Alveoli are the basic functional units of the human respiratory system, acting as tiny air sacs that exchange gases. Air inhaled through the mouth and nose flows into the lungs through the branched ...

An organ is a group of tissues that work together to perform a specific task in the body, such as digesting nutrients or producing chemical messengers that enable brain cells to communicate. Although ...

The human body is a wonderous thing, especially when you consider how intricate and efficient each bodily system is. For instance, an adult’s blood vessels could encircle the earth 2.5 times if ...