P3, M2, D1.
Smooth Muscle
Structure and ultra-structure:
Definition:
Smooth muscle is muscle tissue in which
the contractile fibrils are not highly
ordered. It is located in the wall of the GI
tract, the walls of arteries and veins and
even around glands. It is also found in
other internal organs.
This type of muscle is not under voluntary
control.
(MedicineNet, n.d.)
Cell shape:
Type of contraction:
Unlike cardiac and skeletal muscle,
smooth muscle does not contain the
calcium-binding protein troponin.
Contraction is initiated by a calcium-
regulated phosphorylation of myosin,
rather than a calcium-activated troponin
system.
The contractions of smooth muscle are
slow and sustained.
1
Smooth Muscle
Structure and ultra-structure:
Definition:
Smooth muscle is muscle tissue in which
the contractile fibrils are not highly
ordered. It is located in the wall of the GI
tract, the walls of arteries and veins and
even around glands. It is also found in
other internal organs.
This type of muscle is not under voluntary
control.
(MedicineNet, n.d.)
Cell shape:
Type of contraction:
Unlike cardiac and skeletal muscle,
smooth muscle does not contain the
calcium-binding protein troponin.
Contraction is initiated by a calcium-
regulated phosphorylation of myosin,
rather than a calcium-activated troponin
system.
The contractions of smooth muscle are
slow and sustained.
1
