True statements about shock-

Shock is the clinical syndrome that results from inadequate tissue perfusion. Irrespective of cause, the hypoperfusion-induced imbalance between the delivery of and requirements for oxygen and substrate leads to cellular dysfunction. The cellular injury created by the inadequate delivery of oxygen and substrates also induces the production and release of damage-associated molecular patterns (DAMPs or "danger signals") and inflammatory mediators that compromise perfusion through functional and structural changes within the microvasculature.one of the erliest changes seen in shock is the secretion of increased amounts of noradrenaline. ref:harrison&;s principles of internal medicine,ed 18,pg no 2221