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The endocrine system

The endocrine system. Endocrine system. Is made up of glands that release hormones into the bloodstream to deliver messages throughout the body Messages travel slower than the nervous system, but their affect can last for days. Hormones.

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The endocrine system

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  1. The endocrine system

  2. Endocrine system • Is made up of glands that release hormonesinto the bloodstream to deliver messages throughout the body • Messages travel slower than the nervous system, but their affect can last for days

  3. Hormones • Are the chemicals that broadcast messages from the endocrine system • Are released from one part of the body and travel through the bloodstream to affect activities of cells in other parts of the body • Target cells are cells that have hormone receptors for a particular hormone • If there is no receptor for a certain hormone, then no affect will be seen

  4. Glands • Endocrine glands release their secretions into the blood stream • Exocrine glands, such as sweat, release their secretions directly onto their target location

  5. Control of endocrine system • Like most systems, the endocrine system is regulate by negative feedback mechanisms to maintain homeostasis

  6. Human endocrine glands • Pituitary gland • Hypothalamus gland • Thyroid gland • Parathyroid gland • Adrenal glands • Pancreas • Reproduction glands (gonads)

  7. Pituitary gland • Is a bean sized structure that dangles at the base of the skull • It is divided into two parts: the anterior and posterior portions • It secretes 9 hormones that directly regulate many body functions and controls the actions of several others endocrine glands

  8. Posterior pituitary hormones • Antidiuretic hormone (ADH)—stimulates he kidneys to reabsorb water • Oxytocin—stimulates contractions of uterus during childbirth; releases milk in nursing mothers

  9. Anterior Pituitary hormones • Follicle-Stimulating hormone (FSH)—stimulates production of mature eggs and sperm • Luteinizing hormone (LH)—stimulates ovaries and testes; prepare uterus for implantation of fertilized egg • Thyroid stimulating hormone (TSH)—stimulates the synthesis and release of thyroxine from the thyroid gland • Adreno-cortcotropic hormone (ACTH)—stimulates the release of some hormones from the adenal cortex

  10. Anterior pituitary hormones • Growth hormone (GH)—stimulates protein synthesis and growth in cells • Prolactin—stimulates milk production in nursing mothers • Melanocyte-stimulating hormone (MSH)—stimulates melanocytes of the skin, increasing their production of melanin

  11. Hypothalamus • Is the part of the brain above the pituitary gland • Controls secretions of the pituitary gland • Regulates when and how much hormones the pituitary gland secretes

  12. Thyroid gland • Is located at the base of the neck and wraps around the trachea • Has a major role in regulating the body’s metabolism • Releases thyroxine, the hormone which controls the metabolic activity of all cells in the body • Hyperthyroidism—causes nervousness, elevated body temperature, increased metabolic rate, weight loss, increased blood pressure • Hypothyriodism—may causes a goiter, and reverse symptoms of hyperthyroidism

  13. Parathyroid glands • Found on the back surface of the thyroid gland • Hormones from the parathyroid and thyroid act to maintain homeostasis of calcium levels in the blood • Parathyroid hormone (PTH)—increase calcium reabsorption in the kidneys and cause the digestive system to increase uptake of calcium as well

  14. Adrenal glands • Are pyramid like structures that sit on top of the kidneys • They release hormones that help the body prepare for and deal with stress • Releases many hormones (about 2 dozen) • Epinephrine and norepinephrineare released during times of stress to increase heart rate, blood pressure, blood flow to muscles, stimulate extra glucose into blood for instant energy, etc • We commonly call this adrenaline

  15. Pancreas • In additions to producing enzymes that break down food in the small intestine, the pancreas also makes hormones • Serves as both an endocrine and exocrine gland • Secretes both insulin and glucagon to help keep the level of glucose in the blood stable • Insulin—stimulates cells to remove sugars from the blood and store them as fat or glycogen • Glucagon—stimulates the liver to break down glycogen and to release sugars back into the blood • Diabetes results from improper functioning of these hormones

  16. Reproductive glands • The gonads serve 2 important functions • 1. the production of gametes • 2. the secretion of sex hormones

  17. Ovaries • The female gonads • Produce the female sex hormones of estrogen and progesterone • Estrogen—is responsible for development of eggs and the formation of the physical characteristics associated with the female body • Progesterone—prepares the uterus for the arrival of the developing embryo

  18. The testes • Male gonads • Produce testosterone • Is required for normal sperm production and the development of the physical characteristics of the male body

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