Satipatthana sutta describes a mindfulness of origination of the body, and mindfulness of dissolution of the body, and mindfulness of origination and dissolution of the body.
This can only and properly mean metabolism of the body, the way in which body and its cells are built from the matter that we take in every day by eating, and also its continuous breaking up, and discharge of used matter through excrement, urine, sweat, etc...
This practice of mindfulness implies a view in which food consists of atoms or elements, that are then combined in the body in a new way to form its diverse parts, like skin, bones, muscles, tendons, etc... Also that the body continually discharges, through defecating, matter that consists of elements, or of elements that consist of atoms.
This part in Satipatthana sutta describes mindfulness of the Metabolism of the Body, in the Body. This knowledge has been studied throroughly in modern Biology. You can hardly understand this particular form of mindfulness without knowledge of Biology. Through studying biology you naturally develop the mindfulness of origination processes and mindfulness of dissolution processes in the body.
According to Satipatthana Sutta this mindfulness can and will lead to full enlightenment in this life time. Knowledge of biology implies important Dharmic vision, important buddhist insight. That is clearly and accurately described in Biology, that is a liberating knowledge.