BSC 109 1st Edition Lecture 19Outline of Last Lecture I. Receptors receive and convert stimuliII. CNS interprets nerve impulses based on origin and frequencyIII. Mechanoreceptors detect touch, pressure, and vibration (Skin receptors)IV. Mechanoreceptors detect limb position, muscle length, and tensionV. Thermoreceptors detect temperatureVI. Pain receptors signal discomfortVII. Taste: chemoreceptors bind with dissolved substancesVIII. Hearing: mechanoreceptors detect sound wavesIX. Disorders of the earX. Vision: detecting and interpreting visual stimuliOutline of Current Lecture I. The endocrine system produces hormonesII. Hormones are classified as steroid and nonsteroidIII. The hypothalamus and the pituitary glandIV. The pancreas secretes glucagon, insulin, and somatostatinV. The adrenal medulla: epinephrine and norepinephrineVI. Thyroid and parathyroid glandsVII. Iodine deficiency can cause goiterVIII. Important hormonesIX. Disorders of the endocrine systemCurrent LectureChapter 13: The Endocrine SystemX. The endocrine system produces hormonesA. Endocrine system: collection of specialized cells and tissues that secrete hormonesB. Endcrine glands: ductless organs that secrete hormones into blood, interstitial fluid, lymphC. Hormones1. Chemical messengers secreted by endocrine glands2. Circulate in the bloodstream3. Act on specific cells in the body (target cells) that have the appropriate hormone receptorThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.4. Hormones have access to every cell5. Each hormone acts only on specific cells6. Only specific cells have receptors for specific hormones7. Endocrine control is slower than nervous system8. Endocrine and nervous system interactXI. Hormones are classified as steroid and nonsteroidA. Steroid hormones1. Structurally related to cholesterol2. Lipid soluble3. Enter target cells, bind to intracellular receptor4. Activate specific genes to produce specific proteins5. Slower acting than nonsteroid hormones; minutes to hoursB. Nonsteroid hormones1. Structurally related to proteins2. Lipid insoluble3. Bind to receptors on target cell membranes4. Work through intermediate mechanisms to activate existing enzymes5. May involve a “second messenger” within the cell, such as cyclic AMP6. Faster action than steroid hormones; seconds to minutesXII. The hypothalamus and the pituitary glandA. Hypothalamus1. Homeostatic control center of the brain2. Links nervous system and endocrine system3. Produces two hormones of its own4. Monitors and controls hormone secretions of the pituitary `glandB. Pituitary gland1. “Master” gland2. Secretes 8 different hormones that regulate other endocrine organs3. Two lobes: posterior and anteriorC. Posterior pituitary stores ADH and oxytocin1. Posterior pituitary is connected to hypothalamus by neuroendocrine cells2. Posterior pituitary hormones: nonsteroidala) Antidiuretic hormone (ADH) conserves water in kidneys and regulates water balance in bodyb) Oxytocin causes uterine contractions during labor and milk ejection through neuroendocrine reflexD. Anterior pituitary produces 6 key hormones1. Prolactin stimulates development of mammary glands and milk production2. Growth hormonea) Has widespread effects on bodyb) Major effects on bone, musclec) Most of its growth-promoting effects occur during childhood and adolescenceE. Pituitary disorders1. Diabetes insipidus: hyposecretion of ADH results in inability to conserve water appropriately2. Gigantism: hypersecretion of growth hormone in childhood3. Acromegaly: excessive growth hormone over a long period in adults4. Pituitary dwarfism: hyposecretion of growth hormone; treated by administration of GH throughout childhoodXIII. The pancreas secretes glucagon, insulin, and somatostatinA. The pancreas has both exocrine and endocrine functionsB. Pancreatic hormones are involved in regulating blood glucose levelsC. Endocrine cells in islets of Langerhans within the pancreas secrete the following three hormones:1. Alpha cells: secrete glucagona) Raises blood sugarb) Causes breakdown of glycogen to glucose in liver2. Beta cells: secrete insulina) Lowers blood sugarb) Promotes uptake of sugar by cells in liver, muscle, and adipose tissuec) Promotes conversion of glucose into glycogen, proteins, fat3. Delta cells: secrete somatostatin a) Inhibits secretion of glucagon and insulin, regulates other hormonesXIV. The adrenal medulla: epinephrine and norepinephrineA. Neuroendocrine organB. Secretion stimulated by sympathetic nervous systemC. Hormones: nonsteroidal are epinephrine and norepinephrine (they enhance function of sympathetic nervous system and fight-or-flight response)XV. Thyroid and parathyroid glandsA. Thyroid located just below larynx in neckB. Parathyroid glands embedded in back of thyroidC. Both thyroid and parathyroid are involved in calcium balanceD. Thyroid is also involved in regulating metabolismXVI. Iodine deficiency can cause goiterA. Iodine is required for the production of active thyroid hormonesB. Inadequate dietary iodine leads to underproduction of thyroid hormonesC. The feedback response to inadequate thyroid hormone is for the hypothalamus and pituitary to further stimulate the thyroid gland in a vicious cycle that causes hypertrophy of the thyroid (goiter)XVII. Important hormonesA. Testes produce testosteroneB. Ovaries produce estrogen and progesteroneC. Pancreas produces glucagon, insulin, and somatostatinD. Adrenal medulla produces epinephrine and norepinephrineE. Kidneys produce erythropeoitinF. Histamine is secreted by mast cells in response to injury or allergyXVIII. Disorders of the endocrine systemA. Diabetes mellitus1. Disorder of blood sugar regulation2. Type 1a) Pancreas does not produce enough insulinb) Treated with insulin injections3. Type 2a) Non-insulin dependentb) Treated with lifestyle changes, variety of medications4. Inability to get glucose into cells where it can be used, results in high blood sugar levels5. Glucose and excess water appear in the