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.
One special group of hormones is the tropic hormones that stimulate the hormone production of other endocrine glands. For example, thyroid-stimulating hormone (TSH) causes growth and increased activity of another endocrine gland, the thyroid, which increases output of thyroid hormones. hormone (from Greek á½ÏÎ¼Î®, impetus) is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour.
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.