Higher tier only. The adrenal glands, which sit above the kidneys, produce the hormone adrenaline in times of fear or stress. Adrenaline increases the heart rate, so the heart beats faster. It boosts the delivery of oxygen and glucose to the brain and muscles. This prepares the body for flight or fight.
The thyroid gland produces thyroxine. Thyroxine stimulates the basal metabolic rate, which is the rate of the body's chemical reactions when at rest. It also plays an important role in growth and development.
Thyroxine levels are controlled by negative feedback. When the thyroxine level in the blood is too high, this reduces further release of thyroxine. When the level is too low, release of thyroxine increases. The level is therefore kept close to normal.