Epithelial Glands Flashcards
How do glands originate?
A proliferation of cells that will start moving inside the connective tissue below, from the epithelia.
During development, there will be differentiation with the part that secretes substances and the part that helps secreted substances release outside.
There is an increase in blood vessels to promote transfer of substances in the blood circulation.
What are exocrine glandular epithelia classified by?
Location
Cell number
Shape of secretory units
Presence of absence of branching
What are the 2 classifications for location of exocrine glands?
Intraepithelia - completely localized within a lining epithelium of an organ, can be unicellular or multicellular.
Extraepithelial - extends past the epithelium into the underlying tissue, always multicellular.
Describe goblet cells. Where are they found?
An unicellular exocrine gland.
They are found in the lining epithelia of respiratory and intestinal epithelium, and produce a secret mainly formed by sugars.
What are goblet cells stained by? How do they look
PAS can be used to mainly stains sugars. Goblet cells are seen to be filled with glycoprotein granules.
Sugars are also visible on top of epithelium where there is microvilli covered by glycocalyx.
The cell also presents a nucleus squeezed at the bottom with cytoplasm filled with mucin granules.
What are the 2 types of mucin granules?
Secreted - glycoproteins that will bind with water and form a protective layer on epithelium.
Associated to the PM - contributes to the protective layer as well as acts as signal molecules. They form the glycocalyx.
Describe mucin producing cells when cancerous.
Mucin producing cells are particularly aggressive when cancerous.
They can leave the epithelium and reach the blood vessels to metastasize.
In the diagnostic test for carcinoma, a type of mucin is recognized as a tumour marker.
Describe features of multicellular exocrine glands.
Produce various substances - secrete.
Released on the surface through 1 or more ducts.
Secretory cells are normally found in structures called adenomere.
An exocrine gland is formed by 1 or more adenomero.
When does the epithelium become a secretory epithelial?
Almost all types of cells have the ability to synthesize and secrete various kinds of molecules.
When these activities become the function of specialized cells with epithelial organisation, the epithelium becomes a secretory epithelial.
Describe the general structure of cells in large glands.
In large glands the set of epithelial cells is called parenchyma (the secreter), the surrounding connective tissue is called stroma.
