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Announcements No Class on November 23 rd 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.
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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
BLADDER http://www.visualsunlimited.com/browse/vu306/vu306638.html
Urethra Epithelium: Female: Transitional----> Stratified Squamous Male: Transitional----> Stratified or Pseudostratified Columnar Stratified Squamous
Digestive System Alimentary Canal and Associated Organs Mouth Tongue Esophagus Teeth Stomach Salivary Glands Small Intestine Pancreas Large Intestine 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
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). pIgR-driven export of dimeric IgA with J chain (IgA+J) Neutralization of infecting virus and transport of viral products from the lumen. Intracellular neutralization of endotoxin (LPS) from Gram-negative bacteria. 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 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
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
Specialized Cells of the Small Intestine Enterocytes (intestinal absorptive cells) Paneth cells- secrete antimicrobial substances Enteroendocrine cells- release 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