What does adrenaline do?


Quick Answer

Adrenaline, also known as epinephrine, primarily boosts the heart rate, raises blood pressure, expands the lung air passages and dilates the pupil in the eye. It acts on various kinds of cells and generates numerous actions to prepare the body to respond vigorously during stressful times.

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Full Answer

When a person feels fear or danger, the stressor triggers the hypothalamus, which is the part of the brain that stabilizes the body’s stress and relaxation levels, to transmit a chemical signal to the adrenal glands. These glands activate the sympathetic system, which causes the body to become energized. The adrenal glands secrete adrenaline and noradrenaline, which are the hormones that enable the body to face danger.

Adrenaline sends blood to the muscles to change the body’s metabolism and to increase glucose levels to support the brain. It also slows digestion and enables muscles to contract. Moreover, adrenaline allows the body to convert glycogen into glucose to provide more energy to the muscles. These physical changes help a person become more prepared to handle dangerous situations. They make an individual faster, stronger and more capable of processing information.

When the body experiences acute stress, the pituitary gland also releases adrenocorticotropic hormone, which prompts the cortex of the adrenal glands to generate the steroid hormone called cortisol. During long-term stressful events, cortisol plays a key role in controlling the body’s metabolism.

Learn more about Glands & Hormones

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