BIOL 4160 Final - BIOL 4160 Final Chapter 16 Digestion...

BIOL 4160 Final
Chapter 16: Digestion
 Transfer nutrients, water and
electrolytes from ingested food into
body’s internal environment
 Four basic process: motility,
secretion, digestion, absorption
Digestion of organics
 Carbohydrates: most ingest are
polysaccharides [starch,
glycogen, cellulose (indigestible
fiber)]; disaccharides [sucrose
(glucose-frucose), lactose
(glucose-galactose)]; digestion
leads to absorbable
monosaccharides
 Proteins: proteins and peptide;
small peptides and amino acids are
the absorbable units
 Lipids/fats: most in form of
triglycerides (glycerol + 3 fatty
acid molecules); fat digestion
yields monoglycerides and free
fatty acids
Digestive tract wall has four tissue layers: (listed from the innermost out) mucosa, submucosa, muscularis
externa, serosa
 Wall has same general structure from esophagus to anus
Mucosa
 Lines the luminal
surface of the
digestive tract
 Divides into 3
layers:
o Mucous
membrane: inner epithelial layer that serves as a protective surface
o Lamina propria: thin middle layer of connective tissue; contains GALT- gut associated
lymphoid tissue – combats intestinal bacteria
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