Smooth muscle Flashcards
Features of smooth muscle
Non striated
Synsitial
Normally around hollow viscarea
Features in a transverse section
Much smaller cells
Many more of cells
Nuclei in centre of the cell
Features in a Longitudal section
Not stripy
Located nucleus in centre
Small single Nucleated cell
Short tapering fibres
What initiates synsitial function
Gap junctions
What is caveole
Small indentations present in the cell membrane
Function of the structural proteins
Act as anchoring points for our thick and thin filaments
What do thin filaments have
Actin
Tropomyosin
No troponin
Will tropomyosin be over binding site
No as no troponin so actin can immediately bind and immediately forms a cross bridge
Why is calmodulin present
It is a molecule with a calcium binding site
How does calmodulin becomes activated
Calcium binds to the calmodulin, then the calmodulin binds to myosin light chain kinase and this phosphorylates the myosin molecule
What is the enzyme associated with calmodulin
Myosin light chain kinase
What happens if we phosphorylation myosin
A cross bridge can be formed which forms a contraction
In smooth muscle, does myosin head have ATPase acitvity
No
Why do we need to use enzyme myosin phosphate
Cross bridging cant occur as no ATP so cant make or break the cross bridge so enzyme is needed. So this enzyme dephosphorylates the myosin bringing it back to its resting state
Increase calcium causes
A increase in drive of activity
