Comparison between tract and nerve

-
  Comparison between tract and nerve Nerve Nerve contain bundle of axons (nerve fibers) in the peripheral nervous system (PNS) that transmits signals between the central nervous system (CNS) and other parts of the body. It is the most important part of peripheral nervous system Location: Peripheral nervous system. Structure: Made of axons, connective tissue layers (endoneurium: axon is surrounded by it , perineurium: bundle of axons are surrounded by it, epineurium: whole nerve trunk is surrounded by it), and blood vessels. It gets myelination by Schwann cell   Function: Carries sensory signals to the CNS (afferent) from peripheral part of body or motor signals carry from from the CNS (efferent) to target organs like skeletal muscle, cardiac muscle, smooth muscle or glands Example: Sciatic nerve, median nerve, except optic nerve (though optic nerve is technically part of CNS in develop...
Post a Comment

Difference between parotid and submandibular gland

-

 




Difference between parotid and submandibular gland


Histology of Parotid Gland

Type: Purely serous gland : produces watery like secretion which  rich in enzymes

Histological Features:

    • Capsule & Septa: parotid gland is surrounded by a fibrous capsule, which extends into the gland forming septa, dividing it into lobules.
    • The Secretory Units of parotid gland is composed entirely of serous acini which is  darkly stained, pyramidal-shaped cells with round nuclei, and basophilic cytoplasm due to rough endoplasmic reticulum (RER). It secrete amylase (digestion of carbohydrates) and antimicrobial proteins (lysozyme, lactoferrin).
  • Duct System of parotid gland : types of ducts
    • Intercalated ducts: it is lined by simple cuboidal epithelium.
    • Striated ducts: it is larger, lined by simple columnar epithelium, and have basal striations due to mitochondria (for ion transport).
    • Excretory ducts: it is lined by stratified columnar epithelium and open into the oral cavity.
    • Fat Cells: it is an unique feature: Adipose tissue often present in older individuals.

Histology of Submandibular Gland

Type: Mixed gland  it produces both serous and mucous secretion, but predominantly serous secretion

Histological Features:

    • Capsule & Septa: like  the parotid gland, it has a fibrous capsule that extends into septa dividing the gland into lobules.
    • Secretory Units: it has predominantly serous acini (~80%): Dark-stained, round nuclei, basophilic cytoplasm. Mucous acini (~20%) are light-stained, flattened nuclei at the basal region, producing mucin.
    • Serous demilunes (crescent-shaped serous cells on mucous acini like half moon ): Secrete lysozyme.
  • Submandibular gland has extensive duct System: types of submandibular gland
    • Intercalated ducts: Shorter than in the parotid gland.
    • Striated ducts: More prominent than in the parotid, contributing to ion modification.
    • Excretory ducts: Larger, lined by stratified columnar epithelium.

 

Parotid gland

Submandibular gland

Purely serous salivary gland

Both serous and mucous acinus is present

Contain adipose tissue

Usually contain no adipose tissue

Duct system is not extensive

Duct system are extensive

Serous demilunes are not  present

Serous demilunes are present

Comments

Post a Comment

Popular posts from this blog

Difference between relations of right and left suprarenal gland

-
Difference between relations of right and left suprarenal gland Topics Right suprarenal gland Left suprarenal gland Anterior surface Medial inferior vena cava Lateral right lobe of liver including bare area Superior stomach Inferior splenic artery & pancreas Posterior surface Inferior kidney Superior right crus of diaphragm Medial crus of left diaphragm Lateral kidney Medial border Right celiac ganglion Right inferior phrenic artery   Left   celiac ganglion Left   inferior phrenic artery Left gastric vessels Hilum Near the upper end Near the lower end Peritoneal relations Not related with peritoneal except a tiny area below Related to peritoneum of omental bursa which separates it from stomach
Read more

Fibroblast vs fibrocyte

-
  Fibroblast  is permanent  connective tissue cell responsible for the production of the extracellular matrix (ECM) and collagen fibers which  are essential for tissue structure and repair and play a major role in wound healing. unique features of Fibroblasts : Shape and Structure :  Spindle-shaped (elongated). it contain l arge nucleus that is oval or elliptical . and c ytoplasm is abundant and basophilic (stains blue), reflecting active protein synthesis. and it has  prominent nucleolus , indicating high activity in protein synthesis. Function : it produces the structural components of the extracellular matrix like collagen , elastin , glycosaminoglycans , and proteoglycans .  In response to injury, fibroblasts proliferate and migrate to the site of injury, secreting growth factors and ECM components to promote tissue repair and fibrosis. Major producer of collagen fibers which provide tensile strength to tissues. Elastin Production : ...
Read more