In this case, the damper is normally opened by the force of the spring but can be closed by the force of the motor. Removal of electrical power re-opens the damper. This style of damper is advantageous because it is fail safe; if the control to the damper fails, the damper opens and allows air to flow.
The adrenal glands, located on the top of each kidney, are responsible for releasing different classes of hormones. The outer part of the gland, called the adrenal cortex, produces the hormones cortisol (pronounced KAWR-tuh-sohl) and aldosterone (pronounced al-DOS-tuh-rohn). The inner part of the gland, called the adrenal medulla (pronounced muh-DUHL-uh), produces the hormones adrenaline and noradrenaline.
The inner part of the adrenal gland. The adrenal medulla produces the hormones epinephrine (adrenaline), which stimulates the heart, tightens blood vessels, and relaxes some smooth muscles; and norepinephrine, which has similar effects.drenal medulla, the inner portion of the adrenal gland. Its cells secrete the catecholamines epinephrine and norepinephrine when stimulated by the sympathetic division of the autonomic nervous system.