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Renal Pelvis ----> Ureter -----> Bladder
Mucosa: Transitional epithelium - lamina propria
Muscularis: Smooth muscle Longitudinal inner layerCircular outer layer
Adventitia
URETER
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
KIDNEY DIALYSIS METHODS
Digestive System
Alimentary Canal and Associated Organs
Mouth TongueEsophagus TeethStomach Salivary GlandsSmall Intestine PancreasLarge Intestine Liver
Gall Bladder
Alimentary Canal
General Structure from Esophagus ---> Anus
Mucosa: Epithelium (varied composition)Lamina PropriaMuscularis 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
http://content.revolutionhealth.com/contentimages/images-image_popup-barrettsesophagus.jpg
-Damage to the lining of the esophagus due to leakage of stomach acid into the esophagus
Stratified Squamous Epithelium
Simple ColumnarEpithelium
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 defensemediated by IgA binding to
itsreceptor, pIgR, (the
secretorycomponent , 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.
www.bu.edu/histology/p/12001oba.htm
Immunological Defense
Peyer’s Patches
Lymph nodulescapped by specializedepithelial cells=>M Cells
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
MotilityMuscularis 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 glandPAS stain for
carbohydrates
millette.med.sc.edu/Lab%201%20pages/introduct...
Specialized Cells for Stomach SecretionParietal (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 HClPepsinogen--------->
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 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
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
www.aafp.org/afp/20071215/afp20071215p1795-u3.jpg
Normal Intestine
Celiac Disease
Large Intestine
Simple columnar epitheliumAbsorption of water and electrolytes
Columnar absorptive cellsCrypts of LieberkuhnGoblet 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 lumen2) distention of stomach wall3) 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
http://www.uwgi.org/gut/stomach_03.asp
Gastrin produced by G cell
HCl produced by parietal cell
Gastrin stimulates Parietal Cells
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