All systems in the human body work together to maintain homeostasis and normal functioning of the body. The five main systems are the digestive, circulatory, respiratory, transport, and excretory systems. These systems are then themselves made up of organs, tissues and cells. All systems are interdependent, so if one system fails it will impact the others. The function of the human body's digestive system is to break down macromolecules into their individual monomers so that the body can process them. There are two main types of digestion in the body. These are mechanical digestion and chemical digestion. Mechanical digestion is the mechanical process of breaking down food particles into smaller pieces. Chemical digestion is the secretion of enzymes and chemicals that further break down food into individual molecules. Some common enzymes in the human body are amylase, pepsin, and lipase. Enzymes are catalysts that speed up reactions but are not themselves reactants. Different enzymes also react on different substrates, for example, amylase reacts on carbohydrates....