Which part of the human body is most similar to stomata in plants?

Lungs are the part of the human’s body which have similar functions as stomata in plants.

Humans breathe through the lungs, bringing oxygen to the blood and getting rid of carbon dioxide. The blood transports the breathed-in oxygen through the body, where it is used by the cells, and takes carbon dioxide back to the lungs, where it is breathed out.

Plants, on the other hand, have very small structures (like holes) on the underneath of leaves, called stomata, which let the carbon dioxide and oxygen in and out. Stomata are not just simple holes, they contain guard cells that regulate opening and closing so that the plant does not lose too much water.