You are watching a horror movie. the music changes to the familiar tune you recognize as a prelude to danger. you tense up, your heart rate increases, your breathing becomes shallow, and your mouth is dry. which branch of the nervous system has been activated?

Sympathetic nervous system is activated in this situation.

This branch of nervous system is activated when any individual encounters stressful or dangerous situation.This is responsible for 'fight or flight' response.

It takes place by activating adrenal gland which releases specific hormones adrenaline and nor adrenaline also called as catecholamines . These hormones are responsible for the appropriate physiological response to the situation.

Biceps

Abductor

Internal

Rectus

Explanation:

Biceps mean that the muscle attaches to two origins. The "bi" part means "two", so tri-ceps will have 3 origins.  

Abductor tells what action the muscle does. Abduction is the movement that pulls away from the body. Its the opposite of induction.

Internal give location of the muscle. Internal mean it is in a deeper layer while external muscle will be at a higher layer.

Rectus mean straight. It means the muscle fiber direction is straight.