1 The phenotype may change constantly throughout the life of an individual because of environmental changes and the physiological and morphological changes associated with aging.
What is parathyroid hormone? Parathyroid hormone is secreted from the four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low.It does this through its actions on the kidneys, bones and intestine:hat is parathyroid hormone? Parathyroid hormone is secreted from the four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low.
In this way, it initiates the menstrual cycle. The pituitary gland, also known as the hypophysis, is a small gland connected to the hypothalamus by a stalk (called the infundibulum). The pituitary has 2 major lobes: the posterior and anterior.1  The posterior lobe is nerve tissue, and is really a downgrowth of the hypothalamus. Since it is a part of the brain, and made of nervous tissue, it has direct nervous influence. 2  It activates, controls and integrates the autonomic nervous system, and. 3  since it also acts as a gland, it's endocrine activity produces and secretes certain hormones and releasing factors.