How does smooth muscle control the vascular system?
Regulation of blood pressure
How does smooth muscle control airways?
Constriction and relaxation
How does smooth muscle control GI tract?
Peristalsis, segmentation, and transit
How does smooth muscle control the gallbladder and urinary bladder?
Storage and emptying
How does smooth muscle control the uterus?
Accommodation and delivery
Difference between skeletal and smooth muscle
Skeletal muscle has sarcomeres and striations, smooth muscle does not
Which is faster, skeletal or smooth muscle?
Skeletal muscle (0.2s vs smooth muscle 70s)
Which uses less energy, skeletal or smooth muscle?
Smooth muscle (1.2umol vs skeletal muscle 50umol)
Difference in release of calcium in skeletal vs smooth muscle
Skeletal: T-tubules to quickly propagate AP, calcium released
Smooth: calveoli (invaginations) propagate AP. triggers calcium release
3 types of calcium channels in smooth muscle
Voltage gated
Ligand gated
IP3 gated
How is calcium removed after contraction?
Removed by Ca-ATPase
How are thick filaments regulated in smooth muscle?
ACh binds M3 receptor, calcium channels opened. Calcium binds to calmodulin which binds to MLCK, complex regulates thick filaments
Explain length-tension curve
As you increase muscle length, you increase muscle output, but only up to a certain point. Then muscle becomes too stretched.
Explain pressure-volume curve
Similar to length-tension (pressure = force output, volume = length)
Explain force-velocity curve
Increase in force (due to heavy load) decreases velocity
Phasic contraction
Periodically contracts and relaxes
Ex: proximal portion of stomach to move food down the tract
Tonic contraction
Is relaxed and then contracts for a long time
Ex: sphincters of GI tract
