10/8/2008
Glandular Epithelia/
Glands
Helpful Vocab
• Gland- consists of one or more cells that
make and secrete (export) a particular
product.
• Secretion- the passage of material formed
by a cell to its exterior
• Ducts- a canal passageway; a tubular
structure that provides an exit for the
secretions of a gland, or for conducting
any fluid
Epithelia Glands
•
Epithelial cells are specialized cells. They protect cells
below them and may also carry out special functions.
(Not found in book)
• Epithelia Glands are a membranous tissue composed of
one or more layers of cells separated by very little
intercellular substance and forming the covering of most
internal and external surfaces of the body and its
organs.(Not found in book)
• Glandular Epithelia contains two different types of
glands.
- Endocrine Gland and
- Exocrine Gland
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Endocrine Glands
•
Also called ductless Glands
- Which means glands eventually lose their ducts
• The Endocrine Glands internally secrete their products.
• This gland produces hormones
- The hormones enter into the blood or lymphatic
fluid and travel to specific target organs.
• The Gland is structurally diverse, so one description
doesn’t fit all.
- Most Endocrine glands are compact Multicellular
organs.
- Some individual hormone-producing cells are
scattered in the digestive tract mucosa and in the
brain.
Exocrine Glands
• This gland is far more numerous than Endocrine
Glands, many of their products are familiar.
• This gland secrete their products onto the body
surface or into body cavities
• These glands are very diverse.
- They include the mucous, sweat glands, oil,
the salivary glands, the liver, the pancreas,
and many others.
• The Exocrine Glands include:
- Unicellular Exocrine Gland and
- Multicellular Exocrine Gland
Unicellular Exocrine Glands
• The only important example of unicellular gland
is the goblet cell.
• Goblet Cells are sprinkled in the epithelial
linings of the intestinal and respiratory tracts
amid columnar cells with other functions.
• In humans, all such glands produce Mucin.
-Mucin is a complex glycoprotein that
dissolves in water when secreted.
*Mucin forms mucus.
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Multicellular Exocrine Glands
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Multicellular Exocrine are more complex than Unicellular Exocrine
The Multicellular Exocrine contain two basic parts
- Epithelium-derived duct and
- Secretory Unit
Structural Classification
- Simple Glands- have an unbranched duct
- Compound Glands- have a branched duct
* From there the glands are categorized by their
Secretory Units
1.) Tubular- means that the secretory cells form tubes
2.) Alveolar (or Acinar) - means if the secretory cells form
small, flask-like sacs
3.) Tubuloalveolar- means that if they have both types of
secretory units
Multicellular Glands have two different modes of secretion
-Merocrine Glands- secrete their products by exocytosis as they are
produced
* Most Multicellular Glands are Merocrine Glands
- Holocrine Glands- accumulate their products within them until they
rupture
Simple and Compound Exocrine
Glands
Websites Used
• http://encyclopedia.farlex.com/glandular+e
pithelium
• http://www.thefreedictionary.com/glandular
+epithelium
• http://www.mc.vanderbilt.edu/histology/wor
d/2003/glandularepithelium03.htm
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