State the effect of norepinephrine on skeletal muscle contraction and heart muscle contraction.

Norephinephrine increases the ‘force of contraction’ of the skeletal muscle and the heart muscles.

Explanation:

This force of contraction is an important factor in the body’s fight –or-flight response by making it to retreat when exposed to a threat.  

Norephinehrine or noradrenaline is a catecholamine and the catechol group and the methyl group combines to form epinephrine which helps the body to act in a fight or flight response.  

It is for the same reason that norepinephrine is used during critical hypotensive conditions during heart attack, septic shock, neurogenic shock, etc.