Hormonal Regula8on of Homeostasis

Transcription

1 Hormonal Regula8on of Homeostasis Chapter 13 (MH) 15 (N) MH: 436 N: 470 MH: 436 N: 470 Glands and hormones Endocrine glands secrete chemical messengers called hormones Hormones are delivered to target cells via the bloodstream Hormones keeps the body s homeosta8c balance by adjus8ng the internal environment according to the nervous system s interpreta8on of the external environment MH: 437 N: 471 1

2 IMAGE SOURCE: Nelson Biology MH: 438 N: 471 Research and evidence Connected circulatory systems of two rats revealed the presence of tes8cular hormones in the castrated rat WITH a pituitary gland, and pituitary hormones in the tes8cularly intact rat were present even auer removal of its pituitary gland. MH: 438 N: 471 Nega8ve feedback MH: 441 N: 474 2

3 MH: 441 N: 482 Nega8ve feedback Generally, tropic hormones from the hypothalamus release tropic hormones from the anterior pituitary Tropic hormones are hormones that target the cells of other endocrine glands When receptors of the tropic glands hold a sufficient concentra8on of the target hormone, the tropic glands stop produc8on of the tropic hormones. MH: 441 N: 482 Pituitary hormones MH: 442 N: 475 3

4 Pituitary hormones MH: 442 N: 476 Pituitary hormones Made in the hypothalamus: stored and released in the posterior lobe: ADH and oxytocin Released to the anterior lobe via the portal system: pituitary releasing and inhibi8ng hormones Tropic hormones are made in the anterior pituitary ACTH, PRL, TSH, LH, FSH, hgh MH: 442 N: 476 Human growth hormone IMAGE: MH: 445 N: 477 4

5 Human growth hormone Regulates growth, development and metabolism Affects almost every 8ssue S8mulates liver to release hormones (growth factors) Too much gigan8sm and acromegaly Too li^le pituitary dwarfism Synthe8c hgh from DNA recombina8on MH: 444 N: 488 Thyroid gland MH: 448 N: 485 Thyroid gland MH: 448 N: 486 5

6 Thyroid gland Two lobes on either side of the trachea Primary effect is to increase metabolism Affects mul8ple organs Hypothyroidism Too li^le T3, T4 produc8on Cre8nism in children Lethargic and frequently cold Weight gain MH: 448 N: 486 Thyroid gland Hyperthyroidism Too much T3, T4 produc8on Anxiety Insomnia Heat intolerance Weight loss Goitre Over s8mula8on of the thyroid by TSH Enlarges the thyroid MH: 448 N: 486 Thyroid gland Calcitonin A hormone released when calcium ion levels in the blood are too high S8mulates the uptake of calcium into the bones MH: 449 N: 487 6

7 Parathyroid glands 4 small glands a^ached to the thyroid Parathyroid hormone (PTH) released in response to decreasing blood calcium concentra8ons PTH is antagonis1c to calcitonin MH: 449 N: 487 Parathyroid glands MH: 449 N: 487 Adrenal glands MH: 451 N: 481 7

8 Adrenal glands MH: 451 N: 482 Adrenal medulla Short- term response to a fight- or- flight stress Sympathe8c nerves s8mulate the release of Epinephrine Cardiovascular s8mula8on, pupil dila8on, vascular dila8on of the skeletal muscles, conversion of glycogen to glucose Norepinephrine Regulates blood pressure MH: 451 N: 482 Adrenal cortex Long- term response to stress Hormones released in response to ACTH from the anterior pituitary Glucocor8coids Cor8sol: converts non- carbohydrate substrates (protein, fat) into glucose Mineralocor8coids Aldosterone: acts on the kidney to reabsorb sodium ions thereby drawing in more water to raise blood pressure MH: 454 N: 482 8

9 Pancrea8c hormones MH: 456 N: 478 Pancrea8c hormones MH: 457 N: 478 Pancrea8c hormones MH: 457 N: 478 9

10 Pancrea8c hormones Sca^ered among the exocrine 8ssue of the pancreas are the islets of Langerhans Beta cells produce insulin Released auer a meal to act on receptors to make the target cells permeable to glucose Stores glucose as glycogen in the liver and muscles Converts excess glucose to fat Alpha cells produce glucagon Antagonis8c to insulin Released when blood glucose is low MH: 457 N: 478 Diabetes Diabetes mellitus is characterized by frequent urina8on and loss of glucose in the urine Too much glucose in the blood is called hyperglycemia Other symptoms include blindness, and kidney failure Hypoglycemia results when the body cannot control the amount of insulin released Can rapidly progress to insulin shock and death MH: 459 N: 479 Diabetes Type I diabetes The autoimmune system produces an8bodies that a^ack and destroy the beta cells A gene8c disorder that requires insulin injec8ons AKA juvenile diabetes, or insulin- dependant diabetes MH: 459 N:

11 Diabetes Type I diabetes The autoimmune system produces an8bodies that a^ack and destroy the beta cells A gene8c disorder that requires insulin injec8ons AKA juvenile diabetes, or insulin- dependant diabetes Type II diabetes The insulin receptors of the body stops responding to insulin Generally hereditary; accounts for ~90% of all diabe8cs 459 Key terms endocrine glands hormones endocrine system nega8ve feedback mechanisms an8diure8c hormone (ADH) tropic hormones pituitary gland posterior pituitary anterior pituitary human growth hormone (hgh) thyroid gland thyroxine (T4) hypothyroidism hyperthyroidism thyroid- s8mula8ng hormone (TSH) goitre adrenal glands adrenal medulla epinephrine norepinephrine short- term stress response fight- or- flight response adrenal cortex long- term stress response cor8sol adrenocor8cotropic hormone (ACTH) Aldosterone pancreas islets of Langerhans beta cells alpha cells insulin glucagon diabetes mellitus hyperglycemia type 1 diabetes type 2 diabetes 11