Adrenaline hormone is secreted in large amounts when a person is frightened, or mentally disturbed and prepares the body for emergency situations. When it reaches the heart, it beats faster to supply more oxygen to our muscles. Contractions of diaphragm and the rib muscles leads to the increase in breathing rate. It also raises the blood pressure, and allows more glucose to enter into the blood. Slight precipitation also occurs on the temple and in palms.All these collectively shows the body is prepared for emergency situations.