LEARNING OBJECTIVES

3. LEARNING OBJECTIVES • DEFINE EPITHELIAM • TYPES OF EPITHELIAM • DEFINE GLAND • NAME PARTS OF GLANDS • CLASSIFY GLANDS dr.sikander05@gmail.com

4. Definition epithelium • Covering epithelium; covers the surface of organs ,line cavities, • Glandular ;form secretary parts of glands

5. Classification of Epithelial Tissues Based on: *number of layers *shape of cells

6. Classification of Epithelia • The morphology of the cells may be • squamous (flat), cuboidal, or columnar when viewed in sections taken perpendicular to the basement membrane. Stratified epithelia are classified by the morphology of the cells in their superficial layer only. In addition to these two major classes of epithelia, which are further identified by cellular morphology, there are two other distinct types: pseudostratifiedand transitional GI tract kidneys,lungs glands mouth, esophagus, vagina, anus respiratory system ducts of male reproductive system, interlobular ducts of liver; functions: protection and secretion) Relaxed, the outermost cells become bulbous Distended, the uppermost cells are stretched into a squamous shape epidermis of skin ducts of sweat glands, salivary glands, mammary glands; function: protection

7. GLANDS

8. GLANDS • A STRUCTURE CAPABLE OF SYNTHESIS,STORAGE AND RELEASE OF CHEMICAL SUBSTANCES.

9. Glands • Glands arise during fetal life from covering epithelia by means of proliferation and invasion of the epithelial cells into the subjacent connective tissue, followed by further differentiation • epithelial cells are the major component of all the glands of the body

11. According to duct system • Exocrine (Gr. exo, outside, + krinein, to separate) • glands retain their connection with the surface epithelium from which they originated. • This connection is transformed into tubular ducts lined with epithelial cells through which the glandular secretions pass to reach the surface.

13. Endocrineglands (Gr. endon, within, + krinein) are glands whose connection with the surface is lostduring development. These glands are therefore ductless, and their secretions are picked up and transported to their site of action by the bloodstream rather than by a duct system. .

15. Parts of gland • Exocrine glands have a secretory portion, which contains the cells responsible for the secretory process, and • ducts, which transport the secretions.

16. Based on number of cells • Unicellular-goblet cell • Multicellular -

17. Classification of multicellular glands • Based on branching of duct • Simple glandshave only one unbranched duct. • compound glandshave ducts that branch repeatedly.

19. simple glands • Simple tubular • Simple coiled tubular • Simple branched tubular • Simple branched acinar

20. Compound glands • compound branched tubular glands • Compound tubulo-acinar glands • Compound acinar glands

21. Simple glands can have their secretory portion in the form of a tubule, a coiled tubule, a branched tubule, or an acinus, in which the cells organize as spherical or globular units. • Compound glands can be tubular, acinar, or tubuloacinar

22. Example of an organ which is both exocrine and endocrine is • Liver • Uterus • Ovary • Testis • kidney

23. Simple tubular • This type of gland has a single, straight tubular lumen into which the secretory products are discharged • Intestinal glands

24. Simple coiled tubular • Consists of a single tube that is tightly coiled in three dimensions; portions of the gland are thus seen in various planes of section. • Sweat glands

25. Simple branched tubular • Each gland consists of several tubular secretory portions • wider diameter • Mouth , tongue and • esophagus

26. Simple branched acinar • Each gland consists of several secretoryacini • They empty into a single excretory duct • The excretory duct is formed by the stratified epithelium surrounding the hair shaft. • the secretory product, sebum, accumulates within the secretory cells and is discharged by degeneration of the cells. • Sebacous glands

27. compound branched tubular glands • The duct system is branched, thus defining the glands as compound glands and the secretory portions have a tubular form, • which is branched and coiled.Salivary glands • Brunner's glands of the duodenum,

28. Compound tubulo-acinar glands • Have three types of secretory units; namely branched tubular, branched acinarand branched tubular • The submandibular salivary gland . • It contains two types of secretory cells, mucus-secreting cells and serous cells. • Kidney and testis

29. Compound acinar glands • Those in which the secretory units are acinar in form and drain into a branched duct system. • The lined by simple cuboidal epithelium. • Mammary glands • pancreas

30. BASED ON SECRETIONS • MUCUS- • SEROUS • MIXED

31. Based on how the secretory products leave the cell • merocrine (Gr. meros, part, + krinein) In merocrine glands (eg, the pancreas), the secretory granules leave the cell by exocytosis with no loss of other cellular material. • holocrine(Gr. holos, whole, + krinein). In holocrine glands (eg, sebaceous glands), the product of secretion is shed with the whole cell—a process that involves destruction of the secretion-filled cells. • apocrine (Gr. apo, away from, + krinein) gland—the secretory product is discharged together with parts of the apical cytoplasm. sweat glands

32. THANKS