Answer:Food, to be of use to the body, must enter the blood stream. This is achieve through the chemical and mechanical conversion of large food particles into smaller and simpler substances via a process known as digestion.
Explanation
Digestion start in the mouth and end at the anus. Its a complex process that involves basically 5 steps, namely: ingestion, digestion, absorption, excretion and Elimination.
These entire processes is achieve by the working together of several organs. And most important to note is that the secretions in the digestive tract are actually the secretion of various organs along the digestive tract.
The mouth:
This organ secret saliva. The content of saliva is basically 98% water, mucus, electrolyte and various enzyme, ( chief among them is ptyalin). Ptyalin convert starch to maltose.
The stomach:
This organ secret gastric juice and Hydrochloric acid. The juice contain 3 enzyme : Pepsin, Rennin, and gastric lipase.
Pepsin: they act on protein and change it into soluble peptones and dissolve protein covering of fat globules and set them free.
Rennin: act on milk and change them into curd
Gastric lipase: digest emulsified fat.
Hydrochloric acid: help to stop the action of saliva and kill germs.
The small intestine: Absorbs breaken down products of carbohydrates, proteins, lipids, nucleic acids, vitamins, minerals, water and also provide optimal medium for enzymatic reaction.
The secretion in this region is Bile and pancreatic juice. Bile help to emulsify fat and help to activate trpsin
Pancreatic juice are enzymatic in nature and contain : Amylase, Trypsin and lipase, sucrase,lactase,maltase. These help to convert food substances to their final state and they aid assimilation
