Vascular Smooth Muscle

Question 1

Medial layer in artery
Venous
Pre-cap sphincter

Answer 1

Regulates peripheral resistance and BF

Venous return and CO

Cap blood flow

Question 2

Vascular contraction vs. skeletal

Answer 2

Slower and sustained duration

Question 3

SMooht muscle contraction

Answer 3

Sponaneous electrical activity

NT

Hormones
Chemicals

Stretch

Question 4

Cross bridge cycle insmooth muscle

Answer 4

Myosin dependent

Ca binds calmodulin…activiates myosin light chain phosphorylase…this phosphorylates the myosin

Phosphrylation allows for sustained contraction

Question 5

Latch-bridge

Answer 5

Using minimal ATP in order to maintain tone

Question 6

Myosin phosphatase activity regulation

Answer 6

Can be inhibited by RHo kinase and others

This enahcnes sensitivity of myosin to Ca

Question 7

Explain molecularly what happens in smooth muscle regulation

Answer 7

See diagram in notes

Question 8

Smooth muscle relaxation

Answer 8

GTP to cGMP or ATP to cAMP…this activates a protein kinase which can dec calcium

Phosphodiesterase degrades the cGMP…viagara inhibits this

Question 9

NItroglycerin

Answer 9

Release NO in coronary artery smooth muscle….activate soluble GC….cGMP…relax spasmed coronary artery…relieves chest pain