Digestive System Study Notes PDF

Digestive System Study Notes General Anatomy Alimentary Canal: Mouth to anus, technically "outside the body." GI Tract: Stomach and intestines. Accessory Organs: Liver, pancreas, gallbladder. Tissue Layers (Deepest to Superficial) 1. Mucosa: Epithelium, lamina propria,...

Digestive System Study Notes General Anatomy Alimentary Canal: Mouth to anus, technically "outside the body." GI Tract: Stomach and intestines. Accessory Organs: Liver, pancreas, gallbladder. Tissue Layers (Deepest to Superficial) 1. Mucosa: Epithelium, lamina propria, muscularis mucosae. 2. Submucosa: Loose connective tissue with vessels and nerves. 3. Muscularis Externa: Smooth muscle for mixing/propulsion. 4. Serosa: Areolar tissue + squamous mesothelium. Nervous System of the Alimentary Canal Enteric Nervous System (ENS): Nerves in esophagus, stomach, intestines. Submucosal Plexus: In submucosa. Myenteric Plexus: Between muscle layers of muscularis externa. Circulation Foregut: Esophageal arteries, celiac trunk. Midgut: Superior mesenteric artery. Hindgut: Inferior mesenteric artery. Hepatic Portal System: Veins from GI tract to liver. Peritoneum & Mesenteries Mesenteries: Connect organs to walls. Lesser Omentum: Stomach to liver. Greater Omentum: Apron-like; stomach’s greater curvature. Digestive Organs Overview Mouth & Teeth Cheeks/Lips: Labial frenulum, vestibule. Palate: Hard (bony) and soft (with uvula). Teeth: Incisors (cut), canines (tear), premolars/molars (grind). Salivary Glands  Parotid (near ear), Submandibular (under jaw), Sublingual (under tongue). Esophagus & Stomach Esophagus: Behind trachea, ends at lower esophageal sphincter. Stomach: Cardia, fundus, body, pylorus. Contains gastric rugae. Stomach Microscopic Anatomy Cells: Mucous (protection), Parietal (HCl), Chief (pepsinogen), Enteroendocrine (hormones). Small Intestine Sections: Duodenum (mixing), Jejunum (absorption), Ileum (lymphatic Peyer’s patches). Microscopic Anatomy: Villi with enterocytes (absorption), goblet cells (mucus). Large Intestine Sections: Cecum (appendix), colon (ascending, transverse, descending, sigmoid), rectum, anus. Features: Haustra (pouches), taeniae coli (muscle bands), goblet cells (mucus). Accessory Organs Liver Functions: Produces bile, processes blood. Anatomy: Right, left, quadrate, caudate lobes; falciform ligament. Microscopic: Hepatocytes, sinusoids, Kupffer cells. Gallbladder Stores/concentrates bile. Ducts: Cystic, hepatic, bile duct. Pancreas Exocrine (digestion): Acinar cells → enzymes, bicarbonate. Endocrine (hormones): Islets. Digestive System Diseases Appendicitis: Inflamed appendix, risk of rupture. Ascites: Fluid buildup in peritoneal cavity (often from liver disease). Ulcerative Colitis: Chronic large intestine inflammation. Crohn’s Disease: Inflammation of intestines with lesions and fibrosis. Urinary System Components: Organs: 2 kidneys, 2 ureters, bladder, urethra. Functions of Kidneys: Filter blood, excrete waste (mainly nitrogenous like urea). Kidney Anatomy: Position: Retroperitoneal, near vertebrae T12-L3 (right lower than left). Protection: Three layers: renal fascia, fat capsule, fibrous capsule. Structure: Hilum (entry/exit), cortex (outer), medulla (inner), renal pyramids, calyces, renal pelvis. Nephron (Functional Unit): Renal Corpuscle: Glomerulus + Bowman’s capsule, with podocytes forming filtration slits. Renal Tubules: PCT (reabsorption), nephron loop (water/salt balance), DCT (ion regulation), collecting ducts. Juxtaglomerular Apparatus: Regulates blood pressure using macula densa, granular cells (renin), mesangial cells. Other Structures: Ureters: Transport urine using smooth muscle peristalsis. Bladder: Stores urine, with detrusor muscle, rugae, and trigone. Urethra: Transports urine outside the body. In males, it has three sections; females have a shorter tube. Renal Failure: Types: Acute (reversible) or chronic (irreversible). Treatments: Hemodialysis, peritoneal dialysis, and transplants.