Smooth Muscle Contraction Flashcards
Where is smooth muscle found
In walls of organs such as liver,intestines,pancreas
Anatomy of smooth muscle
-single nucleated
-fat in the middle skinny sat the end
-non striated
-function dependent
Smooth muscle cells
Spindle shaped (fusiform) and contain just one,
centrally located nucleus per cell
Not striated (hence “smooth”)
A lot found in GI tract (circular muscles) Mesh together
Smooth muscle contraction
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Excitation-contraction coupling
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What are skeletal muscles stimulated by
Solely electrical stimulation
What are smooth muscle sarcomere are bordered by
Dense bodies
Cross bridge activation in smooth muscle
-calcium enters and binds to calmopdulin
-calciumcalmodulin bind to myosin light chain kinase
Atp is hydrolysed and phosphate is released
What filaments does smooth muscle contains
Actin and myosin just like skeletal and cardiac muscle
What parts does smooth muscle has
No troponin,calmodulin and myosin light chain kinase
What are the sources of calcium in smooth muscle
SR and extracellular
Smooth muscle contraction
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Single unit smooth muscles
Whole muscle responds as a single unit Numerous gap junctions
Can be innervated by:
Nerves and hormones
Spontaneous electrical activity Local factors
Examples
Intestinal tract, uterus, small blood vessels
Multi-unit
Whole muscle responds in individual units
Few gap junctions
Can be innervated by:
Nerves and hormones
Examples
Large diameter blood vessels
What type of smooth muscle do air ways contain
Multi-unit smooth muscle
