20: Peripheral circulation and regulation of flow Flashcards
MAP
CO x TPR
How to changes in TPR occur
mechanisms intrinsic or extrinsic to vascular smooth muscle
Characteristics of smooth muscle
Slower to relax/contract
Develop active tension over a longer range of lengths
activated by stretch
ability to swoon the ladies much better than other muscle
What initiates smooth muscle action potential
Ca influx
What does calcium calmodulin do
Activate myosin light chain kinase
What does myosin light chain kinase do
phosphorylates myosin light chains in the presence of ATP
What happens when MLC are phosphoylated
cross bridge formation
What causes MLCK dephosphorylation
Decreases in intracellular Ca
What effect does vasodilators have on Ca
increase cGMP which inhibits Ca
What effect does B-2 receptor binding have on Ca
increases CAMP which triggers Ca transfer to extracellular space
What does norepinephrine from sympathetics bind to
alpha adrenergic receptors
How are intrinsic mechanisms related to CNS and hormonal regulation
Intrinsic are independent of CNS and hormones
when does coronary flow occur on the left side of the heart
diastole
Nitric oxie
Vasodilator
increase cGMP
Endothelin
Vasoconstrictor
