Digestive Physiology

INTRODUCTION

Digestion is a process to breakdown food from a complex molecules into a  simpler molecules, so it can be absorbed  by the body  into the bloodstream.

There are two types of digestion which is mechanical and chemical digestion. Mechanical digestion is a process to reduce the size of food particles and only happen in the mouth where food is chewed.

Chemical digestion is to further reduce the size of particles and prepare them for absorption through chemical reaction such as enzyme, it begin when the food mixed with saliva to break down starches in the mouth and churning of the stomach and mixing with enzymes. Addition of chemicals (acid, bile, enzymes, and water) to break down complex molecules into simple structures.

These are terms usually used in digestion:-

1. Ingestion

Is the act of taking food and drink into the body by the mouth (eating).

2. Absorption

Is the movement of nutrients from the digestive system to the circulatory and lymphatic capillaries through osmosis, active transport, and diffusion. In digestive system, absorption mostly takes place in small intestine.

3. Egestion

Is the Removal of undigested materials from the digestive tract through the process of defecation.

After chewing and swallowing, it takes 5 to 10 seconds for food to pass down the esophagus to the stomach, where it spends 2 to 6 hours being partially digested.

Final digestion and nutrient absorption occur in the small intestine over a period of 5 to 6 hours. •

In 12 to 24 hours, any undigested material passes through the large intestine, and feces are expelled through the anus.

 

There are for main organ and accessory organ in digestive system. The main organs are the mouth, pharynx, esophagus, stomach, small and large intestine. While accessory organ are the pancreas, gall bladder and liver.