Glandular Epithelium

1. Glandular Epithelium

2. Glandular Epithelium • Glandular epithelium is more complex and varied than the epithelial cells which cover surfaces or line tubules or vessels.

3. Glandular Epithelium • Glandular epithelium is more complex and varied than the epithelial cells which cover surfaces or line tubules or vessels. • Glandular epithelium form glands which can consist of one or more cells that make and secrete a product.

4. Products • Water soluble protein

5. Products • Water soluble proteins • Nonpolar lipids or steroids

6. Classification • Glands are classified first based on the presences or absence of a duct for the secretory products.

7. Endocrine Glands • Are ductless glands • Secrete their products directly into the capillaries.

8. Exocrine Glands • secrete their products onto a body surface or a cavity.

9. Exocrine Glands • secrete their products onto a body surface or a cavity. • are classified first based on cell number

10. Unicellular Exocrine Glands • are made of up of single cells which secrete their products directly through exocytosis onto a surface.

11. Unicellular Exocrine Glands • are made of up of single cells which secrete their products directly through exocytosis onto a surface. • The only major examples are the goblet cells and mucous cells

12. Unicellular Exocrine Glands • found mixed with the columnar epithelium in the digestive and respiratory tracts. • They secrete products called mucins (mucous), glycoproteins that lubricate.

13. Multicellular Exocrine Glands • are made up many cells and are composed of two parts.

14. Multicellular Exocrine Glands • are made up many cells and are composed of two parts: • A epithelial lined duct • A secretory unit called the acinus

15. Multicellular Exocrine Glands • Supportive connective tissue surrounds the secretory unit and provides blood vessels and nerve fibers.

16. Multicellular Exocrine Glands • Supportive connective tissue surrounds the secretory unit and provides blood vessels and nerve fibers. • The shape of the duct and of the secretory unit provides for another level of classification.

17. Duct Structure • Simple- unbranched, straight duct

18. Duct Structure • Simple- unbranched, straight duct • Compound- branched duct

19. Secretory Unit: • Tubular- if the secretory unit has the same diameter throughout like a tube

20. Secretory Unit • Tubular- if the secretory unit has the same diameter throughout like a tube • Alveolar- if the secretory unit is in the shape of a flask • both of these terms refer to the acinus or secretory unit.

22. Examples

24. Method of Secretion • Glands regardless of type (unicellular or multicellular) can have one of two types of secretory processes:

25. Method of Secretion • Glands regardless of type (unicellular or multicellular) can have one of three types of secretory processes: • Merocrine- products are secreted by exocytosis. This is seen with most glands.

26. Method of Secretion • Glands regardless of type (unicellular or multicellular) can have one of three types of secretory processes: • Merocrine- products are secreted by exocytosis. This is seen with most glands • Holocrine- the cell ruptures and releases the product. New cells replace the spent cells.The only example in humans are the sebaceous (sweat) glands

27. Method of Secretion • Apocrine-the top of the cell pinches off. Possibly seen in the lactating mammary gland although this is generally considered merocrine in nature.