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Announcements No Class on November 23rd Want some Independent Study Credits? SEE ME! Renal Pelvis ----> Ureter -----> Bladder Mucosa: Transitional epithelium - lamina propria Muscularis: Smooth muscle Longitudinal inner layer Circular outer layer Adventitia 25. URETER URETER BLADDER http://www.visualsunlimited.com/browse/vu306/vu306638.html Urethra Epithelium: Female: Transitional----> Stratified Squamous Male: Transitional----> Stratified or Pseudostratified Columnar Stratified Squamous KIDNEY DIALYSIS METHODS Digestive System Alimentary Canal and Associated Organs Mouth Esophagus Stomach Small Intestine Large Intestine Tongue Teeth Salivary Glands Pancreas Liver Gall Bladder Alimentary Canal General Structure from Esophagus ---> Anus Mucosa: Epithelium (varied composition) Lamina Propria Muscularis Mucosa (smooth muscle) Submucosa: Dense irregular connective tissue Muscularis externa: Two layers of smooth muscle Serosa: simple squamous epithelium, connective tissue Function of the Alimentary Canal Barrier: between internal and external environments Immunological Defense: site of lymphatic tissue Motility: movement of food Secretion: enzymes, mucous, acid, antibodies Absorption: products of digestion Barrier- Epithelium Oral Cavity: parakeratinized epithelium- most superficial cells do not lose nuclei tongue, gums, hard palate Connective tissue papilla Barrier- Epithelium Esophagus: stratified squamous epithelium Small and Large Intestine- tight junctions between columnar cells of simple epithelium Barrett’s Esophagus -Damage to the lining of the esophagus due to leakage of stomach acid into the esophagus Stratified Squamous Epithelium Simple Columnar Epithelium http://content.revolutionhealth.com/contentimages/images-image_popup-barrettsesophagus.jpg Esophagus: Normal stratified squamous epithelium Barrett’s Esophagus Barrett’s Esophagus Simple columnar epithelium, presence of goblet cells What if the barrier is breached? Immunological Defense Tonsils: ring of lymphatic tissue (lymphatic nodules or follicles) at entrance to respiratory and digestive tracts micro.magnet.fsu.edu/optics/intelplay/gallery... Adenoids: lymphatic tissue located high on the posterior wall of the pharynx. - similar to tonsils - clear antigens from air - reduced in adults - can be enlarged / inflamed SYMPTOMS: -mouth breathing -snoring -bad breath -chronic runny nose -sleep apnea -pulmonary hypertension -right-sided heart failure Immunological Defense Gut-associated lymphatic tissue (GALT): diffuse lymphatic tissue and lymphatic nodules in lamina propria of small and large intestine Striking in Ileum and Appendix => Peyer’s Patches MALT=Mucous associated lymphatic Tissue Immunological Defense: Lymphatic Tissue Plasma Cells secrete a special form of antibody, ==> secreted IgA -Dimeric -Linked via J chain and secretory component -More stable -More resistant to enzymatic digestion -in saliva, milk, and mucous membranes of respiratory and digestive tracts Possible modes of defense mediated by IgA binding to its receptor, pIgR, (the secretory component , SC). (a) pIgR-driven export of dimeric IgA with J chain (IgA+J) (b) Neutralization of infecting virus and transport of viral products from the lumen. (c) Intracellular neutralization of endotoxin (LPS) from Gram-negative bacteria. (d) Clearance of antigen (Ag) that has breached the mucosal barrier. From Trends Immunol. 2004, 25:150-57. Immunological Defense Peyer’s Patches Lymph nodules capped by specialized epithelial cells =>M Cells www.bu.edu/histology/p/12001oba.htm M Cells - Follicle-Associated Epithelium (FAE): epithelial cells associated with lymph nodules of MALT - look for absence of goblet cells over Peyer’s Patch - apical surface microfolds rather than microvilli - connected to neighbors with tight junctions M Cells - have extensive inpocketings of basal membrane containing T and B lymphocytes www.rcai.riken.go.jp/eng/group/epi/ M Cells: specialized for transepithelial transport: deliver intact foreign antigens and microorganisms from lumen to immune cells Motility Muscularis Mucosa: thin layer of smooth muscle responsible for moving the mucosa Motility Muscularis Externa: mixes, propels contents of lumen 2 thick layers of smooth muscle inner layer=> circularly-oriented layer -tight spiral outer layer=>longitudinally-oriented layer -loose spiral Between muscle layers- Nervous innervation Myenteric plexis (Auerbach’s plexis) Motility: Muscularis Externa Motility: Muscularis Externa Motility MUSCULARIS EXTERNA EXCEPTIONS: SKELETAL MUSCLE in proximal esophagus (upper 1/3) & anus MUSCULARIS EXTERNA EXCEPTIONS: Teniae Coli: 3 thickened bands of longitudinal layer of smooth muscle in the large intestine- Lumen Secretion - carried out by epithelial cells and associated glands - secretions include: Antibodies: IgA Lubrication substances- Mucous, Goblet cells! Aid for digestion: hydrochloric acid & enzymes Hormones Water -secretions from salivary glands, stomach, small and large intestine Before we discuss secretions: A PAUSE FOR A BIT OF GROSS ANATOMY! Anatomy of the Stomach 3 regions: Cardiac Pyloric Fundic Rugae: longitudinal folds or ridges on inner surface Anatomy of the Stomach 3 regions: Cardiac Pyloric Fundic Rugae: longitudinal folds or ridges on inner surface Simple columnar epithelium Each stomach region has distinctive glands. •Cardiac glands •Pyloric glands •Fundic glands -gastric pits -isthmus cell replication -neck -base or fundus Anatomy of the Small Intestine 3 components: Duodenum, Jeunum, Ileum - Plicae circularis - Villi - Microvilli - Simple columnar epithelium Anatomy of the Small Intestine Lubrication: Mucous Secretions Esophagus- Lubrication and protection from regurgitation of acidic stomach contents Stomach- surface mucous cells; mucous protects from abrasion, contains bicarbonate; protects mucosa from acidic stomach contents (chyme) Small Intestine- goblet cells, # increases from duodenum=> ileum Large Intestine- goblet cells, # increases toward rectum Specialized Cells for Stomach Secretion Surface Mucous Cells: gastic pit and neck of gastric gland PAS stain for carbohydrates millette.med.sc.edu/Lab%201%20pages/introduct... Specialized Cells for Stomach Secretion Parietal (Oxyntic) Cells: - neck & deep parts of fundic glands - release HCl and intrinsic factor (B12 absorption) - large** - triangular** - acidophilic** Parietal (Oxyntic) Cells Anti-parietal cell antibody Parietal (Oxyntic) Cells HCl Synthesis: H+ and Cl- ions pumped into intracellular canalicular system, HCl formed http://www.mfi.ku.dk/ppaulev/chapter22/images/22-10.jpg Specialized Cells for Stomach Secretion Chief Cells: deep in fundic glands, protein-secreting, lots of RER, basophilic, zymogen granules Secrete pepsinogen HCl Pepsinogen---------> Pepsin Specialized Cells for STOMACH Secretion Enteroendocrine cells: small - more common in gland base - pale, vesicles don’t fix well - may not reach lumen, but sample lumenal contents with microvilli -release variety of hormones into blood Enteroendocrine cells Specialized Cells of the Small Intestine Enterocytes (intestinal absorptive cells) Paneth cells- secrete antimicrobial substances Enteroendocrine cellsrelease hormones M cells- dome cells cap lymphatic nodules Goblet cells- mucous secreting Enterocytes (intestinal absorptive cells) Tall columnar cells Microvilli=>striated border Epithelial specializations -Terminal web - Tight junctions Secrete Digestive Enzymes Paneth Cells - base of intestinal glands large intense acidophilic granules phagocytose bacteria secrete lysozyme- digests bacterial cell wall Epithelial Renewal in Stomach and Small Intestine Celiac Disease (Sprue) - an inherited, autoimmune disease - lining of the small intestine damaged by eating gluten and other proteins found in wheat, barley, rye, and possibly oats. - exact cause unknown - flattening of intestinal villi http://www.nlm.nih.gov/medlineplus/ency/article/000233.htm Normal Intestine Celiac Disease www.aafp.org/afp/20071215/afp20071215p1795-u3.jpg Large Intestine Simple columnar epithelium Absorption of water and electrolytes Columnar absorptive cells Crypts of Lieberkuhn Goblet cells www.kumc.edu/.../histoweb/gitract/gi21.htm Ulcerative Colitis -An inflammatory bowel disease that affects the lining of the large intestine (colon) and rectum. Symptoms include: - Abdominal pain and cramping and sounds - Blood and pus in the stools - Diarrhea Treatments: - Diet and nutrition - Manage stress - Medications - Surgery Histology: Presence of crypt abscesses in which the crypt epithelium breaks down and the lumen fills with cells. The lamina propria is infiltrated with leukocytes. Secretion / Digestion / Absorption - Requires coordination of secretion and motility with ingestion NERVOUS AND HORMONAL SIGNALS Secretion / Digestion / Absorption - Requires coordination of secretion with ingestion - Must coordinate the: Release of saliva Release of digestive enzymes Release of HCl Release of bile from gall bladder Motility of gastrointestinal tract Secretion / Digestion / Absorption What signals might trigger release of hormones and digestive enzymes? Gastrin secretion: release from stomach enteroendocrine cells (G cells) is stimulated by 1) peptides and amino acids in stomach lumen 2) distention of stomach wall 3) sensory inputs --> neural innervation (GRP) - Parietal cells have gastrin receptors GASTRIN RELEASE HCl RELEASE PEPSIN ACTIVATION PROTEIN DIGESTION Enterochromaffin-like cell=ECL Cell Regulation Parietal Cell HCl secretion HCl produced by parietal cell Gastrin produced by G cell Gastrin stimulates Parietal Cells http://www.uwgi.org/gut/stomach_03.asp Choleocystokinin (CCK): hormone released from enteroendocrine cells of small intestine is stimulated by presence of H+, amino acids, and fatty acids - Pancreatic cells have CCK receptors**(may act through neurons innervating the pancreas in humans) CCK RELEASE (INTESTINAL ENDOENDOCRINE CELLS) PANCREATIC DIGESTIVE ENZYME RELEASE DIGESTION OF CARBOHYDRATES, PROTEINS, LIPIDS IN SMALL INTESTINE