Lab 16 Glands Digestive Glands Introduction 16 –Digestive Glands A560 –Fall 2015 I. Introduction...

DigestiveGlandsLab16–DigestiveGlandsA560– Fall2015

I. IntroductionII. LearningObjectivesIII. SlidesandMicrographs

A. SalivaryGlands1. Parotidgland2. Submandibulargland

B. PancreasC. LiverD. GallBladder

IV. Summary

Fig15‐1,Junqueira,13th ed.

Lab16–DigestiveGlandsA560– Fall2015




IV. Summary

Learning Objectives

1. Review the secretory units of the salivary glands.

2. Understand the structure and function of the cuboidal epithelium cellscomprising the ducts.

3. Compare and contrast the histology and exocrine function of the pancreas withthat of the parotid salivary gland.

4. Understand the overall organization of lobes and vasculature in the liver.

5. Understand the microvascular features specific to the liver and the function ofthe hepatocytes.

6. Understand the origin of bile and the system transporting it from the liver.

7. Understand the structure of the gall bladder wall and how it facilitates theorgan’s function.





IV. Summary

ComparisonofMajorSalivaryGlands

Slide132:ParotidGland,H&E Slide11:SubmandibularGland,PAS&AB

• Compoundacinar• Serousacinionly

• Compoundtubuloacinar• Serousaciniandmucuous tubules• Serousdemilunes





IV. Summary

ExcretoryPathwayfromSalivaryGlands

Secretory cells

Intercalated ducts: small/closed‐appearing lumen (generally smaller than acinus); linedwith simple squamous or cuboidal epithelium; often surrounded by myoepithelial cells

Striated (intralobular) ducts: larger, open lumen; lined with simple cuboidal (or columnar)cells with basal striations

Interlobular ducts: in septa; increasing size; and epithelium transitioning from simplecuboidal to columnar epithelium; may be stratified

Excretory (lobar) ducts: largest; from superficial and deep lobes of gland; stratifiedcuboidal or maybe columnar epithelium

“Excretory”

Intralob

ular





IV. Summary

Slide132:ParotidGland,H&E

septa dividelobulesofglands

capsule

lobule

excretoryduct

striatedductspresence of ducts distinguishes organ as exocrine gland – sonot to be confused with any of the lymphoid structures





IV. Summary


adipose excretoryductstriatedducts

septum





IV. Summary


excretoryductinseptum

striatedductparenchymaiscomposedofserousacinionly

adipose





IV. Summary


striatedductwithfaint“striation”’inbasalhalfof

cellperpendiculartolumen





IV. Summary

Slide11:SubmandibularGland,PASAB

Darkstainingcells=mucouscellsLightstainingcells=serouscells

parenchymaconsistsofboth serous and

mucouscells

striatedduct





IV. Summary

Slide11:SubmandibularGland,PASAB

excretoryduct

Noticethedifferenceintissuelininglumenbetweenductandvessel





IV. Summary

Serous acini secrete non‐glycosylated protein products and stain strongly due to theirabundant rER and secretory granules; Mucous acini secrete mucus (mucopolysaccharide)and contain little rER so tend to be poorer‐staining with most general stains

Slide72:SubmandibularGland,H&Phloxine

Mucouscells

Mucous=Adj.Mucus=Noun

Serouscells

Serousdemilune:“halfmoon”shapeofserousportionofglandsurroundingmucousportion

striatedducts





IV. Summary

Slide15:Pancreas,H&E

likethesalivaryglands,noticeorganizationintoof

pancreas(compoundacinar)intolobules,separatedbyCTsepta;however,notice

thelackofconspicuousstriated(intralobular)ductsinthelobulesaswereseen

inthesalivaryglands





IV. Summary


pancreasisdividedintoexcretoryandendocrineportions:

Darkcells=secretoryacini (excretory)

Lightclustersofcells=Pancreaticislets (endocrine)(IsletsofLangerhans)





IV. Summary


intralobular excretoryduct(onlyonetypeofintralobularduct,unlikeinsalivaryglands)

pancreaticisletorisletofLangerhans(endocrine)

Secretoryacini(exocrine)





IV. Summary


secretoryacinus

serous acini of the exocrine pancreas have 5‐10 cells facing central lumen; apical ends areeosinophilic due to secretory granules; basal ends are basophilic due to nucleus and rER





IV. Summary

Slide24:Liver&GB,MassonTrichrome

largerspaces=portaltriads

smallerspaces=centralveins





IV. Summary

bileduct

hepaticartery

portaltriad

Slide141:Liver,H&E





IV. Summary

PortalTract/Triadhepaticportalvein

bileduct

hepaticartery

Slide141:Liver,H&E





IV. Summary

Slide24:Liver,MassonTrichrome

centralvein

hepaticlobule





IV. Summary

Slide29:Liver,H&E

portaltriad

centralvein





IV. Summary


hepatocytes

Kupffer cell(macrophage)insinusoid

hepaticsinusoidslinedbyendothelialcells





IV. Summary


lipofuscin





IV. Summary

Slide94:Gallbladder,Trichrome

mucosa

serosaonfreesurface;

coveredbyadventitiawhereboundbyliver

muscularis

laminaproprialumen

note the lack ofmuscularis mucosae and submucosa;the lamina propria is directly on the muscularis layer





IV. Summary

mucosalfold/ruga:transientfoldsofmucosa;disappearwhengallbladderisfull






IV. Summary

simplecolumnarepithelium,withNOgobletcells

verythinbasementmembrane






IV. Summary

Slide105:Gallbladder,H&E

epithelium

laminapropria

muscularis

serosa/adventitia





IV. Summary

Gallstones





IV. Summary

EMstoExamine

Fig16‐4:SerousandmucouscellsFig16‐10:PancreaticacinarcellsFig16‐14:Hepatocytes,perisinusoidal space,andbilecanaliculiFig16‐20:Gallbladder





IV. Summary

Common Confusion:Parotid gland vs. Pancreas

Slide 132, Parotid Gland

Parotid Gland:major salivary gland located in front of ear;almost exclusively serous cells that produce a thin waterysecretion rich in enzymes (e.g., amylase)

Look for: (1) striated (intralobular) ducts are readilyvisible; (2) surrounded by CT capsule with defined septa;(3) adipocytes may be present between lobules

Pancreas: exocrine and endocrine gland located in upperleft of abdomen; exocrine portion is purely serous andempties into the duodenum

Look for: (1) pale‐staining pancreatic islets (endocrine);(2) ducts are fewer and less readily seen; (3) surroundedby loose CT or very thin capsule with delicate septa; (4) athigher magnification, pale‐staining centroacinar cells(where duct inserts into acinus) may be seen

Slide 44, Pancreas





IV. Summary

Common Confusion:Pancreas vs. Spleen

Pancreas: exocrine and endocrine gland located in upperabdomen; exocrine portion is purely serous and emptiesinto the duodenum

Look for: (1) exocrine gland, so ducts are present; (2) pale‐staining pancreatic islets (endocrine) have homochromaticappearance; (3) at higher magnification, cells arranged inacinar configuration

Spleen: highly‐vascular abdominal organ with abundantlymphoid tissue; filters the blood, providing immunefunctions and removal/destruction of old or faulty redblood cells

Look for: (1) no exocrine tissue, so lacks ducts; (2) whitepulp has heterochromatic staining, e.g., pale germinalcenters surrounded by dark mantle zone; (3) no acinipresent; (4) numerous trabeculae

Slide 68, Spleen

Slide 154, Pancreas

Lab 16 Glands Digestive Glands Introduction 16 –Digestive Glands A560 –Fall 2015 I. Introduction...

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