The night is late and house is dark. As you make your way to the light switch in the dark room, something warm brushes against your leg. You let out a shriek and your breath is held up. Not until you realize that it is the cat do you breathe a sign of relief. Now your pounding heart begins to slow down and you begin to feel calmer. What causes these changes?

Source

Hormones: Such changes are set in motion by the glands of endocrine system and the nerves of the nervous system. In the endocrine system, glands produce chemical messengers called hormones that help regulate certain body activies. Together, the nervous system and endocrines system function to keep all parts of the body running smoothly.

The rush of fear in a dark room is an example of how nervous system and endocrine system work together?. When you brush against an unknown object in the dark, your senses report this information to your brain. Because your brain interprets the information as a threat, it quickly sends impulses through selected nerves. These nerves then trigger certain glands of the endocrine system. The selected glands then produce chemicals called hormones. Hormones are chemical messengers that travel through the blood. From the above example, you have known those glands are effectors. After receiving information from the brain, gland secretes hormones.

Endocrine glands: Endocrine glands are ductless. They use the circulatory system a deliver hormones. So endocrine glands do not need to be near the organs they control. No matter where the hormones enter the blood stream, they always find their way through the vessels to their intended target-area, because body tissues have the ability to recognize’ the hormones that are made for them. Now you shall study the important glands and their functioning.

Hypothalamus: It is a tiny gland at the base of the brain. It produces some very special hormones which help turn on and off the activities of other endocrine glands all over the body.

Pituitary: It is a small pea-shaped gland located at the base of the skull just below the hypothalamus.
Pituitary gland produces hormones which help control blood pressure and water balance in the body. It produces the all important human growth hormone or HGH. It produces yet another hormone or TTH. It stimulates the thyroid gland for the secretion of thyroxin.

Thyroid: The thyroid is located at the base of the neck slightly below the larynx or voice box. It secretes two hormones- calcitonin and thyroxin. The first one controls the level of minerals, calcium and phosphorus in the body. The second hormone controls metabolism.

Adrenals: In moments of sudden stress, the two adrenal glands, which are located atop each kidney, release a hormone called adrenalin. This hormone causes the heart to beat faster and steps up the rate of other body processes.

Pancreas: below the stomach is the pancreas gland which contains special cells that release hormones –insulin and glucagons. Insulin reduces the level of sugar in the blood stream by helping body cells absorb sugar and use it for energy. The second hormone glucagons, causes an effect directly opposite to that of insulin. It causes a rise in the level of sugar in the blood.

Testes: These are two oval-shaped structures found inside an external sac. The testes produce a hormone called testosterone which is responsible for the growth of facial and body hair, broadening of the shoulders, and deepening the voice in males.

Ovaries: Two structures, called ovaries, are located at about hip level, one on each side of a female’s body. Like the testes, ovaries produce hormones one of these hormones called estrogen, triggers the broadening of the hips in females. It also starts the maturation of egg cells in the ovaries.