Motility

Storage of waste

Defecation

Secretions

IngestionMouth

Pharynx Receiving

Foregut

Crop

ConductingStorageDigestion

Midgut (stomach)Digestion (acidic)

Hindgut

Digestion (basic)Absorption

Assimilation

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

Salivary centerin medulla

Autonomic nerves

Salivary glands

Other inputs

Salivary secretion

Pressure receptorsand chemoreceptors

in mouth

Conditioned reflex

+

+

Simplereflex

+

+

+

Fig. 14-6, p.622

Fig. 14-7, p.624

Fig. 14-8, p.627Duodenum

Smoothmuscle

FundusEsophagus

Gastroesophagealsphincter

Body

Stomachfolds

Oxynticmucosa

AntrumPyloricglandarea

Pyloricsphincter

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

Fig. 14-12, p.638

Stomach

Blood

Hormones(insulin,glucagon)

The glandular portions ofthe pancreas are grosslyexaggerated.

Endocrine portionof pancreas(islets of Langerhans)

Exocrine portion of pancreas(acinar and duct cells)

Acinar cellssecrete digestiveenzymes

Duct cellssecrete aqueousNaHCO3 solution

Duodenum

Bile ductfrom liver

Acid induodenal

lumen

Fat and proteinproducts in

duodenal lumen

Secretin releasefrom duodenal

mucosa

CCK releasefrom duodenal

mucosa

Secretion of aqueousNaHCO3 solution into

duodenal lumen

Secretion ofpancreatic digestive

enzymes intoduodenal lumen

Pancreatic ductcells

Pancreatic acinarcells

(secretin carriedby blood)

(CCK carriedby blood)

Neutralizes Digests

+ +

Fig. 14-13, p.640

Fig. 14-14, p.641

Fig. 14-15, p.642

Fig. 14-16, p.642

Large fat droplet

Lipid emulsion

Small lipid (fat) droplet with bile salt moleculesadsorbed on its surface

Lipid-soluble portion(derived from cholesterol)

Negatively charged H2O-soluble portion (a carboxyl group at the end of a glycineor taurine chain)

Through action of bile salts

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

Fig. 14-26, p.657

Transverse colon

Internal anal sphincter(smooth muscle)

Taeniae coli

Ileocecal valve

Ascending colon

RectumCecum

Appendix

Anal canal

External anal sphincter(skeletal muscle)

Sigmoid colon

Descending colon

Haustra

Fig. 14-27b, p.661

Reticulum

(b)

To smallintestine

Rumen

Abomasum

Omasum