SALIVARY GLAND

SECRETION : Saliva.
In humans there are 3 major pairs of salivary glands they are:

• PAROTID
• SUBMANDIBULAR
• SUBLINGUAL
 
FEATURES OF SALIVARY GLAND

°It possesses a connective tissue capsule
°This connective tissue capsule send septa, which divides the glandular parenchyma into lobes and lobules
°Each lobule contain-
       *DRAINING DUCTS and
       *ACINI {SECRETORY UNIT}:

           They are of 3 types:

• SEROUS ACINI
      
     •Small with narrow lumen.
     •Lined by pyramid cells with round              basal nucleus.
      •Shows "Biphasic staining" with H&E          because apical part of serous cells            contain Zymogen granules which                stains eosinophilic where as base              part take basophilic staining.

•MUCOUS ACINI
      
      •Large with wide lumen.
      •Lined by Columnar cells with                      flattened basal nuclei.
      •Apical part of mucous cells is filled           with pale-staining mucous droplets.           As mucous doesnt take stain cells             looks empty.

•SEROMUCOUS ACINI
     
      •Contain both Serous and Mucous              cells.
      •Sometimes serous cells form                     "crescentic cap" on mucous acini             called "Serous Demilunes".

Courtesy :research gate
      

SALIVARY DUCT SYSTEM

°Acini opens into Intercalated duct.
°Intercalated ducts unite to form Striated ducts , both Intercalated and Striated ducts are "Interlobular".
°These excretory ducts unite to form main duct.

*Striated ducts are Striated because they have basal infoldings of plasma membrane and longitudinal orientation of mitochondrial between these infoldings which gives the striated appearance.

MUCOUS SALIVARY GLAND (SUBLINGUAL SALIVARY GLAND)
*Characterized by a large number of mucous acini .
*Poorly developed duct system.

SEROUS SALIVARY GLAND
(PAROTID SALIVARY GLAND)
*Large number of serous acini .
*Well developed duct system.

MIXED SALIVARY GLAND
(SUBMANDIBULAR SALIVARY GLAND)
*Presence of both Serous and Mucous acinus.
*Presence of "serious Demilune".
*Moderately developed duct system.

H&E slides 
MUCOUS SALIVARY GLAND (SUBLINGUAL SALIVARY GLAND)
SEROUS SALIVARY GLAND
(PAROTID SALIVARY GLAND) 




   MIXED SALIVARY GLAND
(SUBMANDIBULAR SALIVARY GLAND)
   



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