Cortisol and other hormones release a surge of energy in the form of glucose (sugar), which the body can use to fight or flee. That rush of glucose is no problem if your body's insulin response is working correctly.
Notice that the kittensâ ears are just beginning to unfold, though their eyes remain closed. Their sense of smell, hearing, and taste are slowly starting to develop. Tweed is only three days old. After almost a week, the kittens begin to wiggle around on their own a little bit and their eyes start to open.
Another article that might be helpful is Care of the Orphaned Kitten. A newborn kitten is born blind. Its eyes normally do not open until it is 10 to 12 days old. Kittens' ear canals, also, are not patent for a few days after birth, though these neonates still do have some ability to appreciate sounds.