1 / 17

The Endocrine System

The Endocrine System. What is the Endocrine System. Group of ductless glands that secrete substances (hormones) directly into the bloodstream Do not secrete into an organ but directly into the bloodstream These hormones have a direct effect on a target organ/tissue . Hormones.

henrik
Download Presentation

The Endocrine System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Endocrine System

  2. What is the Endocrine System • Group of ductless glands that secrete substances (hormones) directly into the bloodstream • Do not secrete into an organ but directly into the bloodstream • These hormones have a direct effect on a target organ/tissue

  3. Hormones • chemical substances produced & secreted by the endocrine glands • Purpose • Stimulate exocrine glands • Stimulate other endocrine glands • Regulate growth & development • Regulate metabolism • Maintain fluid & electrolyte balance • pH of body fluids • Control reproduction processes

  4. How do they work? • Negative Feedback – acts on a stimuli & then feedback to the gland; gland then decreases the secretion • Releasing hormones – tell other glands to secrete hormones • Antagonistic – effect blood chemistry

  5. Different glands • Pituitary • Thymus • Thyroid • Parathyroid • Pancreas • Adrenals • Ovaries • Testes

  6. Pituitary • “Master Gland” • Works closely with the hypothalamus • Hangs from the hypothalamus & enclosed in the sphenoid bone • Has an anterior & posterior secreting area

  7. Anterior Posterior • Growth Hormone (GH) • Thyroid stimulating hormones (TSH) • Adrenocorticotropic hormone (ACTH) • Prolactin • Follicle-stimulating hormone (FSH) • Luteinizing hormone • Antidiuretic hormone (ADH) • oxytocin

  8. Antidiuretic Hormone (ADH) • Increases the reabsorption of H20 from the kidneys • This decreases the amount of urine produced • Decreases sweating • Increases blood volume; Increases BP • Hypothalamus “monitors” the saltiness of the blood • Hypothalamus tells the pituitary to release ADH • Alcohol inhibits the secretion of ADH

  9. Oxytocin • Stimulates the uterus to contract • Releases milk • Dilation of the cervix triggers the pituitary to secrete • Positive feedback; delivery of baby & placenta will decrease the release • Placenta secretes large amounts of oxytocin (Trigger labor?) • “let down” effect from nipples • ADH & oxytocin promote mother-baby bonding

  10. Growth Hormone (GH) • Also known as somatotropin • Increases amino acids into cells • Increases protein synthesis • Increases mitosis in cells • Bones • muscles • As adults, replaces tissue that has aged • Growth Hormone Releasing Hormone (GHRH) is produced by the hypothalamus when hypoglycemia & exercise to INCREASE blood amino acids

  11. Thyroid Stimulating Hormone (TSH) • Acts on the thyroid • Causes the thyroid to produce T3 & T4 • Hypothalamus tells the pituitary to produce

  12. Adrenocorticotropic (ACTH) • Acts on the adrenal glands • Causes the release of cortisol & other adrenal hormones • Activates in stressful state • Injury • Exercise • Disease • Hypoglycemia (hunger)

  13. Prolactin • Produced for lactation • Maintains milk production in women • Prolactin releasing hormone (PRH) & Prolactin inhibiting hormone (PIH) from hypothalamus

  14. Follicle Stimulating Hormone (FSH) • Development (maturity) of ova (eggs) every 28 days • Stimulates the ovaries to secrete estrogen • Initiates sperm production in testes • Gonadotropin-releasing hormone (GnRH) by hypothalumus • Inhibin – by the ovaries or testes to decrease secretion of GnRH

  15. Luteinizing Hormone • Gonadotropic hormone • Women – responsible for ovulation • Follicle (ovum) develops into a corpus luteum (secretes progesterone) • Men – causes the cells in the testes to secrete testosterone

  16. Thyroid Gland • Located front of the trachea • Divided into Left Lobe; Right Lobe; & Isthmus(Middle) • Produce T3 & T4 • Needs iodine for hormones (T3 – 3 molecules of iodine) (T4 – 4 molecules of iodine) • Calcitonin

  17. T3 & T4 • Regulate energy production • Protein synthesis • Increases cellular respiration • Increases energy & heat production • Increases protein synthesis • Needed for normal mental development & physical growth • Maturation of sex organs • Controls day-to-day metabolic rate • Can live without but needed for optimal physical & mental ability & growth

More Related