Cause of vasodilatation in spider nevi -

Ans. is 'a' i.e., Estrogen Spider nevi refer to dilated, visible small blood vessels in the skin.- It is called spider nevi because it consists of central "feeding" blood vessel with numerous fine radiating legs emanating from the central body.Spider nevi are caused due to vasodilatation of vessels and are usually associated with cirrhosis.Cirrhosis is associated with vasodilatation and hyperdynamic circulation."The cause of vasodilatation in cirrhosis is uncertain but it is believed to be related to the increased level of estrogen in the body. Estrogen is a female sex hormone which is metabolized by liver. Thus in liver diseases its level tends to increase which is believed to cause vasodilatation, resulting in spider naevi.