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 lumbar and sacral splanchnic nerve

-
Difference between lumbar and sacral splanchnic nerve Name Location of preganglionic neuron Sympathetic ganglion Collateral Ganglion Form Autonomic   Plexus Fibres Functions Lumbar splanchnic nerve Lateral horn of gray matter of Lumbar 1,2 spinal cord segment Lumbar 1,2 Inferior mesenteric ganglion Superior hypogastric plexus Preganglionic Sympathetic Fibres and General visceral afferent fiber Innervate pelvic viscera and vasculature Sacral splanchnic nerve Lateral horn of gray matter of Lumbar 1,2 spinal cord segment Sacral 1-5 Inferior mesenteric ganglion Inferior hypogastric plexus Preganglionic and postganglionic fibres Sympathetic Fibres and General visceral afferent fiber The inferior hypogastric plexus is a plexus of nerves that suppli...
Read more

Difference between greater and lesser splanchnic nerve

-
Difference between greater and lesser splanchnic nerve  Name Location of preganglionic neuron Sympathetic ganglion Collateral Ganglion Form autonomic Plexus Functions Greater splanchnic nerve Lateral horn of gray matter of Thoracic 5-9 spinal cord segment Thoracic 5-9 Synapse with celiac ganglion Celiac plexus   The fibers in this nerve modulate the activity   of the enteric nervous system of the foregut. They also provide the sympathetic innervation to the adrenal medulla, stimulating catecholamine release. Lesser splanchnic nerve Lateral horn of gray matter of Thoracic 10-11 spinal cord segment Thoracic   10-11 Synapse with   aortico-renal ganglion or superior mesenteric ganglion Renal plexus The nerve modulates the activity of the enteric nervous system of the midgut
Read more

Difference between anterior and posterior part of rectus sheath Topics Anterior part of rectus sheath Posterior part of rectus sheath Above costal margin This part of rectus sheath is only formed by single aponeurosis. The aponeurosis of External oblique abdominis No rectus sheath Related with costal cartilage From costal margin to arcuate line This part of rectus sheath is formed by two aponeurosis. The aponeurosis of External oblique abdominis and anterior layer of aponeurosis of internal oblique abdominis This part of rectus sheath is formed by two aponeurosis. The aponeurosis of External oblique abdominis and posterior layer of aponeurosis of internal oblique abdominis Below the arcuate line (this line is situated midway between umbilicus and upper surface of pubis symphysis ) This part of rectus sheath is formed by three aponeurosis. The aponeurosis of External oblique abdominis, internal oblique abdominis and transverses abdominis No rectus sheath Related with fascia transversalis

-
Difference between anterior and posterior part of rectus sheath Topics Anterior part of rectus sheath Posterior part of rectus sheath Above costal margin This part of rectus sheath is only formed by single aponeurosis. The aponeurosis of External oblique abdominis  No rectus sheath Related with costal cartilage From costal margin to arcuate line This part of rectus sheath is  formed  by two  aponeurosis. The aponeurosis of External oblique abdominis  and anterior layer of aponeurosis of internal oblique abdominis This part of rectus sheath is  formed  by two  aponeurosis. The aponeurosis of External oblique abdominis  and posterior layer of aponeurosis of internal oblique abdominis Below the arcuate line (this line is situated midway between umbilicus and upper surface of pubis symphysis )  This part of rectus sheath is formed by th...
Read more