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.
Hormones are like 'impulses' from the glands. In order to stimulate a particular response, more than one hormone may need to be released. The pituitary gland, found at the base of the brain, influences the activity of the other endocrine glands.It is controlled by the information it receives from the brain.ne remarkable feature is the speed of the response which is virtually instantaneous. The central nervous system is composed of specialised cells called nerve cells or neurones. These cells are bound together by connective tissue to form nerve fibres.