Human digestive system

Human digestive system

1. Digestion

   • Many Stages
     • Oral cavity
       • Digestion involves breakdown of food into smaller
         • Can be absorbed
         • and assimilated into the body
       • Saliva
         • The secretion of saliva
           • Helps to produce a bolus
             • can be swallowed to pass down the esophagus and into the stomach.
         • contains a catalytic enzyme
           • called amylase
             • starts to act on food in the mouth
   • helped
     • by the muscular contractions of peristalsis
       • Peristalsis is the rhythmic contraction of muscles
         • Begins In the esophagus
           • and continues along the wall of the stomach
           • and the rest of the gastrointestinal tract
         • This initially results in the production of chyme which when fully broken down in the small intestine is absorbed as chyle into the lymphatic system.
     • by the mastication of food by the teeth
   • Gastric juice in the stomach is essential
     • production of mucus in the stomach.

2. Most of the digestion of food takes place in the small intestine

3. Water and some minerals are reabsorbed back into the blood, in the colon of the large intestine.

4. The waste products of digestion are defecated from the anus via the rectum

5. There are several organs and other components involved in the digestion of food.

   • The organs know as the accesory digestive glands
     • Liver
     • Gall bladder
     • pancreas
     • other components
       • The mouth
       • Teeth
       • Epiglottis

6. The largest structure is the gastrointestinal tract (GI tract).

   • This starts at the mouth and ends at the anus
     • covering a distance of about nine (9) meters
   • The largest part of the GI tract is the colon or large intestine
     • Water is absorbed here and remaining waste matter is stored prior to defecation.

7. A major digestive organ is the stomach.

   • Within its mucosa are millions of embedded gastric glands.
     • Their secretions are vital to the functioning of the organ