Buccinator Sublingual gland Wharton’s duct Stensen’s duct Masseter muscle Parotid gland Mandible Submaxillary Gland Buccal Cavity: Primary Salivary Glands

Filtration: In the Acinus is Primarily Passive Acinar cells Myoepithelial cell Ductal cells Acinus Myoepithelial cell Intercalated duct Striated duct Organization of the “Salivon”

Digestive:  -Amylase: Starch Digestion -pH optima 7.0; Active in Proximal Stomach -Ligual Lipase: Fat Digestion -pH optima ~4.0; does not require bile salts Lubrication/Protection: -Anti-Bacterial: I -, SCN -, Secretory IgA, Lysozyme and Lactoferrin -Anti-Corrosive: HCO 3 to buffer pH; F - Ca 2+. -Lubrication: Mucus- Mucopolysaccharides, H 2 O - Coat the Food to Aid in Swallowing-Taste Prevent Abrasion Functions of Saliva: Digestion, Protection-Lubrication

Filtration: In the Acinus is Primarily Passive Organization of the “Salivon” Acinar cells Myoepithelial cell Ductal cells Acinus Myoepithelial cell Intercalated duct Striated duct Capillaries SP Acetylcholine SP: Substance P

Stomach Anatomy

Gastric Lumen Gastric Pits Columnar Epithelium Lamina Propria Gastric Gland Lymph Node Lymphatics Mucosa Sub- Mucosa Mucularis Serosa Gastric Pits and Glands

Gastric Lumen Mucus Superficial epithelial cells Mucus neck cells Parietal cells Peptic cells (Oxyntic) GASTRIC GLANDS Gastric Pits

The Epithelial Protective Barrier Tight Junctions between Adjacent Cells Mucus and Bicarbonate Secretion Rapid Turnover – Cell Migration and Proliferation : All Appear to be Driven by Prostaglandins

Oxyntic Gland Secretions Peptic GastroferrinIron Binding Protein P Pepsin-ogen Protease D Mucus Neck Mucopolysaccharides; HCO 3 P Oxyntic Intrinsic Factor B12 BindingD Protein HCl Digestion/ P/D “denaturation” Cell Type Component Function: (P/D) P- Protective; D- Digestive

Protein Digestion : - Activates Pepsin - Denatures and Solubilizes Tissue Protective: Kills Bacteria Roles of HCl in the Stomach

ATP K+K+ K+K+ K+K+ H+H+ H+H+ Na + Cl - HCO 3 - H 2 CO 3 CO 2 HCO 3 - Na + Lumen of gland ATP Canaliculus Metabolism Cl - CA CA – Carbonic Anhydrase Baso- Lateral The Oxyntic Cell

CO 2 + H 2 O H 2 CO 3 HCO H + Role of Carbonic Anhydrase CA

Key Players: HCl Secretion H + / K + ATPase : Lumenal Omeprazole Carbonic Cytosolic Acetozolamide Anhydrase Na/K ATPase BasolateralOuabain K + / Cl - cotransport : Lumenal Cl - / HCO 3 antiport: Basolateral Location Inhibitor

Acetylcholine Gastrin Histamine Ca 2+ La 2+ H+H+ A A CM A ATP cAMP Adenylate Cyclase Blocks Does not block Ca 2+ IP 3 A - ATROPINE Ln 2+ - Lanthanum CM - Cimetidine H + Secretion

Phases of Secretion Cephalic Smell, Taste Central reflexes Gastric Chyme Enters Stomach Distension, Local Effects Amino Acids IntestinalChyme Enters Local Feedback the Intestine Inter-Digestive Histamine Basal Release PhaseStimuli Pathway

Primary Mechanisms for Inhibiting HCl Secretion Antrum Acidification pH < 3 Somatostatin Inhibition ( Gastric ) Maximal pH < 1of Gastrin Secretion Duodenum Distension Enteric (Local) Reflexes ( Intestinal )pH < 6 Fat and Peptides Entero-gastrone? Location (Phase) StimuliPathway

Ach GRP Vagus nerves Gastrin Cell Somato- statin Cell Digested Protein H+H+ + Regulation of G-Cell Secretion Myenteric Plexus

Antrum Body ECL