Physiological responses to emotion..

Anger - Heartrate increase, Rush of hormones 'Adrenaline' generates energy strong enough for vigorous action.

Fear - Blood goes to larges skeletal muscles eg. Legs , making it easier to flee. Face goes white as blood leaves. At the same time, the body freezes, if only for a moment, perhaps allowing time to guage whether hiding might be a better reaction. 'fight-or-flight'

Happiness - A brain centre inhibits negative feelins and fosters an increase of available energy. Quietening of those centres that generat worrisome thought.

Love - Tender feelings and sexual satisfaction entail 'parasympathetic' arousal - the opposite physiological state of 'fight-or-flight' shared by fear and anger. The parasympathetic pattern, (dubbed the 'relaxation response') is a set of reactions that generates a general state of calm and contentment.

Surprise - Lifting of the eyebrows allows the taking in of a larger visual sweep & permits more light to strike the retina. Offering more visual info about the unexpected event, making it easier to figure out what's going on and concoct the best plan of action.

Disgust - Around the world expression of disgust looks the same = Something is offensive in taste or smell, or metahorically so. Upper lip curled as nose wrinkles slightly, suggests an attempt to close the nostrils against a noxious odor or to spit out poisonous food.

Reference, 'Emotional Intelligence' by Daniel Goleman