b.

Te

Gastric Digestion

The stomach is an important muscular organ guarded at its entrance

and exit by sphincter muscles, It is not an empty cavity. It con-
tracts around the food and goes through an orderly sequence of con-
tractions and relaxations. These movements seem to further break up
food and add to it the gastric secretions. When the digestive process
has proceeded to a ¢ertain stage, the acid chyme causes pyloric
sphincter to open and let out a small quantity of contents into the
intestinese

Gastric Secretions
Character: Acid reaction (Hydrochloric acid)
Amount: Three pints daily
Secretions: (a) Psychic (bv) Secretogogues
Enzymes; (a) Pepsin (bd) Rennin

Intestinal Digestion

Movements of Intestines: Peristalsis is slower and gentler than in

 

the esophagus. Rhythmic motion moves food along in stages.

Secretions: Bile, pancreatic juice; intestinal juice.

The secretions of the intestines are alkaline in reaction. This ena-
bles them to neutralize acids coming from the stomach, those due to
bacterial fermentation of sugars, and those formed by fat digestion.

Bile: A secretion of liver and temporarily stored in gall bladder.
Action;
(a) Stimulate splitting of fats by pancreatic juice.
(ob) Enters into new formation of soans with fatty acids.
{c) Promotes peristalsis.
(a4) Helps to control bacteria.

Pancreatic juice: Amount, i pint daily. Action, on all three
forms of foodstuffs. Enzymes: Amylopsin; Trypsin; and
Steapsin (or amylase, protease, lipase).

 

Intestinal juice: Completes preparation of both proteins and car-
bohydrates for acsorption.

 

Enzymes: (a) Invertase)
Maltase ) bring about final changes in sugars.
lactase )

(b) Erepsin ) completes splitting of some pro-
tcins into amino acids.