Ingestion Mouth Pharynx Receiving Foregut Conducting Storage Digestion

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 -2 b, p. 615

Fig. 14 -2 a, 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 Na. HCO 3 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 Neutralizes by blood) + (CCK carried by blood) Digests + Pancreatic duct cells Pancreatic acinar cells Secretion of aqueous Na. HCO 3 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 H 2 Osoluble 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 -27 b, p. 661