What are the three phases of digestive activities in the
gastrointestinal tract
The cephalic phase The gastric phase The
intestinal phase
What happens during the cephalic phase of digestion
The smell, sight, thought or initial taste of food activates
neural centers in the cerebral cortex, hypothalamus and brain stem
to prepare for digestion. Food is swallowed
What occurs during the gastric phase of digestion
Neural and hormonal mechanisms promote secretion of gastric juice and
increase gastric motility
What occurs during the intestinal phase of digestion
Begins when food enters the small intestine Neural and
hormonal responses promote the continued digestion of foods that
have reached the small intestine. In contrast to the
cephalic phase, this phase slows the process keeping everything in
order.
Development of digestive system
4th week - the endoderm forms a cavity called the primitive gut
Soon after, the mesoderm associates with the primitive gut
helping to form the digestive system
7th week - Continues to develop into the GI tract
Changes that occur as age advances
decreased secretory ability, motility, muscle tone
increased diseases /illnesses: periodontal, cancers, ulcers