Smooth Muscle physiology Flashcards
Unitary Type
lg sheets connected by gap junctions that have waves of contraction (contract as one unit)
multi-unit
no electric connection, individual stimulation
actin structure
NO troponin; just tropomyosin
myosin structure
slow ATP-ase activity
Actin-Myosin Structure
long filaments on periph of cell, inc ratio
SR structure
No t-tubules!
tonic contraction
prolonged
phasic contraction
cyclic
Length-Tension
varies over hours, “L-adaptation”
changes in contractile unit #s
Force-Velocity
depends on load
Velocity Slower, affected by phosphor of MLC
reg by: x-bridge rate and # of bridges
Intestinal ANS effect
PNS: +mem. potential, +contraction
SNS: - mem potential, + relaxation
Lungs ANS
PNS: + contraction
SNS: +B-adrenergic, +relaxation
Blood Vessel ANS
SNS: +A-adrenergic, +constriction
Relaxation Regulation
- Ca Channels, + K channels
+cGMP, - kinases, +MLCP
+cAMP, +B-and, -MLCK, -MLC, -contract
what happens in relaxation?
SERCA activated, MLCP dephosph MLC
