steady rate throughout life, while others are secreted at an appropriate time in life. For example, the growth hormone is released steadily through childhood, with some spurt during adolescence, but gonadotropic hormones are secreted at the age of puberty, which stimulates the secretion of appropriate sex hormones among boys and girls. As a result, primary and secondary sexual changes take place. Thyroid Gland This gland is located in the neck.
It produces thyroxin that influences the body’s metabolic rate. Optimum amount of thyroxin is secreted and regulated by an anterior pituitary hormone, the Thyroid Stimulating Hormone. (TSH). The steady secretion of this hormone maintains the production of energy, consumption of oxygen and elimination of wastes in body cells.
On the other hand, underproduction of thyroxin leads to physical and psychological lethargy. If thyroid gland is removed in young animals, their growth is stunted and they fail to develop sexually. Adrenal Gland This gland is located above each kidney. It has two parts, adrenal cortex and adrenal medulla , each secreting different hormones.
The secretion of adrenal cortex is controlled and regulated by Adrenocorticotrophic Hormone (ACTH) secreted by anterior pituitary gland. When the secretion of adrenal cortex goes down, anterior pituitary gets the message and increases the secretion of ACTH, which stimulates the adrenal cortex to secrete more hormones. The adrenal cortex secretes a group of hormones, called corticoids , which are utilised by the body for a number of physiological purposes, e.g., regulation of minerals in the body, particularly sodium, potassium, and chlorides. Any disturbance in its function seriously affects the functions of the nervous system.
Pituitary Gland This gland is situated within the cranium just below the hypothalamus. The pituitary gland is divided into anterior pituitary and posterior pituitary. The anterior pituitary is directly connected with hypothalamus, which regulates its hor monal secretions. The pituitary gland secretes the growth hormone and many other hormones, which direct and regulate the secretions of many other endocrine glands found in our body.
This is why the pituitary gland is known as the “master gland”. Fig. . : Major Endocrine Glands Thyroid Pancreas Adrenal