Endocrine System

Endocrine System

The endocrine system provides the body with the hormones that are needed to sustain life and create life. Hypo and hyper secretion of the endocrine glands leads to physiological problems.

Physiology

Endocrine system is a control system of ductless glands that secrete hormones within specific organs. Hormones acts as “messengers” and are carried by the blood stream to different cells in the body, which interpret these messages and act on them. It provides an electrochemical connection from the hypothalamus of the brain to all the organs that control the body metabolism, growth and development, reproduction and also maintain homeostasis.

The endocrine system regulates its hormones through negative feedback. Increases in hormones activity decrease the production of that hormone

The endocrine system consists of these glands

•      Hypothalamus       

•      Pituitary gland

•      Pineal gland 

•      Thyroid

•      Parathyroid  

•      Adrenal glands

•      Pancreas       

•      Ovaries

•      Testes           

Hypothalamus

The hypothalamus lies within the cranium which regulates the homeostasis. The hypothalamus regulates the release or slow down and stop the release of hormones from other endocrine glands based on the blood levels of these hormones.

Pituitary Gland

Located at the base of the brain, is the master gland which controls the secretion of several other glands included in the endocrine system.

Pineal Gland

The pineal gland is a small endocrine gland that lies close to the hypothalamus, performs the coordination of circadian rhythm (sleep - wake cycle).

Thyroid Gland

The Thyroid gland shaped like angel wings on each side of the throat just above the trachea, are connected to each other with a thin connecting area called the Isthmus.

The Thyroid gland regulates the body’s metabolism, basal metabolic rate, cardiac system’s function, physical growth and sexual Parathyroid Glands (“para” means around and “thyroid” is thyroid gland).

The parathyroid glands are two pairs of glands found bilaterally on both sides of the neck just behind the Thyroid gland. The body has four parathyroid glands which is unique when compared to the other glands of the endocrine system. The role of the glands is to control the circulating amount of two electrolytes, calcium and phosphorous with the secretion of parathyroid hormone.

Adrenal Glands

The adrenal glands, which are in the abdominal area, are located bilaterally just above each kidney and the diaphragm. The adrenal glands consist of two layers, the cortex (outer layer) and the medulla (inner core).

The cortex secretes:

·              Androgen - male hormone

·              Aldosterone - controls blood pressure and fluid balance

·              Cortisol - regulates and coordinates metabolism

The medulla secretes stress reaction hormones such as:

•      Adrenaline   

•      Noradrenaline

•      Catecholamine

The Pancreas

The pancreas is located behind the stomach. The islets of Langerhans secrete glucagon, insulin, pancreatic polypeptide and somatostatin. The pancreas produces and releases digestive enzymes and juices that break down foods as they enter the small intestine.

Testes and Ovaries

Ovaries and Testes are the endocrine glands and gonads, which is called as a sex and reproduction glandular structure.

The ovaries produce progesterone, estrogen, inhibin and androstenedione. Progesterone regulates menstrual cycle and the preparation of the uterus for the implantation of the egg. Estrogen regulates the development of breasts. Inhibin inhibits Follicle Stimulating Hormone (FSH) in females and in males it inhibits the development of sperm and androstenedione (androgen that is weaker than testosterone).

The testes produce androgens, testosterone and sperms.

Diseases related to endocrine system

·              Diabetes insipidus

·              Acromegaly

·              Gigantism

·              Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)

·              Hyperthyroidism

·              Hypothyroidism

·              Cushing’s syndrome

·               Addison’s disease