Our eyes are at work when reading text in books, writing calculations in your notebook, or even when throwing or kicking a ball. What does the inside of the eye look like? At the back of the eye, there is a tissue called the retina, which is lined with many types of cells that receive the light entering the eye and convert them into signals sent to the brain.
Humans breathe air in and out of their lungs roughly 20 times per minute or 30,000 times per day. What does the inside of the lungs look like? Inside the lungs are many tubular structures in which air passes through. These tubular structures are lined with various types of cells, with each cell type having different functions.