The primary cause for the development of shock following hemorrhage is
Marked vasodilation
Decreased blood volume
Inadequate output by the hea
Obstruction to blood flow
Hemorrhage is the most impoant cause of hypovolemic shock. There will be reduction in the venous return leading to a fall in cardiac output and BP. The severity of shock depends upon the rapidity of blood loss. Ref: Textbook of medical physiology by N Geetha, 3rd edition, page no. 204
Cardiovascular system