Fetus is thin and without much fat . HEAD Fetal brain waves begin to activate auditory and visual systems, both mouth and lips show more sensitivity. Eyes respond to light, while ears respond to sounds originating outside uterus. Permanent teeth buds appear high in gums. Nostrils begin to open.
Reflex movements improve.
These bloods vessels will eventually exchange oxygen and circulate it to tissues. Air sacs, alveoli, have developed in lungs and begin to produce surfactant, a substance that keeps the lung tissue from sticking to itself.