldwin describes what causes muscle contractions on a cellular level.
In the final segment, thoroughbred-horse training leads to a discussion of the skeletal system. Dr. Reznick explains the dynamic nature of skeletal structure and bone cell structure.