Ch. 16 – The Endocrine System – Answer Key

Ch. 16 – The Endocrine System – ANSWER KEY 1. True/False. The endocrine system works with the nervous system by responding quickly to stimuli in the body. FALSE. The endocrine system responds slowly to stimuli by using hormones as its communicator, which travel in blood and lymph. 2. Multiple Choice. Which of these is NOT an area that the endocrine system influences? a. Reproduction b. Growth and development c. Maintenance of electrolyte, water, and nutrient balance of blood d. Regulation of cellular metabolism and energy balance e. Mobilization of body defenses f. None of the above 3. True/False. The endocrine system uses ducts to communicate with its hormones. FALSE. The endocrine system lacks ducts. Sweat and saliva (not hormones) use ducts as transport. 4. Multiple Choice. Which of the following is a neuroendocrine organ? a. Pituitary b. Thyroid c. Thalamus d. Hypothalamus e. Gonads The hypothalamus serves both neural and endocrine functions. The pituitary, thyroid, parathyroid, adrenal, and pineal glands are strictly endocrine glands. The pancreas, gonads and placenta serve endocrine and exocrine functions. 5. True/False. Autocrines and paracrines are part of the endocrine system. FALSE. 6. True/False. Amino-acid based hormones are synthesized from cholesterol. FALSE. Steroid hormones (i.e. estrogens, testosterone, cortisol, etc.) are synthesized from cholesterol. Nonsteroids (aka amino-based hormones) consist of examples like NE, epinephrine, ADH, insulin, FSH, LH and TSH. 7. Short answer. Can hormones affect whichever cell they want? Why or why not? Hormones can only affect cells that have receptors for that specific hormone. Cells with receptors for a specific hormone are called target cells. 8. Multiple Choice. Which of the following is not a way that hormones influence cells. a. Alter plasma membrane permeability and/or membrane potential by opening or closing ion channels b. Stimulate synthesis of enzymes or other proteins c. Activate or deactivate enzymes d. Induce secretory activity e. Stimulate mitosis f. None of the above. 9. True/False. Water-soluble hormones can pass through the phospholipid bilayer. FALSE. Watersoluble hormones cannot enter the cell and instead act upon plasma membrane receptors or act via G protein second messengers. Lipid-soluble hormones can enter the cell and act on receptors inside there that then directly activate genes. 10. True/False. Adenylate cyclase is the first messenger of the 2nd messenger communication system used by hormones. FALSE. Hormones are the 1st messenger. Adenylate cyclase is the 2nd messenger. 11. True/False. When Ca2+ binds calmodulin, enzymes are activated that amplify the cellular response. TRUE 12. Multiple Choice. Arrange the following events into the correct order. 1. Diffuse into target cells and bind with intracellular receptors 2. Promote metabolic activities, or promote synthesis of structural proteins or proteins for export from cell 3. Receptor-hormone complex enters nucleus; binds to specific region of DNA 4. Prompts DNA transcription to produce mRNA 5. mRNA directs protein synthesis a. b. c. d. 1, 2, 3, 4, 5 1, 5, 2, 3, 4 1, 3, 4, 5, 2 5, 4, 3, 1, 2 13. Short Answer. What is up-regulation of target cells? What is down-regulation? Up-regulation—target cells form more receptors in response to low hormone levels Down-regulation—target cells lose receptors in response to high hormone levels 14. Multiple Choice. The endocrine gland is activated by all the following except _______________. a. Humoral stimuli - Changing blood levels of ions and nutrients directly stimulate secretion of hormones (i.e. low calcium causes PTH to be secreted by parathyroid gland) b. Neural stimuli - Sympathetic nervous system fibers stimulate adrenal medulla to secrete catecholamines c. Hormonal stimuli - Hormones stimulate other endocrine organs to release their hormones (i.e. Hypothalamic hormones stimulate release of most anterior pituitary hormones) d. Mitotic stimuli 15. True/False. The endocrine gland can override the nervous system’s commands. FALSE. It’s the other way around. 16. Short Answer. What are the three main ways that hormones are removed from the blood? a. Degrading enzymes b. Kidneys c. Liver 17. Fill-In. Hormones that work together on a target cell to be more effective are called synergistic. 18. Multiple Choice. Which portion of the pituitary gland is composed of glandular tissue? a. Posterior lobe b. Anterior lobe c. Both lobes d. Neither lobe 19. Fill-In. The nuclei of hypothalamus synthesize the two neurohormones oxytocin and antidiuretic hormone (ADH), which are then transported to and stored in the posterior pituitary lobe. 20. Fill In. The hypophyseal portal system carries releasing and inhibiting hormones to the anterior pituitary to regulate hormone secretion. If the anterior pituitary is told to release hormones, then it will release hormones (like GH, TSH, ACTH, FSH, LH, and PRL) through the secondary capillary plexus of the HPS which will then empty into the rest of the body’s bloodstream. 21. Short Answer. Give one function of oxytocin. a. Strong stimulant of uterine contraction b. Released during childbirth c. Hormonal trigger for milk ejection d. Acts as neurotransmitter in brain 22. Short Answer. Give one function of ADH. a. Inhibits or prevents urine formation b. Regulates water balance c. Targets kidney tubules  reabsorb more water d. Release also triggered by pain, low blood pressure, and drugs e. Not a function , but it’s inhibited by alcohol, diuretics (i.e. coffee… diuretics make you pee) f. High concentrations  vasoconstriction 23. Short Answer. What are the six anterior pituitary hormones and give a function for each one. a. Growth hormone (GH) i. Direct actions on metabolism (i.e. works against insulin by keeping glucose in the bloodstream; encourages fatty acids to be in the blood stream) and protein synthesis (growth). ii. Also indirectly helps formation of bone and skeletal muscle via IGF’s. b. Thyroid-stimulating hormone (TSH) or thyrotropin i. Stimulates normal development and secretory activity of thyroid ii. Note: Inhibited by rising blood levels of thyroid hormones that act on pituitary and hypothalamus c. Adrenocorticotropic hormone (ACTH) i. Stimulates adrenal cortex to release corticosteroids d. Follicle-stimulating hormone (FSH) i. Stimulates gamete (egg or sperm) production. e. Luteinizing hormone (LH) i. Promotes production of gonadal hormones. f. Prolactin (PRL) i. Stimulates milk production in women. 24. Fill-In. The thyroid gland consists of two lateral lobes connected by the isthmus. The gland is made of follicles that produce the glycoprotein thyroglobulin. The parafollicular cells also found in this gland produce the hormone calcitonin, which lowers blood calcium levels. [NOTE: Thyroglobulin is the precursor to thyroid hormone.] 25. Short Answer. Thyroid hormone affects virtually all cells in the body. What are some of the effects caused by TH? Give two examples. • Major metabolic hormone • Increases metabolic rate and heat production (calorigenic effect) • Regulation of tissue growth and development – Development of skeletal and nervous systems – Reproductive capabilities • Maintenance of blood pressure 26. True/False. Tyrosines, which are part of the thyroglobulin molecule, combine with chlorine molecules to eventually form T3 and T4. FALSE. Tyrosine binds with iodine (I2). 27. True/False. T4 is more active in the body than T3. FALSE. T3 is more active than T4 in the body. 28. True/False. Rising TH levels in the blood cause an inhibition of the release of Thyroid Stimulating Hormone (TSH). TRUE. 29. Multiple Choice. Which answer most accurately describes the role of calcitonin? a. Inhibits osteoclast activity and release of Ca2+ from bone matrix b. Stimulates osteoclast activity and release of Ca2+ from bone matrix c. Stimulates Ca2+ uptake and incorporation into bone matrix d. Inhibits Ca2+ uptake and incorporation into bone matrix e. Both A and C are correct. f. Both B and D are correct. 30. Short Answer. Give one to two of the main functions of parathyroid hormone (PTH). a. Stimulates osteoclasts to digest bone matrix and release Ca2+ to blood b. Enhances reabsorption of Ca2+ and secretion of phosphate by kidneys c. Promotes activation of vitamin D (by kidneys); increases absorption of Ca2+ by intestinal mucosa d. Rising Ca2+ levels in the blood shut off release of PTH. 31. FYI. The adrenal glands are broken up into two groups: the adrenal cortex and the adrenal medulla. a. The adrenal cortex is subdivided even further into (from superficial to deep) i. the zona glomerulosa ii. the zona fasciculata iii. the zona reticularis. b. Even deeper, we find the adrenal medulla. c. Below are images which show these zones and the primary hormones that they are responsible for: 32. Fill-In. The hormone aldosterone is made in the zona glomerulosa and is the most potent of mineralocorticoids. This hormone stimulates sodium reabsorption and water retention by the kidneys and the elimination of potassium. 33. True/False. Cortisol is often released in response to stress and causes an increase in the production of glucose (from fats and proteins). TRUE. 34. Short Answer. The adrenal medulla produces norepinephrine and epinephrine. What response(s) does each of those hormones cause? • Epinephrine stimulates metabolic activities, bronchial dilation, and blood flow to skeletal muscles and heart • Norepinephrine influences peripheral vasoconstriction and blood pressure 35. Multiple Choice. The pineal gland produces _________________. a. Epinephrine b. TSH c. Norepinephrine d. Melatonin e. Insulin 36. Fill-In. The Islets of Langerhans (pancreatic islets) have alpha cells that produce glucagon which raise blood glucose levels, while beta cells produce insulin which lower blood glucose levels. 37. Short Answer. The gonads produce steroid sex hormones. Give a function of estrogen and testosterone. a. Estrogen i. Maturation of reproductive organs ii. Appearance of secondary sexual characteristics iii. With progesterone, causes breast development and cyclic changes in uterine mucosa b. Testes produce testosterone i. Initiates maturation of male reproductive organs ii. Causes appearance of male secondary sexual characteristics and sex drive iii. Necessary for normal sperm production iv. Maintains reproductive organs in functional state