Themes from other units with overlapping functions:
Types of epithelial cells
Key points from this chapter:
The four digestive processes are:
digestion, absorption, motility, and secretion.
The three phases of digestion are: cephalic phase, gastric phase, intestinal phase.
Digestion of carbohydrates, proteins, and fats takes place in multiple regions of the GI tract.
Digestion of each type of biomolecule requires specific enzymes and is sensitive to pH.
Absorption processes differ for each biomolecule, but absorption of most nutrients takes place
in the small intestine.
Motility involves peristaltic and circular (circumferential, segmental) contractions of the GI
tract smooth muscle. Motility is under nervous, hormonal, and local chemical control.
The GI tract secretes 7L of fluid a day.
These secretions include: fluids rich in ions, enzymes
Ion secretion and absorption in the digestive system are similar to ion transport in
There are two reflex patterns that are involved in the regulation of GI function:
and long reflexes.
Numerous digestive hormones also control GI function.
FUNCTION AND PROCESSES OF THE DIGESTIVE SYSTEM
ANATOMY OF THE DIGESTIVE SYSTEM
Epithelial cells, smooth muscle cells, mucosa, submucosa, submuscosal plexus, myenteric
The Digestive System Consists of the GI Tract and Accessory Glandular Organs
esophagus, stomach, small intestine, large intestine, colon, feces, rectum, anus
Accessory organs: pancreas, liver, gall bladder
The GI Tract Wall Has Four Layers
1) Mucosa (mucosa, lamina propria, muscularis mucosa, villi, microvilli, gastric glands, crypts,
2) Submucosa (submucosal plexus- enteric nervous system)
3) Muscularis Externa (myenteric plexus-enteric nervous system, peritoneal membrane, mesentery)
Gastrointestinal Smooth Muscle Contracts Spontaneously
Key words: tonic contractions, phasic contractions, slow-wave potentials, interstitial cells of Cajal
GI Smooth Muscle Exhibits Different Patterns of Contraction
Key words: migrating motor complex, peristaltic contractions, segmental contractions
GASTROINTESTINAL PHYSIOLOGY /