1. GLANDS
Dr. Safaa

2. Glandular Epithelium
A gland is one or more cells that makes and secretes an aqueous fluid
Both endocrine and exocrine glands are developmentally derived from epithelia, which form a down-growth into the underlying connective tissue.

3. Exocrine - Endocrine

4. Glandular Epithelium
Two types of glands formed by the infolding (invagination) of epithelium:
Endocrine:
Ductless
No contact with exterior of body
Usually produce hormones (pituitary, thyroid, adrenals, pancreas)
Secretions enter directly into blood vessels
Exocrine:
Open to exterior of body via ducts (sweat glands, pancreas , sebaceous glands, salivary glands)

5. glands Classification of Endocrine
Two types of endocrine glands can be recognized based on the arrangement of their cells:
Cords interspersed between dilated blood capillaries eg, adrenal gland, parathyroid, anterior lobe of the pituitary.
Vesicles or Follicles filled with noncellular material eg, the thyroid gland.

6. Exocrine glands Exocrine glands have:
A secretory portion, which contains the secretory cells responsible for the secretory process.
Ducts, which transport the secretions.

8. Types or Classification of Exocrine Glands
According to the number of cells:
Unicellular: goblet cells
Multicellular: e.g sweat gland, sebaceous glands salivary glands.
According to the branching of the duct:
Simple ‒ unbranched duct
Compound ‒ branched duct
According to the secretory part:
Tubular cells organize as tubules
Acinar or alveolar the cells organize as spherical or globular units

10. Multicellular Glands with an unbranched excretory duct are called simple:
Simple tubular e.g intestine.
Simple coiled tubular e.g sweat glands.
Simple branched tubular e.g stomach.
Simple acinar e.g urethra.
Simple branched acinar e.g sebaceous glands.

16. Multicellular glands with branched excretory duct are called compound glands:
Compound branched tubular e.g duodenum.
Compound acinar e.g .pancreas.
Compound tubuloacinar e.g . submandibular salivary gland.

18. Multicellular Exocrine Glands

24. According to how the secretory products leave the cell:
Merocrine
Apocrine
Holocrine

25. Exocrine glands Classified by method of secretion: Merocrine Apocrine
Holocrine

26. Merocrine
Secrete products by exocytosis
Cell membrane intact
No loss of cell substance
E.g Sweat gland, pancreas

29. Apocrine
Secrete products with part of the cytoplasm and cell membrane lost.
The continuity of the plasma membrane is restored by the fusion of the broken edges of the membrane.
Mammary gland ,apocrine sweat glands, and the prostate

32. Holocrine Secrete products by rupture of cell membrane
Breakdown and discharge of the entire secretory cell.
Whole cell dies, replaced by new cell
It is only seen in the sebaceous glands of the skin.

35. According to type of secretion
Serous – watery secretion
Mucous – viscous secretion
Mucoserous – mixed secretion

36. THANK YOU