1. Glandular Epithelium

2. Glandular Epithelium
• Glandular Epithelium: epithelium of cells
specialized to produce secretion. All
glands are of composed of epithelium.
• Secretion – Exocytotic release of
products, not metabolic wastes
• Molecules to be secreted may be stored in
membrane bound secretory granules
(vesicles)

4. Gland Categories
A) Presence or absence of ducts
• Exocrine – ducted
• Endocrine - ductless
B) Uni- or multicellular
C) Mode of secretion
D) Secretion products

7. Gland Categories
1) Exocrine - glands that exude secretions
into a ductule system. Have two parts,
acinous = secretory bulb and ductule.
2) Endocrine - glands exuding secretions
directly into body fluids, ultimately blood.
3) Mixed - glands combining both the above
characteristics (e.g. liver) in the same cell
4) Paracrine - tissue secretions affecting
own cells

8. Cellular Composition
1) Unicellular - single cell gland, Goblet cell;
mucous secreting. GI tract, respiratory ducts.
Secretion process alters cell and nucleus shape.
2) Multicellular -
a) intra epithelial gland -
gland is entirely within a layer of epithelium.
Common in pseudostratified columnar epith.
b) extra epithelial gland - in CT below epithelium; may
have different shapes; tubular and saccular (acinar).

10. Mucous Secretory Gland
Esophagus

11. Modes of Secretion
(how products leave the cell)
1) merocrine - secretion does not affect the
well-being of the cell = sweat glands.
2) apocrine - small part of the cell cytoplasm is
lost with the secretion; the cell is damaged
but not killed = mammary glands.
3) holocrine - great deal of cytoplasm is lost with
the secretion; the cell dies. Sebaceous
glands.

12. Apocrine Secretion
Mammary Gland

13. Epithelial Polarity
Absorption Secretion

14. Secretion Products
1) serous - thin, watery fluid, product of serous
cells, small pink staining cuboidal cells with
spherical to elliptical nuclei; salivary glands,
sweat glands, pancreatic acinar.
2) mucous - thicker, viscous secretion, product of
mucous cells, large blue staining cuboidal
cells with flat, elongate nuclei; GI tract, oral
cavity.
3) mixed serous-mucous - oral cavity, salivary.
4) sebaceous - thick, lipid rich secretions of
cuboidal cells in certain skin regions - face,
nose, axillary and pubic regions.

15. Serous (pancreatic acinar) cell

16. Myoepithelium
• Myoepithelium - specialized squamous
epithelial cells with powers of contraction;
• Surround glandular acini and ducts of
many glands,
• Contain actin, myosin, cytotokeratin =
definitely epithelial in origin, not muscle.

17. Myoepithelial Cell
In Salivary Gland

18. Diffuse Neuroendocrine System
(DNES)
• Paracrine secretion of norepinephrine or
serotonin in non-endocrine tissue
• Derived from Neural Crest Cells
• About 35 types of cells in a variety of
tissues such as respiratory, urinary,
gastrointestinal, pituitary, thyroid
• System formerly known as APUD cells
– Amine Precursor Uptake Decarboxylation

19. DNES Cell
With Secretory Granules

20. Secretory Membranes
• Similar names of secretion products;
names based upon type of secretions; form
organs (peritonea, gut tube lining, etc.)
1) Serous Membrane - thin, flat layer of squamous
epithelial cells which is moistened by exudates from
underlying blood vessels.
2) Mucous Membrane - moist epithelial surface,
usually columnar, but may be cuboidal or squamous,
that is moistened by secretions produced by glands
formed by the epithelium itself.