Human Physiology

Lesson 17 : Digestive System Overview


Digestive process includes ingestion solid food items, drinking of liquid food, its digestion (enzymatic & microbial), absorption and assimilation in the body. The food is present in nature in complex form which cannot be directly utilized by animal’s body/cells. The digestive system converts the complex food (starch, proteins, lipids etc) into simpler absorbable form (glucose, amino acids and fatty acids) with the help of various digestive enzymes. Human being requires food in order to provide energy for its body activities, growth, tissue repair and physical work. Therefore this system constitutes an important system of human body.

Interesting features are:

  • The average adult human being consumes about 550 kilograms of food each year.
  • In a healthy person, food usually spends up to one minute in the mouth, 10-20 seconds in the esophagus, 1-3 hours in the stomach, 2-4 hours in the small intestine and 6-18 hours in the large intestine.
  • The salivary glands produce about 1.5 liters of saliva each day, mainly at meal times. Saliva also neutralizes food acids, kill bacteria and helping prevent tooth decay.
Last modified: Tuesday, 10 April 2012, 7:08 AM