The Endocrine System By: Tawny De Guzman

What is it? Endocrine system: organ system involved in the coordination of body activities; uses hormones as chemical signals secreted into the bloodstream

What does it do? Function: glands secrete hormones carried by the blood stream to target cells throughout the body Gland: a part of blood vessel and organ tissues that are specialized to secrete a substance

Homeostasis Homeostasis: the maintenance of balance of an organism’s internal environment The endocrine system: regulates metabolism, maintains salt, water, and nutrient levels in blood, controls responses to stress, and regulates growth, development, and reproduction

The Endocrine System’s Glands Hypothalamus, Pineal Gland, Pituitary Gland, Thyroid, Parathyroid, Thymus, Adrenal, Pancreas, Ovaries, Testes

Hormones Hormones: chemical messengers produced in one part of the body that control the activity of other parts Only certain cells (target cells) can respond to certain hormones; the hormone and receptor proteins bind together as a key fits in a lock

Types of Hormones Pheromones: chemical signals that influence the behavior of other individuals Peptide hormone: type of hormone that is a protein, a peptide, or derived from an amino acid Steroid hormone: hormones with the same complex of 4 carbon rings derived from cholesterol

Peptide Hormones in the Plasma Membrane 1.Peptide hormone binds to a receptor protein on the plasma membrane 2.This activates the change from ATP to cAMP (cyclic adenosine monophosphate) 3.cAMP (second messenger) activates enzyme cascade 4.Glycogen breaks down to glucose, which enters bloodstream

Steroid Hormones in the Plasma Membrane 1.Steroid hormone diffuses through plasma membrane 2.Hormone binds to receptor within nucleus 3.Hormone-receptor complex activates gene and synthesis of mRNA 4.mRNA moves to ribosomes, protein synthesis occurs

Pineal gland: releases melatonin Hypothalamus: controls pituitary hormones Pituitary gland: produces growth hormones, Prolactin, Adrenocorticotropic, thyroid- stimulating hormones, luteinizing hormones, and follicle- stimulating hormones Thyroid gland: secretes metabolism-controlling hormones Parathyroid glands: secrete PTH, which releases calcium into bloodstream

Adrenal glands: produce estrogen, progesterone, cortisol, & cortisone for blood-sugar control Pancreas: secrete insulin & glucagon to regulate blood glucose levels Testes: produce testosterone to maintain libido, muscle strength, & bone density Ovaries: secrete estrogen & progesterone to maintain the health of the female reproductive system

Negative Feedback Mechanisms Blood pressure falls sensory receptors signal the brain’s control center nerve impulses sent to restrict arterial walls blood pressure rises

Negative Feedback Mechanisms Blood glucose level rises pancreas releases insulin promotes glucose uptake by liver, muscles, and other cells

Hypothyroidism Lack of thyroid hormone, which controls metabolism About 10 million Americans have Hypothyroidism; 1/4000 newborns Some causes: autoimmune thyroiditis, surgical removal of thyroid, radioactive iodine therapy Symptoms: fatigue, weight gain, hair loss, coarse hair, cold intolerance, dry, rough, and pale skin, muscle achiness Treatment: daily dose of LT4 (levothyroxine)

Works Cited “Endocrine Glands and Types of Hormones.” Hormone.org. Endocrine Society Web. 28 May and-types-of-hormones “Hypothalamus.” Healthline. Healthline Media Web. 28 May Mader, Sylvia S. Biology. New York: McGraw-Hill, Print. Norman, James. “Hypothyroidism: Too Little Thyroid Hormone.” Endocrineweb. Vertical Health LLC, 11 April Web. 29 May too-little-thyroid-hormone

Works Cited (cont.) Orlander, Phillip R. “Hypothyroidism Treatment & Management.” Medscape. WebMD LLC. 19 February Web. 29 May Sargis, Robert M. “About the Endocrine System.” Endocrineweb. Vertical Health LLC, 18 February Web. 26 May system Vyas, Jatin M. “Adrenal Gland Hormone Secretion.” MedlinePlus. U.S. National Library of Medicine. 3 May Web. 29 May