Chapter 10: Endocrine System Martin Caon Examination Questions and Answers in Basic Anatomy and Physiology Third Edition

Martin Caon Examination Questions and Answers in Basic Anatomy and Physiology Third Edition Chapter 10: Endocrine System 10.1 Endocrine System and Hormones in General 1. Which statement below about hormones is true? a. Hormones are enzymes that catalyse reactions. b. Hormones are released into the blood circulation. c. Hormones affect all cells of the body. d. Hormones are released by neurones at synapses. Answer is B: Hormones are circulating messengers that are transported in blood. A particular hormone does not necessarily affect every cell in the body. Some (but not all) hormones are released by neurones, for example in the hypothalamus. 2. Which hormones are soluble in blood? a. Steroid hormones b. Hormones produced by the adrenal cortex c. The sex hormones d. Those released by the pituitary gland Answer is D: The pituitary gland releases peptide hormones which are soluble in blood. The other choices refer to steroid hormones which are insoluble in blood. They require transport via plasma proteins. 3. Which one of the following is NOT part of the endocrine system? a. The islets of Langerhans (pancreatic islets) b. The thyroid gland c. The acini cells of the pancreas d. The parathyroid glands Answer is C: The acini cells produce digestive enzymes. 4. What is the difference between an exocrine gland and an endocrine gland? a. An endocrine gland secretes neurotransmitters (an exocrine gland does not). b. An endocrine gland secretes via a tube to the destination (an exocrine gland does not). c. An exocrine gland secretes into the blood (an endocrine gland does not). d. An endocrine gland secretes into the blood (an exocrine gland does not). Answer is D: Endocrine glands secrete “circulating” hormones that secrete into the blood. 5. By what term are hormones derived from tyrosine also known? a. Amino acid derivatives b. Peptide hormones c. Steroid hormones d. Corticosteroids Answer is A: Catecholamines (adrenaline, noradrenaline), dopamine and thyroid hormone are all derived from tyrosine. 6. Which hormones have their receptors inside their target cell? a. Amino acid-based hormones b. Hormones with a membrane carrier mechanism or that are lipid soluble c. Steroid hormones and peptide hormones of less than 50 amino acids d. Lipid-soluble hormones Answer is B: Choice D is also correct but B is the better answer as thyroid hormones cross membrane by a carrier mechanism. 7. What effect does aldosterone have? a. It causes glucose to be absorbed from the blood. b. It causes Na+ to be absorbed in the kidneys. c. It causes Ca2+ to be absorbed from the gut. d. It causes K+ to be absorbed from the filtrate. Answer is B: Aldosterone causes reclamation of sodium ions from the filtrate and potassium to be secreted in exchange. 8. Which of the following is a part of the endocrine system? a. The thalamus b. The pancreatic islets (islets of Langerhans) c. The renal glands d. The salivary glands Answer is B: The pancreatic islets secrete the hormones insulin and glucagon. 9. Which of the following is an amino acid derivative hormone? a. Epinephrine b. Tyrosine c. Testosterone d. Prostaglandin Answer is A: Epinephrine is derived from the amino acid tyrosine (so tyrosine is a wrong answer). 10. Which statement below is true of steroid hormones? a. They do not have a specific receptor to bind with. b. They are not lipid soluble so bind to receptor proteins on the cell membrane. c. They are lipid soluble so diffuse through the cell membrane. d. They cross the cell membrane via a carrier mechanism. Answer is C: Steroids are lipid soluble so diffuse through the plasma membrane to bind to a receptor within the cell. 11. What effect does aldosterone have? It causes: a. Angiotensin to be formed from angiotensinogen b. Na+ to be absorbed from the filtrate c. Na+ and Ca2+ to be absorbed from the filtrate and K+ to be secreted into the filtrate d. Na+ to be absorbed from the filtrate and K+ to be secreted into the filtrate Answer is D: Aldosterone promotes the absorption of sodium from the filtrate while potassium (also a positively charged ion) is secreted to maintain electrical neutrality. 12. Which of the following is NOT part of the endocrine system? a. The thymus b. The pineal gland c. The acini cells of the pancreas d. The posterior pituitary gland Answer is C: The acini cells produce digestive enzymes. 13. Which statement applies to steroid hormones? a. They are transported and dissolved in blood. b. They bind to receptor proteins on the outside of the plasma membrane. c. They cross the plasma membrane by using a protein carrier mechanism. d. They bind to receptors in the cell cytoplasm or nucleus. Answer is D: As steroid hormones are lipid soluble, their receptors are inside the cell as they can cross the plasma membrane. 14. What is one mechanism of hormone action? a. They act as second messengers in the cytoplasm. b. They act as enzymes for reactions. c. They act as receptor proteins. d. They activate genes in the nucleus. Answer is D: Some hormones (corticosteroids) determine which genes are transcribed in the nucleus. 15. What is the effect of ADH (antidiuretic hormone)? a. Allows walls of collecting duct to become permeable to water b. Inhibits the reabsorption of Na+ c. Causes an increase in the volume of urine produced d. Promotes diuresis Answer is A: ADH causes more aquaporins to be inserted into the collecting duct walls which allow water molecules to pass through along the osmotic gradient. 16. Which one of the following is NOT true of peptide hormones? a. They are water soluble. b. They are derived from amino acids. c. Their receptors are located in the cell cytoplasm. d. They are transported and dissolved in blood. Answer is C: The receptors for peptide hormones are located on the plasma membrane as they are unable to penetrate the plasma membrane. 17. How do steroid hormones differ from amino acid-based hormones? a. Steroid hormones are water soluble, whereas amino acid-based hormones are not. b. The receptors for steroid hormones are only in the cytoplasm or the nucleus (and amino acid-based hormones are not). c. Steroid hormones are made only in the adrenal glands, while amino acid- based hormones are produced by a variety of glands. d. Steroid hormones activate a G-protein and exert their effect via “second messengers”, but the action of amino acid-based hormones results directly on binding to their receptor. Answer is B: Steroid hormones are lipid soluble so can enter the cell to bind to receptors located inside the cell. Amino acid-based hormones are not lipid soluble, so their receptors are located outside the cell on the plasma membrane. 18. Which of the following organ(s) are NOT endocrine organs? a. Renal b. Adrenal c. Thyroi d. Parathyroid Answer is A: Renal gland is another name for the kidney. 19. To which group of hormones does aldosterone belong? a. Catecholamines b. Glucocorticoids c. Mineralocorticoids d. Gonadocorticoids Answer is C: As aldosterone is concerned with the absorption of sodium ions, a “mineral” and it is produced by the adrenal cortex, it is termed a mineralocorticoid. 20. Where are the receptors for almost all of the amino acid-derived hormones located? a. On the mitochondria b. In the nucleus c. On the outside of the plasma membrane d. On the inside of the plasma membrane Answer is C: Amino acid-derived hormones cannot get through the plasma membrane, so they attach to receptors located on the outside of the membrane.