Endocrine System By Bryce Tappan

Function of the Endocrine System The function of the endocrine system is to regulate the production and use of hormones within the body. Glands make hormones that help to control metabolism, sexual development and bodily growth.

Homeostasis A part of the endocrine system, the hypothalamus is acts as a mediator in the brain between the nervous and endocrine systems, and one of its functions is to maintain homeostasis. Some aspects of the human body that must be maintained are body temperature, protein production, energy consumption etc.

Negative Feedback Mechanisms Just as in the reproductive system, hormones are controlled by a system of negative feedback mechanisms. Levels of certain hormones in the body move in cycles.

Negative Feedback Mechanism Example An example of negative feedback and hormones is the regulation of the thyroid gland, which controls energy consumption, protein production and calcium in the blood. The process has several steps: The hypothalamus detects a deficiency in thyroid-produced hormones Hypothalamin is released and it stimulates anterior pituitary cells responsible for secretion. The anterior pituitary releases more hormones that stimulate the thyroid gland to make more hormones If too many thyroid hormones are produced, the production of excess thyroid hormones inhibits the continued production of more of those same hormones.

Hormones & Glands: The Hypothalamus The hypothalamus is a connecting point between the nervous system and the endocrine system and is crucial for maintaining homeostasis. Blood vessels connect the hypothalamus and the pituitary gland, allowing the hypothalamus to control the secretion of hormones from the pituitary gland.

Hormones & Glands: The Pituitary Gland Hypothalamic hormones control hormone secretion in the pituitary gland, which then directs other major organs and glands in the body. The pituitary gland is important for the growth and production of nine different hormones including: human growth hormones, thyroid stimulating hormones, Corticotropin-Releasing Hormones, and others. The pituitary gland is a major regulator of the endocrine system and homeostasis.

Hormones & Glands: Adrenal Glands The adrenal glands are situated above the kidneys, and they release hormones in response to stress. The adrenal glands also regulate kidney function by secreting a hormone called aldosterone. Aldosterone is important in controling the solute concentration in blood plasma.

Hormones & Glands: Pineal Gland Located in the brain, the pineal gland secretes melatonin which regulates the pituitary gland and is thought to be the cause of the “biological clock.”

Hormones & Glands: The Thyroid Gland The thyroid gland in the neck is responsible for secreting hormones that regulate the amount of energy the body uses, as well as calcium intake to the bones.

Hormones & Glands: The Thymus During infancy, the thymus controls the growth of lymphoid tissues and immune system responses to pathogens. They are an important gland for the immune system in that they are responsible for releasing hormones that activate T-cells.

Hormones & Glands: The Pancreas The pancreas acts a gland that excretes enzymes into the small intestine. It also produces insulin, which converts glucose into glycogen.

Hormones & Glands: The Ovaries Hormones such as oestrogen and progesterone are released within the ovaries, and they control the build up and break down of the tissues within the uterus. They also control the development of reproductive organs.

Hormones & Glands: The Testes Within the testes, testosterone is responsible for developing the male reproductive system and for causing physical changes to the body during puberty.

Disorders: Diabetes I A)Diabetes mellitus type 1 is caused by the destruction of insulin-producing cells of the pancreas. B)The lack of insulin leads to an increase in the levels of glucose in the blood and the urine. The symptoms include frequent urination, hunger and weight loss, and it can be fatal. C)Type I Diabetes is not that common, ranging from people out of 100,000 D)It can be treated by the addition of insulin to the body along with proper dieting.

Disorders: Diabetes II A)Type II Diabetes is caused by a metabolic deficiency of insulin, unlike type I which is caused by the destruction of insulin producing cells in the pancreas. B)The symptoms are the same as those of type I, with the exception of obesity. C)Type II Diabetes comprises 90% of the total Diabetes cases D)Treatment is similar to that of type I, along with an exercise regimen.

Disorders: Anaplastic Thyroid Cancer A) Anaplastic thyroid cancer may be caused by exposure to radiation, and is characterized by anaplastic tumors on the thyroid gland. B) A noticeable growing mass in the neck is a good indicator of thyroid cancer; tumors develop and may spread quickly from the thyroid gland. C) Anaplastic thyroid cancer is the least common type of thyroid cancer. D) Thyroid cancer is very difficult to cure, only a small fraction of patients may have successful surgeries to remove the tumor before it spreads. Radiation therapy may also combat thyroid cancer. cancer-anaplastic-cancer