Endocrine gland
The adrenal glands are located above the kidneys in humans and in front of the kidneys in other animals. The adrenal glands produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. It controls the behaviour during crisis and emotional situations. It stimulates the heart and its conducting tissues and metabolic processes.
Parathyroid chief cell
The parathyroid gland is part of the endocrine system. Most individuals display four parathyroid glands adjacent to the thyroid gland anterior in the neck. The chief cells are organized as dense cords surrounding the capillaries in the parathyroid. The thyroid gland and parathyroid gland are closely tied together in the calcium pathway. The thyroid gland secretes three hormones: T3, T4, and calcitonin. When the calcium level in the blood is too high, calcitonin is secreted, and the level is lowered. Calcitonin does this by depositing calcium in the bones. PTH works inversely from calcitonin. When the level of calcium in the blood is too low, PTH is released, and the level of calcium is raised. Calcium is released from the bone storage. This trigger also retains calcium from the urine, and alerts the intestines to absorb more calcium from ingested nutrients. Too much of either hormone can be an indicator of disease.