Several glands comprise the endocrine system. The endocrine systems is integrated into the nervous system by the hypothalamus.  It receives signals from the brain and the peripheral nerves, then initiates the endocrine system. The hypothalamus cells are nuerosecretory cells. The cells receive a nerve impulse and trigger the release of hormones in the blood stream.

The thalamus partially encloses the third cranial ventricle. It acts as a sensory hub for the cranial nervous system, and recognizes pleasant and unpleasant sensations. It consists of two parts the Hypothalamus and the Epithalamus.  The Hypothalamus acts as an important automatic nervous system hub.  It regulates the body’s temperature, metabolism, and water ratio. The Epithalamus forms a roof over the third cranial ventricle, and is composed of the pineal body as well as the choroid plexus.

The pituitary is sometimes referred to as the master gland, it consists of two lobes. The posterior lobe, called the neurhypophysis, which stores hormones manufactured by the hypothalamus and secretes them on command. And the anterior lobe, called the adenohypophysis, which is able to produce it’s own hormones.

The thyroid gland is located on the front surface of the trachea and is controlled by the hypothalamus and the pituitary. It has two lobes, and it produces two hormones: Triiodothyronine (T3) and Thyroxine (T4).  Both T3 and T4 have the same effect on the target cell, but T3 is usually most active. The thyroid also regulates metabolism.

The pancreas secretes insulin, a hormone that regulates the glucose in-take of the cells. A deficiency in this hormone results in diabetes mellitus.  Which is simply lack of sufficient blood sugar.  Insulin regulates the blood sugar levels by stimulating cells to take in glucose. It also stimulates the synthesis of protein and fat storage.

The adrenal medulla is the gland behind the basic human fight-or-flight reaction. It secretes two hormones: epinephrine and norepinephrine. (Epinephrine is also known as adrenaline.) Epinephrine secretion is triggered by stress, both positive and negative stress. It increases the rate and the stroke volume of the heart.  Norepinephrine causes the rate of metabolic processes to slow down allowing for sleep, and relaxation.

Androgens are primarily produces by the testis, and stimulate the maintenance and development of the male reproductive system.  Testosterone is the primary hormone in this group

Estrogens are the female equivalent of Androgens. They maintain the female reproductive system and trigger the development of female second sex characteristics. Progestins maintain and prepare the uterus for growth and development of an embryo.