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Home , Circular folds, Descending colon, Gastric pits, Hard palate, Haustrum (anatomy), Palate

(oral cavity) Salivary Submandibular glands gland

Esophagus

Stomach Pancreas () Gallbladder

Duodenum Small intestine Large intestine Anus © 2018 Pearson Education, Inc. 1

Nasopharynx Hard Oral cavity Uvula

Lips (labia) Palatine

Vestibule Lingual tonsil

Oropharynx Lingual frenulum

Epiglottis Tongue Laryngopharynx Hyoid

Esophagus Trachea (a) © 2018 Pearson Education, Inc. 2 Upper Gingivae ()

Soft palate

Uvula

Palatine tonsil

Oropharynx Tongue (b)

© 2018 Pearson Education, Inc. 3

Nasopharynx Hard palate Soft palate Oral cavity Uvula

Lips (labia)

Vestibule Lingual tonsil

Oropharynx Lingual frenulum

Epiglottis Tongue Laryngopharynx Hyoid bone

Esophagus Trachea (a) © 2018 Pearson Education, Inc. 4 Visceral Intrinsic plexuses • Myenteric nerve plexus • Submucosal nerve plexus

Submucosal glands

Mucosa • Surface • • Muscle layer

Submucosa Muscularis externa • Longitudinal muscle layer • Circular muscle layer Serosa (visceral peritoneum) Nerve Gland in Lumen mucosa Duct of gland Lymphoid tissue outside alimentary canal

© 2018 Pearson Education, Inc. 5

Diaphragm

Falciform ligament Lesser Liver omentum Spleen Pancreas Gallbladder Visceral peritoneum Transverse colon Greater omentum Parietal peritoneum

Small intestine Peritoneal cavity Uterus

Large intestine Cecum Rectum Anus Urinary bladder

(a) (b)

© 2018 Pearson Education, Inc. 6 Cardia Fundus

Esophagus

Muscularis Serosa externa • Longitudinal layer • Circular layer • Oblique layer Body

Lesser Rugae curvature of mucosa

Greater curvature

Duodenum Pyloric Pyloric sphincter antrum (a) (valve) © 2018 Pearson Education, Inc. 7

Fundus

Body

Rugae of mucosa

Pyloric Pyloric (b) sphincter antrum © 2018 Pearson Education, Inc. 8

Surface epithelium

Pyloric

sphincter pit Gastric Mucous neck cells

Parietal cells

Gastric

Gastric gland

Chief cells

(c) © 2018 Pearson Education, Inc. 9

Pepsinogen HCl

Parietal cells

Chief cells

Enteroendocrine (d) cell

© 2018 Pearson Education, Inc. 10 Right and left hepatic ducts from liver

Cystic duct Common hepatic duct and sphincter Accessory

Pancreas Gallbladder Jejunum Duodenal papilla Main pancreatic duct and sphincter Hepatopancreatic ampulla and sphincter Duodenum © 2018 Pearson Education, Inc. 11

Blood vessels serving the

Lumen Muscle layers (plicae circulares) Villi

(a) Small intestine

© 2018 Pearson Education, Inc. 12 Absorptive cells

Lacteal

Villus Blood capillaries

Lymphoid tissue Intestinal crypt Muscularis Venule mucosae

(b) Villi © 2018 Pearson Education, Inc. 13

Microvilli (brush border)

(c) Absorptive cells

© 2018 Pearson Education, Inc. 14 Left colic (splenic) flexure Transverse Right colic mesocolon (hepatic) flexure

Transverse colon

Haustrum Descending colon

Ascending colon

IIeum (cut) Cut edge of mesentery IIeocecal valve Teniae coli

Sigmoid colon Cecum

Appendix Rectum

Anal canal

© 2018 Pearson Education, Inc. 15

Enamel Dentin Crown Pulp cavity (contains blood vessels and ) Neck Gum (gingiva) Cement

Root canal Root Periodontal membrane (ligament)

Bone © 2018 Pearson Education, Inc. 16 Foodstuff Enzyme(s) and source Site of action

Starch and disaccharides

Digestion of Salivary amylase Mouth carbohydrates Pancreatic amylase Small intestine Oligosaccharides* and disaccharides

Brush border enzymes Small intestine Lactose Maltose Sucrose in small intestine (dextrinase, glucoamylase, lactase, maltase, Galactose Glucose Fructose and sucrase)

The monosaccharides glucose, galactose, and fructose Absorption of enter the capillary blood in the villi and are transported to carbohydrates the liver via the hepatic portal vein.

*Oligosaccharides consist of a few linked monosaccharides.

© 2018 Pearson Education, Inc. 17

Foodstuff Enzyme(s) and source Site of action

Protein of proteins Pepsin (stomach glands) Stomach in the presence of HCl Large polypeptides

Pancreatic enzymes Small intestine (trypsin, chymotrypsin, Small polypeptides carboxypeptidase)

Brush border enzymes Small intestine (aminopeptidase, Amino acids carboxypeptidase, (some dipeptides and dipeptidase) and tripeptides)

Absorption Amino acids enter the capillary blood in the villi and are of proteins transported to the liver via the hepatic portal vein.

© 2018 Pearson Education, Inc. 18 Foodstuff Enzyme(s) and source Site of action

Unemulsified fats Digestion Small intestine of fats Emulsified by the detergent action of bile salts from the liver

Pancreatic lipase Small intestine

Monoglycerides Glycerol and and fatty acids fatty acids

Fatty acids and monoglycerides enter the lacteals of the villi Absorption and are transported to the systemic circulation via the lymph of fats in the thoracic duct. (Glycerol and short-chain fatty acids are absorbed into the capillary blood in the villi and transported to the liver via the hepatic portal vein.)

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Ingestion Food Mechanical breakdown Pharynx • (mouth) Esophagus • Churning (stomach) Propulsion • Segmentation • (small intestine) (oropharynx) • Digestion (esophagus, stomach, small intestine, ) Stomach

Absorption Lymph vessel

Small intestine Blood Large vessel intestine Mainly H2O Feces

Anus

© 2018 Pearson Education, Inc. 20 Bolus of food

Tongue

Pharynx Epiglottis up Upper esophageal Glottis (lumen) sphincter of larynx

Trachea Esophagus

1 Upper esophageal sphincter contracted

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Uvula Bolus Epiglottis down

Larynx up Esophagus

2 Upper esophageal sphincter relaxed

© 2018 Pearson Education, Inc. 22 Bolus

3 Upper esophageal sphincter contracted

© 2018 Pearson Education, Inc. 23

Relaxed muscles

Cardioesophageal sphincter open

4 Cardioesophageal sphincter relaxed

© 2018 Pearson Education, Inc. 24 Pyloric Pyloric Pyloric valve valve valve closed slightly closed opened

1 Propulsion: Peristaltic 2 Grinding: The most 3 Retropulsion: The waves move from the fundus vigorous peristalsis and peristaltic wave closes the toward the pylorus. mixing action occur close pyloric valve, forcing most of to the pylorus. The pyloric the contents of the pylorus end of the stomach acts as backward into the stomach. a pump that delivers small amounts of into the duodenum.

© 2018 Pearson Education, Inc. 25

4 Secretin causes the liver to secrete more bile; CCK stimulates the gallbladder 1 Chyme entering to release stored duodenum causes bile and the duodenal entero- hepatopancreatic endocrine cells to sphincter to relax release cholecystokinin (allows bile from (CCK) and secretin. both sources to enter the duodenum). 2 CCK (red dots) and secretin (blue dots) 5 Stimulation enter the bloodstream. by vagal nerve fibers causes 3 Upon reaching the release of pancreas, CCK induces pancreatic juice secretion of enzyme- and weak rich pancreatic juice; contractions of secretin causes the gallbladder. secretion of bicarbonate- rich pancreatic juice.

© 2018 Pearson Education, Inc. 26 (a)

(b) © 2018 Pearson Education, Inc. 27

Tryptophan Beans and other Methionine legumes Valine Threonine Phenylalanine Leucine Corn and Isoleucine other grains Lysine

© 2018 Pearson Education, Inc. 28 (a) Carbohydrates: polysaccharides, disaccharides; composed of simple sugars (monosaccharides) ATP Glycogen and fat Polysaccharides Cellular uses broken down for ATP formation GI digestion to simple sugars To Excess stored as capillary glycogen or fat Broken down to glucose Monosaccharides and released to blood

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(b) Fats: composed of 1 glycerol molecule and 3 fatty acids; triglycerides Cellular ATP Fats are the Metabolized uses Lipid (fat) primary fuels by liver to Fatty in many cells acetic acid, etc. acids GI digestion to fatty acids and glycerol Insulation and fat Fats build myelin cushions to protect sheaths and cell body organs membranes Glycerol

© 2018 Pearson Education, Inc. 30 (c) Proteins: polymers of amino acids ATP formation if inadequate ATP glucose and fats or if essential Protein Normally amino acids are lacking infrequent Functional proteins GI digestion to (enzymes, , amino acids Cellular hemoglobin, etc.) uses Structural proteins Amino (connective tissue fibers, acids muscle proteins, etc.)

© 2018 Pearson Education, Inc. 31

(d) ATP formation (fueling the metabolic furnace): all categories of food can be oxidized to provide energy molecules (ATP) Carbon dioxide Cellular Monosaccharides metabolic “furnace”: Water Citric acid cycle Fatty acids and electron transport Amino acids chain (amine first removed ATP and combined with

CO2 by the liver to form urea)

© 2018 Pearson Education, Inc. 32 Glycogenesis: Glucose converted to glycogen and stored

IMBALANCE Stimulus: Rising blood glucose level HOMEOSTATIC BLOOD SUGAR

IMBALANCE Stimulus: Falling blood glucose level Glycogenolysis: Stored glycogen converted to glucose

Gluconeogenesis: Amino acids and fats converted to glucose © 2018 Pearson Education, Inc. 33