Why are the lungs of the fetal pig actually non-functional?

Question

Pig dissection.

Answer 1

Because the fetal pig doesn't have access to air to breathe. The pig mother does the breathing for her fetus.

Answer 2

Fetal Pig Lungs

Answer 3

I agree with the previous two answers. The lungs develop last, since they aren't useful until after birth.

As for the mechanism, it is because the lungs haven't begun to produce surfactant yet. The surfactant is a natural detergent that breaks the surface tension of the water in the lungs. Since there is so much surface area in the lungs, and the alveoli are so tiny, the surface tension of the thin layer of water in the lungs (necessary for gas diffusion) will hold the tiny spaces closed. Without surfactant, it would be almost impossible to inflate the lungs due to the force of the surface tension.

When human babies are born very premature, this is often a problem. The surface tension can be so strong that it makes artificial respiration useless (the lungs simply cannot be inflated without damaging them). Instead, doctors can use an oxygenated fluid to fill the lungs and take the place of air (like the liquid breathing system in the movie "The Abyss"). This bypasses the surface tension problem, though method is still less than perfect, and can have negative side effects.

Answer 4

The lung are one of the last organs to fully form because in utero the fetus does not breathe and has no use for them.

One of the most common problems with premature human babies is maintaining breathing because their lungs are not fully formed