Friday, 10 June 2011

Digestion

Digestion

Food undergoes six major processes:



1. Ingestion : process of eating


2. Propulsion : passing of food down the GI tract swallowing : voluntary peristalsis : reflex, involuntary, involves alternating contractions of muscles in body walls of GI organs


3. Mechanical digestion


prepares food for chemical digestion includes chewing, mixing with saliva by tongue action, churning in stomach...


4. Chemical digestion


catabolic steps in which food is broken down to basic building blocks accomplished by enzymes in digestive juices


5. Absorption : passage of food particles into the blood-lymph


6. Defecation : elimination of indigestible food substances




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