Mrs. Paparella Updated: April 23, 2012 Endocrine System Mrs. Paparella Updated: April 23, 2012

Endocrine System Glands produce and secrete chemical messengers called hormones that travel in the bloodstream.

The thyroid gets instructions from the pituitary to secrete hormones which determine the pace of chemical activity in the body (the more hormone in the bloodstream, the faster the chemical activity; the less hormone, the slower the activity)

Hyperthyroidism or thyrotoxicosis results from excess quantities of thyroid hormone in the body. This excess of hormones may be caused by tumors of the thyroid or rarely of the pituitary or ovaries, inflammation of the thyroid, or ingestion of excessive amounts of thyroid hormone or iodine.

Those with increased thyroid hormone levels experience heat intolerance, increased energy, difficulty sleeping, diarrhea and anxiety.

Graves Disease an autoimmune disorder of the thyroid which causes over-production of thyroid hormones. Hallmarks of the condition are bulging eyes (exophthalmos), heat intolerance, increased energy, difficulty sleeping, diarrhea and anxiety.

Parathyroid The parathyroid glands are located at the front and base of the neck around the thyroid gland and produce pararthyroid hormone. Parathyroid hormone regulates calcium, phosphorus, and magnesium balance within the blood and bone by maintaining a balance between the mineral levels in the blood and the bone.

Adrenal Glands

Adrenal Glands Triangular-shaped glands located on top of the kidneys. They produce hormones such as estrogen, progesterone, steroids, cortisol, and cortisone, and chemicals such as adrenalin (epinephrine), norepinephrine, and dopamine.

Pancreas: Insulin and Glucagon

Role of Insulin Islets of Langerhans contain beta cells and are located within the pancreas. Beta cells produce insulin which is needed to metabolize glucose within the body. When your blood glucose levels are higher(after eating a meal with carbohydrates) the pancreas will secrete insulin to help remove the glucose from the bloodstream and transport it into the cells of the body. Once the blood glucose level goes down, a negative feedback mechanism signals for insulin to stop being secreted.

Role of Glucagon Glucagon is a polypeptide made of 29 amino acids. It has the opposite effect of insulin: It raises the blood glucose levels. Glucagon stimulates breakdown of glycogen stored in the liver. When blood glucose levels are high, large amounts of glucose are taken up by the liver and stored in form of glycogen. Later, when blood glucose levels begin to fall, glucagon is secreted by the pancreas and acts on hepatocytes (liver cells) to activate the enzymes that depolymerize (break apart) glycogen and release glucose back into the blood stream so it can go where it is needed in the body’s cells for mitochondrial cellular respiration to make ATP. High blood levels of amino acids (after eating a protein –rich meal), cause glucagon to convert excess amino acids to glucose.

Ovaries The ovaries have two functions: they produce eggs (also called ova) and female hormones. The size of each ovary is about 1.5 inches long. Alternate name: female gonads The ovaries are the main source of female hormones (estrogen and progesterone). These hormones control the development of female body characteristics, such as the breasts, body shape, and body hair. The ovaries also regulate the menstrual cycle and pregnancy. . Polycystic Syndrome can result from imbalance of hormones; most functional cysts are harmless and go away w/o treatment. There are many different types of cysts.

Estrogen is a female sex hormone that stimulate the appearance of secondary female sex characteristics in girls at puberty. Estrogen controls the growth of the lining of the uterus during the first part of the menstrual cycle and cause breast development in pregnancy. Progesterone thickens the endometrial lining and when pregnancy occurs, supports the nourishing environment for the embryo to maintain the pregnancy. (placenta actually makes the progesterone during pregnancy.)

Testes Alternative Names: -Testicles -Gonads - male The testes are two egg-shaped male reproductive organs located in the scrotum. They produce sperm and the male hormone, testosterone. Alternative Names: -Testicles -Gonads - male

Functions of testosterone plays a role in determining the gender of developing fetuses. development of a deeper voice, muscle mass, facial hair growth and male genital development at puberty. contributes to an active sexual drive in both men and women. increases the metabolic functions in men, which contribute to faster healing and lower total body fat. Needed for sperm to mature and contributes to the overall quality of the sperm.

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