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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