Definify.com

Webster 1913 Edition

Noun.

pl.

Organs that are necessary for life; more especially, the heart, lungs, and brain.

Fig.: The part essential to the life or health of anything;

as, the

vitals

of a state

“The vitals of the public body.”

Glanvill.

Noun.

plu.

Parts of animal bodies essential to life, such as the viscera.

The part essential to life, or to a sound state. Corruption of manners preys upon the vitals of a state.

vitals pl ‎(plural only)

(plural only) Those organs of the body that are essential for life.
(plural only, figuratively) Those parts of a system without which it cannot function.
(medicine, plural only) Vital signs.

1827 Ann Hasseltine Judson - An account of the American Baptist mission to the Burman empire
they were ripped open from the lowest to the highest extremity of the stomach, and their vitals and part of their bowels were hanging out
2003 David R Woodward - Trial by Friendship: Anglo-American Relations, 1917-1918
This final victory can only be had by reaching the vitals of Germany and by destroying her armed forces.
1991 Suzy Szasz - Living With It: Why You Don't Have to Be Healthy to Be Happy
At least once an hour a nurse came into the room, either to check on me or my roommate, or to take vitals