The Endocrine System


The endocrine system is the body’s slow chemical communication system. It consists of a set of glands that secrete hormones directly into the bloodstream. Hormones are chemical messengers mostly manufactured by the endocrine system. Hormones are produced in one tissue and affect another.

The hypothalamus sits below the thalamus and directs maintenance activities such as appetite, thirst and body temperature. Furthermore, it helps govern the endocrine system via the pituitary gland.

The thyroid gland is located in the front of the neck, below the larynx. The thyroid plays a crucial role in regulating our metabolism and calcium levels. T4 and T3 hormones released by the thyroid stimulate our tissue to produce protein and increase use oxygen to encourage cellular work. The chemical activity that is known as cellular work or activity is known as metabolism. The hormone calcitonin also released by the thyroid works along side the parathyroid hormone to regulate our calcium levels. The thyroid gland is controlled by hormones released by the pituitary gland.

The adrenal glands sit above the kidneys. They secrete epinephrine (adrenaline) and norepinephrine (non-adrenaline). They are vital to the autonomic nervous system.

The pancreas regulates the level of sugar in our blood. The part of the pancreas involved in the endocrine system is made up tiny cell clusters called islets of Langerhansα cells secrete glucagon which increases glucose in the blood, β cells secrete insulin which decreases glucose in blood, delta cells secrete somatostatin which regulates α and β cells. People that suffer from diabetes do not produce enough insulin which causes dangerously high blood sugar levels that must be regulated by an insulin shot or pump.

The ovaries and testes regulate sex hormones, female and male respectively. The ovaries, at the opening of the fallopian tubes, produce estrogen and progesterone, which play a crucial role in female development and reproduction. The testes, inside the male scrotum, produce testosterone, which affects male development and sperm production.

The pineal gland produces several important hormones including melatonin. Melatonin influences sexual development and the sleep-wake cycles.

The thymus gland is not really part of the endocrine system despite being a gland. It’s most important function is the production of T-lymphocytes, a type of white blood cells. This makes the thymus gland a quintessential part of the immune system.


Bailey, Regina. “Pineal Gland.” Biology. N.p., n.d. Web. 10 Sept. 2012. <;.

“Endocrinology Health Guide.” University of Maryland Medical Center. N.p., n.d. Web. 10 Sept. 2012. <;.

Myers, David G. Psychology . 6. Worth Publishers, 2001. Print.Myers, David G. Psychology . 6. Worth Publishers,2001. Print.

“Pancreas: Function.” Pancreas: Function. N.p., n.d. Web. 10 Sept. 2012. <;.