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Ingestion
Mouth
Pharynx
Receiving
Foregut
Conducting
Storage
Digestion
Crop
Motility
Midgut (stomach)
Digestion (acidic)
Secretions
Digestion (basic)
Absorption
Assimilation
Hindgut
Storage of waste
Defecation
Fig. 14-1, p.613
Four basic digestive processes
• Motility: muscular contractions within gut tube that
mix and move forward the contents of the digestive
tract
• Secretion: secretion of mucus, water, electrolytes,
enzymes,
• Digestion: broken down structurally complex
foodstuffes into smaller, absorbable units
• Absorption: transfer absorbable units from digestive
tract lumen into the blood or hemolymph or body
cavity.
Fig. 14-2b, p.615
Fig. 14-2a, p.615
Table 14-1, p.616
Fig. 14-4, p.618
Cerebral cortex
+
Other inputs
+
Salivary center
in medulla
+
Conditioned
reflex
+
Pressure receptors
and chemoreceptors
in mouth
Simple
reflex
Autonomic nerves
+
Salivary glands
Salivary secretion
Fig. 14-6, p.622
Fig. 14-7, p.624
Esophagus
Fundus
Gastroesophageal
sphincter
Smooth
muscle
Body
Pyloric
sphincter
Stomach
folds
Oxyntic
mucosa
Duodenum
Pyloric
gland
area
Antrum
Fig. 14-8, p.627
Three main function of stomach
• Store ingested food
• Chemical digestion with HCl and enzymes
• Produce chyme (a thick, liquid mixture)
Fig. 14-9, p.629
Table 14-2, p.629
Table 14-3, p.632
Fig. 14-10, p.633
Fig. 14-11, p.634
Table 14-4, p.635
p.636
Table 14-5, p.636
Bile duct
from liver
Stomach
Duodenum
Hormones
(insulin,
glucagon)
Blood
Duct cells
secrete aqueous
NaHCO3 solution
Acinar cells
secrete digestive
enzymes
Exocrine portion of pancreas
(acinar and duct cells)
Endocrine portion
of pancreas
(islets of Langerhans)
The glandular portions of
the pancreas are grossly
exaggerated.
Fig. 14-12, p.638
Acid in
duodenal
lumen
Fat and protein
products in
duodenal lumen
Secretin release
from duodenal
mucosa
CCK release
from duodenal
mucosa
+
(secretin
carried
by blood)
Neutralizes
(CCK carried
by blood)
Digests
+
Pancreatic duct
cells
Pancreatic acinar
cells
Secretion of aqueous
NaHCO3 solution into
duodenal lumen
Secretion of
pancreatic digestive
enzymes into
duodenal lumen
Fig. 14-13, p.640
Fig. 14-14, p.641
Fig. 14-15, p.642
Fig. 14-16, p.642
Negatively charged H2Osoluble portion (a carboxyl
group at the end of a glycine
or taurine chain)
Lipid-soluble portion
(derived from cholesterol)
Small lipid (fat) droplet
with bile salt molecules
adsorbed on its surface
Large fat droplet
Through action of bile salts
Lipid emulsion
Fig. 14-17, p.644
Fig. 14-18, p.645
Fig. 14-19, p.646
Fig. 14-20, p.647
Table 14-6, p.649
Fig. 14-22, p.652
Fig. 14-23, p.653
Fig. 14-24, p.654
Table 14-7, p.655
Transverse colon
Haustra
Taeniae coli
Descending colon
Ascending colon
Ileocecal valve
Cecum
Appendix
Rectum
Internal anal sphincter
(smooth muscle)
Sigmoid colon
External anal sphincter
(skeletal muscle)
Anal canal
Fig. 14-26, p.657
Rumen
Reticulum
Omasum
Abomasum
To small
intestine
(b)
Fig. 14-27b, p.661