Extracts from this document... Introduction. ﻿Explain how the digestive, cardiovascular and respiratory systems are interrelated There are many systems within the body; all the systems have to work with one another in order to keep the body going and functioning as it should.he food that is eaten is digested by the digestive system and the nutrients are given to the body via the blood, this is the same for the respiratory system as oxygen that is breathed in allows us to breathe as well as providing it to the rest of the body via the heart. ...read more.