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 hypothalamus also activates the adrenal medulla. The adrenal medulla is part of the autonomic nervous system (ANS). The ANS is the part of the peripheral nervous system that acts as a control system, maintaining homeostasis in the body. These activities are generally performed without conscious control.