Vascular System

Layers of Arteries

Layer Elastic Artery Muscular Artery Arteriole
Tunica adventitia + + +
External elastic layer - Elastin -
Tunica media Elastin Smooth muscle Smooth muscle
Internal elastic layer - Elastin -
Tunica intima + + +

LaPlace's Law

Parameter γ ∝ P × R ÷ T
γ Surface tension
P Pressure difference
R Radius
T Thickness

Hormones Acting on Vessels

Hormone Receptor Effect
Norepinephrine α1 Vasoconstriction
Epinephrine β2 Vasodilation
  α1 Vasoconstriction
Dopamine D1 Vasodilation
  α1 Vasoconstriction
Serotonin 5-HT1 Vasodilation
Vasoconstriction
  5-HT2 Vasoconstriction
Histamine H1 Vasodilation
Angiotensin AT1 Vasoconstriction
Vasopressin V1 Vasoconstriction
Adenosine A1 Vasodilation
Prostaglandin PGE1 Vasodilation
Prostacyclin PGI2 Vasodilation
Thromboxane TXA2 Vasoconstriction
Endothelin ETA Vasoconstriction
Bradykinin B1 Vasodilation
Substance P NK1 Vasodilation
Nitric oxide - Vasodilation