MMB (014, 015) Practical of Skeletal Muscle Histology Flashcards
Collagen type of Reticular fibers ?
collagen III
Name the stain used ,, and the fibers shown
-silver stain (black) ;
- Reticular fibres (collagen III)
What cells synthesize Reticular fibers ?
special fibroblasts called reticular cells
What is reticular connective tissue?
A type of connective tissue with a network of reticular fibres, made of collagen III
Are Reticular fibres unique only to reticular connective tissue ?
no , but only in this type they are dominant
Role of Reticular fibers in skeletal muscle support ?
The reticular fibres in the endomysium → mechanical support for the individual muscle cells
Other sites of reticular connective tissue ?
- Supporting framework for soft organs like the spleen, liver, lymph nodes, and bone marrow
Define the tissue type an the fibers surrounding it
- Adipocytes surrounded by reticular fibres.
-On a reticulin stain, each adipocyte is outlined by reticulin (arrow)
Are the arterioles surrounded by reticular fibres?
Yes
What type of muscle is the external anal sphincter made of?
• Voluntary
• Skeletal muscle
B. muscle spindle
• Which muscle cell organelle of is responsible for calcium storage?
sarcoplasmatic reticulum
•Variation in muscle fiber size
•Expansion of the endomysium by collagen
Duchenne muscle dystrophy :
Extensive replacement of muscle by fat cells
1- What is the nature of this disease?
An autoimmune disease.
2- Mention the Pathogenesis.
Autoantibodies directed against acetylcholine “nicotinic” receptors. These antibodies impair Neuromuscular transmission with resultant muscle weakness.
3- Mention the treatment
Cholinesterase inhibitors
1- What is your Diagnosis?
Duchenne Muscle Dystrophy
2- Describe the microscopic picture.
Marked variation in myofibers size, and endomysial fibrosis
3- What is the IHC stain used in this case? Please interpret its results as shown in the figure.
Dystrophin IHC stain ;
Absence of the normal sarcolemmal staining (negative)
4- Mention the difference between DMD and BMD.
BMD is generally milder than DMD, and the onset of symptoms usually occurs later Dystrophin levels in BMD are generally 30-80% of normal, while in DMD, the levels are less than 5%
