(٢)Glandular
• It is a modified type of
epithelial tissue
specialized in
• production of secretions.
• It is classified :
1- According to the duct.
2- According to the
secretory part.
3- According to nature of
secretion.
4- According to mode of
secretion.
epithelium
I- According to the duct
* Exocrine glands: possess ducts e.g. salivary glands
I- According to the duct
* Endocrine glands: have no ducts and the secretion
pass directly to the blood e.g.
Thyroid G.
Pituitary G.
Adrenal G.
I- According to the duct
• * Mixed glands: have the two types e.g.
Pancreas
(B) Branching of the duct:
* Simple glands possess one unbranched duct
e.g. intestinal,
gastric glands
(B) Branching of the duct:
• Compound glands
have branched duct
system
• e.g. salivary glands.
II- According to the secretory part.
(A) Number of cells :
• Unicellular glands: formed of a single cell
• e.g. goblet cells.
II- According to the secretory part.
(A) Number of cells :
• Multicellular glands:
formed of numerous cells
e.g. salivary glands,
pancreas
liver
II- According to the secretory part.
Shape of the secretory part :
• * Tubular glands: have
tubular secretory parts e.g.
intestinal glands and liver
• * Alveolar glands: have
alveolar (flask shaped) or
acinar (grape like) secretory
parts e.g. sebaceous and
mammary glands.
• * Tubulo-alveolar glands:
the secretory part is formed
of the two types e.g. salivary
glands and pancreas.
Branching of the secretory part:
• * Simple glands: have
unbranched secretory parts
e.g. intestinal glands.
• * Branched glands:
have branched
secretory parts e.g.
salivary glands,
•
liver and
•
pancreas.
III- According to nature secretion
• * Mucous glands: produce viscid mucous poor in
enzymes e.g. goblet cells and minor salivary glands.
• * Serous glands: produce watery solution rich in
enzymes e.g. Parotid glands and pancreas.
• * Mucoserous glands: produce both types of
secretions e.g. submanibular and sublingual glands.
• Sweat glands of skin produce watery secretion
containing some enzymes and waste products
• Oily glands: secrete fatty secretion e.g. sebaceous
and tarsal glands
• Waxy glands: secret waxy secretion e.g. ceruminous
glands of the external canal.
• Cellular glands: produce cells e.g testis and ovary
VI- According to method (mode) of secretion:
Merocrine glands : the secretory cells are not
destroyed during secretion e.g. salivary glands.
VI- According to method (mode) of secretion:
Apocrine glands : the apical part of the cells is
destroyed during secretion e.g. mammary
glands.
VI- According to method (mode) of secretion:
Holocrine glands: the whole cell is destroyed during secretion
e.g. sebaceous glands.
(3) NEUROEPITHELIUM
• Definition:
• A modified type of epithelial tissue
specialized for receiving of sensory stimuli.
(3) NEUROEPITHELIUM
• SITES:
Taste buds
Olfactory epith.
Organ of Corti
Crista ampularis
Macula sacculi,
utriculi