What happens to us physiologically when we are angry?

The external expression of anger can be found in facial expressions, body language, physiological responses, and at times in public acts of aggression. The facial expression and body language are as follows.
The facial and skeletal musculatures are strongly affected by anger. The face becomes flushed, and the brow muscles move inward and downward, fixing a hard stare on the target. The nostrils flare, and the jaw tends toward clenching. This is an innate pattern of facial expression that can be observed in toddlers. Tension in the skeletal musculature, including rising of the arms and adopting a squared-off stance, are preparatory actions for attack and defence. The muscle tension provides a sense of strength and self-assurance. An impulse to strike out accompanies this subjective feeling of potency.
Physiological responses to anger include an increase in the heart rate, preparing the person to move, and increase of the blood flow to the hands, preparing them to strike. Perspiration increases (particularly when the anger is intense). This is a direct effect of excessive adrenalin in our system. Our physical strength increases although spiritual strength decreases.
Our intellect or power to reason disappears, and things we would not justify in a normal state become acceptable