The Endocrine System

(pronounced EN’ – do- krin)

The Endocrine System

• The endocrine system consists of glands• These glands secrete substances called

hormones in the bloodstream• Hormones stimulate growth and affect mood• Some of the more significant glands include

the pituitary gland, the thyroid gland, the adrenal glands, and the testes and the ovaries

The Pituitary Gland

• The pituitary gland is a very small, but a very important gland

• It is about the size of a pea, located under the hypothalamus

• It produces growth hormone, which controls how much you grow, oxytocin, which stimulates labor in pregnant women, and prolactin, which stimulates milk production for new mothers

Robert Wadlow

Robert Wadlow had a non-cancerous tumor near his pituitary gland, and human growth hormone was therefore produced in overabundanceHere, he is standing next to his dad, who was roughly my height)Robert Wadlow was still growing at the age of 22, when an infection in his leg was not treated correctly, and he died.He was 8’11 ½” tall when he died, still growing about 2 inches per year

The Thyroid Gland

• The thyroid gland is located in the neck, near the throat, and produces thyroxin

• Thyroxin affects the body’s metabolism, how fast the body converts food into energy

• Too little production of thyroxin can lead to a chronic problem of being overweight

• Too much production can lead to excitability, inability to sleep, and weight loss

The Thymus

• The thymus is located near the heart• It helps with the immune system by creating

“T-cells” that attack infections• These T-cells can be defeated by HIV/ AIDS, so

that infections can run rampant in the body with nothing to fight against them

The Pancreas

• The pancreas is located near the stomach, and helps with digestion

• The pancreas produces insulin, which helps regulate the amount of sugar in the bloodstream

• An imbalance of insulin leads to diabetes• The pancreas also produces other important

digestive hormones

The Adrenal Glands

• The adrenal glands are located above the kidneys (ad --Latin for at; renes – Latin for kidneys)

• Outer layer, or cortex, of the adrenal glands secrete cortical steroids

• Cortical steroids increase resistance to stress and promote muscle development

• Adrenal glands also produce adrenaline and noradrenalin, which arouses the body and intensifies fear and anxiety

Testes and Ovaries

• Testes and ovaries produce testosterone, estrogen, and progesterone

• While testes primary produce testosterone, they do produce a small amount of estrogen and progesterone as well

• Ovaries produce a small amount of testosterone along with more major production of estrogen and progesterone

Testosterone• Testosterone is the male sex hormone, although

females do have some in small amounts• Eight weeks after fertilization, if testosterone is

secreted when a baby is developing, he will become male. If not, she will become female

• Testosterone aids in primary and secondary sex characteristics for males during adolescence: i.e. beard growth, muscle development, and ability to reproduce

• Testosterone is a steroid, and is sometimes abused by athletes who are trying to gain an advantage. This can cause cancer or otherwise be detrimental to their health.

Estrogen and Progesterone

• Estrogen and progesterone are female sex hormones, produced by ovaries, although low levels are found in males, produced by testes

• These hormones foster development of primary and secondary sex characteristics, such as breast development and menstrual cycles

• Premenstrual syndrome (PMS) can develop due to changes of estrogen before ovulating. PMS can lead to irritability, depression, or fatigue

Assessment

• Answer the two questions on page 69. Write at least a paragraph answer for each (offer as much detail as you can).