Overview of Endocrine System

The endocrine system functions in a similar manner, like the nervous system. In nervous system, electrical messages are sent to coordinate the body organs; whereas, in case of endocrine system, chemicals, called hormones are used to communicate between different parts of the body. Hormones are messenger chemicals that are synthesized and secreted by the endocrine gland. They play a major role in the body, right from growth, development, body metabolism to reproduction. Let's take a look at the overview of the endocrine system, giving emphasis on the endocrine glands and their hormones secretion.

Endocrine Glands

The term 'endocrine' itself refers that as the body receives certain stimuli, the hormones are poured into the bloodstream. In contrast to digestive glands that have ducts, endocrine glands are ductless and release the products directly in the bloodstream. The endocrine glands include the following:

Hypothalamus: Hypothalamus consists of very small clusters of cells that are located just above the pituitary gland. It controls the function of the pituitary gland, by producing hormones that induce the pituitary gland, which in turn affects hormone secretion of the other glands. Hormones secreted by hypothalamus include growth hormone-releasing hormone (GHRH), somatostatin and dopamine.

Pituitary Gland: The pituitary gland is located behind the nose bridge and at the center of the skull. It is divided into two parts - the anterior lobe and the posterior lobe. The pituitary gland is responsible for producing hormones that affect growth, body metabolism, sexual development and reproduction. Hormones released by anterior lobe are thyroid stimulating hormone (TSH), follicle stimulating hormone (FSH), luteinizing hormone, (LH) prolactin (PRL), growth hormone (GH), adrenocorticotropic hormone (ACTH). The posterior lobe of the pituitary gland produces oxytocin and vasopressin.

Thyroid Gland: Thyroid gland is located in front of the windpipe and consists of two small lobes. The thyroid gland produces two important hormones - thyroxine and triiodothyronine, which regulates the metabolic rate of all the cells of the body.

Parathyroid Gland: Behind the thyroid gland, there are four small pea sized bodies called the parathyroid gland. It secretes the parathyroid hormone, which controls and regulates calcium metabolism in the body.

Pancreas: Pancreas is located in the abdominal region, behind the stomach. Pancreas secretes digestive enzymes and the hormones - insulin and glucagon that play an important role in the blood glucose metabolism.

Adrenal Glands: Adrenal glands are small structures, located on the upper side of the kidney. There are two parts in the adrenal glands - the adrenal cortex and the adrenal medulla. Adrenal cortex produces steroid hormones and also controls the salt and carbohydrate metabolism; whereas, adrenal medulla secretes epinephine (for calming down) and norepinephrine (for excitement).

Gonads (testes and ovaries): Gonads produces sex hormones (steroids), which are essential for development and functioning of the reproductive organs in both males and females.

In the endocrine system, the hormones are regulated and coordinated in such a way that the body is balanced and maintained, according to the change in the environment. Any disorder in the endocrine system can cause certain health problems such as thyroid problems and adrenal problems. Apart from the organs of the endocrine system, there are several other organs that produce hormones, for e.g. the epithelial cells in the stomach lining and small intestine. These hormone producing organs are sometimes referred to as diffuse endocrine system.