Preliminary
Comments: Homeostasis is a state of the body in which conditions inside the body are at a proper level and are being held rather steady with only slight fluctuations. This state is necessary for proper cell functioning and, therefore, for survival of the body. This tape shows the fundamental activities necessary for maintaining homeostasis.
In people, these activities include the following: (1) Using energy to remove the material of which they are made. (2) Using sheer size, and monitors, signals, and adjusting mechanisms to keep conditions relatively constant. (3) Using energy, changes in material, and adjusting systems to repair damage.
The tape also points out the roles of health professionals in maintaining homeostasis and, thereby, maintaining human life, by serving as back-up systems when the internal and normally automatic maintenance activities are not adequate.
Scenes: Twenty-story tall cooling tower which seems to form from a pile of rubble.
Narrator: Usually things fall apart and become disorganized. Usually things do not build themselves up.
Scenes: Old stone building with statues, fountains, and gardens.
Narrator: Though apparently unchanging, things actually are deteriorating, though sometimes slowly. Things which deteriorate slowly do so because the material which makes them up is always the same material. Nothing is deliberately or routinely removed or replaced. They are close systems.
Scene: Fountain
Narrator: The fountain also is staying about the same shape but is different from the statues because its material, water, is constantly being removed and replaced simultaneously. Its shape fluctuates slightly but remains about the same. To have this happen, energy is needed. It comes from gravity.
Living things, like the fountain, have their material changing, using energy. Their energy comes from the sun for plants and from food for animals.
The fountain and living things are alike in that they are opensystems, using energy to remove and replace their matter and, thus, maintain themselves.
Scene: Steam engine operating
Narrator: The steam engine and animals like humans are similar in that both burn fuel (food) to get energy to do work. They are different in that the engine cannot get its own fuel or repair itself. Humans can and do.
Scene: Single-celled animals
Narrator: Cells are the smallest things which get food and "burn" it to work and maintain themselves. However, cells are very sensitive and must have a proper environment to survive. They use energy from food to keep their insides intact and different from their surroundings.
Scene: Hydra
Narrator: When many cells join together, they can specialize to get food more efficiently. They still may be very susceptible to the external environment.
Scene: Fish and dolphin
Narrator: When larger groups of cells form, they not only get food better but also help insulate each other from the harmful external environment. This promotes survival.
Scene: Supersonic jet
Narrator: The people in the jet are like cells inside a large animal. They are insulated from the harmful external environment. Moreover, they can adjust the internal environment to suit themselves, regardless of what is happening outside.
Scene: Small stunt plane
Narrator: The people in the small plane are like cells in a small animal. They are very exposed to the harmful external environment and their survival is threatened.
Scene: Inside large jet
Narrator: In the large jet, size is not the only thing keeping conditions stable. Control mechanisms detect and reverse any unfavorable change. This also helps the passengers (cells) survive. The more and better the adjustments possible, the better the chances of survival.
Scene: Claude Bernard
Narrator: Claude Bernard recognized that the more stable the internal environment of living things and the better the recognition and reversal of changes in that internal environment, the better the chances of survival. Modern medicine is essentially a process of substituting external recognition and control mechanisms from outside the body for those in the body which fail. (NOTE: This program fails to mention the great importance of preventive medicine!)
Scenes: Windmill with governor, steam engine, jet
Narrator: Like windmills and steam engines with their speed regulators and jets with their automatic pilots, living things use a lot of energy to do work and use a little of their energy to monitor their own conditions and send messages to reverse any undesirable changes. These are negative feedback systems which maintain stability. They involve monitors, signals, and actions to reverse changes and so, keep a dynamic equilibrium.
Scene: Laboratory
Narrator: The equilibrium maintained by living things is an active one because energy is used to keep things constant. Maintaining posture is an example.
Not only do living things have dynamic equilibrium like some machines, but they can repair themselves. Machines cannot. Repair begins with inflammation, which causes more blood to flow to the damaged area. The extra blood delivers extra material and white blood cells. The need is signaled by histamine released from injured cells (mast cells). [Note the margination, adhesion, and emigration of WBC's.]
Scene: Bath
Narrator: The body can also adjust to harmful external factors like temperature by holding more heat or releasing more heat, preventing the external temperature from affecting the internal temperature. Non-living things like a hot tea pot cannot maintain their temperature.
Scenes: Hospital with old man and premature baby
Narrator: Medical practitioners help people survive by learning about and designing substitutes for body monitors, signals, and adjusting mechanisms which fail or are not present. They provide substitute negative feedback systems like respirators, massages, pacemakers, and incubators. Note that the baby's small size makes it even more subject to environmental changes.
Scene: Space craft
Narrator: The space craft and medical practitioners provide substitute non-harmful environments and substitute negative feedback systems for the space men.
Scene: Laboratory
Narrator: The body creates a steady favorable environment for its cells since there is no such external environment. Energy is expended to do this.