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...

Difference between osteoblast and osteoclast


Difference between  osteoblast and osteoclast 



Topics
Osteoblast
Osteoclast
Cell morphology
Cuboidal to low columnar, basophilic cytoplasm with clear area within cytoplasm due to presence of golgi complex  
Large irregular shaped cell
Cytoplasm acidophilic with ruffled border and underlying Howship’s lacuna
Nucleus
mononucleated cell ,
Multinucleated
Size
       15-30

150–200 µm in diameter
Location
Bone surface: in growing bone it is situated near the periosteum in adult boen : it is situated in the endosteal surface of bone,
Closing cone of resorption canals  
Bone surface , cutting cone of resorption canal
Percentage of all cells in the bone
Ø  5%
Ø  1%
Life span
Weeks (average 12 days)
Days > 3 days
Precursor cells
Osteoprogenitor cell
Hemopoietic cells
Differentiation process / transcription factors  
CBFA1 (RUNX2) IGF1
c-fos, NFkB,RANK-RANKL signaling
Major hormonal / regulatory receptors
RANKL, PTH receptors
RANK, calcitonin receptors, tartrate resistant acid phosphaste (TRAP) receptors
Biochemical markers
Osteocalcin , bone sialoprotein (BSP-2)
Tartrate resistant acid phosphatase (TRAP) cathepsin K , matrix metalloproteinase 9 (MMP-9)

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