Some young animals grow inside a closed egg. Have you ever wondered how to breathe in the hard egg shell that does not have visible holes to allow basic oxygen to pass through vital functions?
Egg whites play a protective role as well as a source of protein, while saffar - or egg - keeps the egg warm and provides nutrients for the fetus to grow inside. But what about oxygen? Have you ever wondered how a chick or a small reptile, such as a crocodile or crocodile, can breathe while inside an egg?
The chick inside an egg will choke and die if the egg is placed in the water, confirming the fetus's ability inside the egg to absorb oxygen from the air outside the egg through narrow pores in the external egg shell and thin membrane beneath it.
This is achieved with the help of a membrane bag (chorion membrane, amnion membrane, and allantois membrane), connected to one end of the chick intestine, while the other end is located close to the inner surface of the egg shell.
The oxygen then spreads through the cortex and through the blood vessels in the sac. The carbon dioxide produced outside the egg is also expelled in the same way, which is essential for the health of the chicks. Keeping the waste inside the egg and allowing it to accumulate over time may not be what the chick likes.
When the chick hatchs, its choroid membrane leaves behind the egg shell from the inside, the Guardian newspaper reported.
This is one of the most remarkable things in embryology, as it reveals more commonalities with other animals than human thought previously. Similarly to the chorionic mammals, in the uterus, placenta and umbilical cord allow access to the food and oxygen needed by the embryos of the mother's blood, and disposal of waste in the same way.
Source:
https://www.scientificamerican.com/article/bring-science-home-chick-breathe-inside-shell/