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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