Human Anatomy and Physiology - Problem Drill 16: The Endocrine System

Transcription

1 Human Anatomy and Physiology - Problem Drill 16: The Endocrine System Question No. 1 of 10 The endocrine system is made up of a number of organs and glands. Which one of the following is not an organ or gland of the endocrine system? Question #01 A. Thymus gland. B. Pancreas. C. Thyroid gland. D. Suprarenal gland. E. Stomach. The thymus gland is involved in the development of T-Cells. B. Incorrect! The pancreas regulates blood sugar through the actions of the hormones, insulin and glucagon. The thyroid gland secretes T 4 and T 3, which are involved in metabolism. On the top of each kidney is a suprarenal gland. These glands secrete epinephrine and norepinephrine. E. Correct! The stomach is not part of the endocrine system. The endocrine system allows the various organ systems within the body to communicate with each other and to coordinate their activities. This is accomplished by means of endocrine organs, or glands, that secrete hormones. The overall effect of the endocrine system is to contribute to homeostasis, the maintenance of a stable internal environment.

2 Question No. 2 of 10 There are four different categories of hormones used as part of the endocrine system, and these different hormones perform a variety of functions in the body. Which of the following statements about the hormone depicted below is correct? Question #02 A. Luteinizing hormone is an example of an eicosanoid. B. Luteinizing hormone is synthesized from amino acids. C. Luteinizing hormone is an example of steroid hormone. D. This hormone functions by regulating body fluid composition. E. None of the answers are correct. Luteinizing hormone is an example of a hormone synthesized in the body from amino acids. B. Correct! Luteinizing hormone is an example of a hormone synthesized from amino acids. Steroid hormones are derivatives of cholesterol, such as estrogen. Luteinizing hormone is an example of a hormone synthesized in the body from amino acids. Luteinizing hormone stimulates the ovaries in women and the production of testosterone in men. Answer B is correct. Peptide hormones are hormones that are synthesized from amino acids. Like most proteins, they are processed in the endoplasmic reticulum, including glycosylation. Examples of peptide hormones include: (1) luteinizing hormone, which stimulates ovulation in women and testosterone production in males, and (2) antidiuretic hormone, which has the very important function of regulating the body s fluid retention.

3 Question No. 3 of 10 Eicosanoids are a group of hormones that are part of the endocrine system. This class of hormones has tremendous effects on the vascular system. Which of the following statements about eicosanoids is correct? Question #03 A. Eicosanoids are derived via the oxidation of fatty acids. B. FSH is an example of an eicosanoid. C. Arachidonic acid can be converted into prostaglandins, prostacyclins and steroid hormones. D. The primary enzyme involved in the formation of eicosanoids is PKA. E. The class of drugs, known as COX inhibitors, block the action of the PKA enzyme. A. Correct! Eicosanoids are derived via the oxidation of fatty acids. B. Incorrect! FSH or follicle-stimulating hormone is a glycoprotein. Arachidonic acid can be converted into prostaglandins and prostacyclins, but not steroid hormones. Cyclooxygenase is the primary enzyme for the production of eicosanoids. COX inhibitors are drugs used to inhibit the action of the cyclooxygenase enzyme. Eicosanoids are derived via the oxidation of fatty acids. Arachidonic acid can be converted into: (1) prostaglandins, which are involved in inflammation; (2) prostacyclins, which prevent the formation of the platelet plug; and (3) thromboxanes, which are vasoconstrictors. The formation of these eicosanoids is facilitated by the enzyme cyclooxygenase, which is the target of COX inhibitors, such as Aspirin. Eicosanoids are derived via the oxidation of fatty acids. The arachidonic acid enzyme, cyclooxygenase, is the target of COX inhibitors, such as Aspirin. Overall, eicosanoids affect enzyme processes in the extracellular fluid.

4 Question No. 4 of 10 The hypothalamus and pituitary gland make up the hypothalamus-pituitary system in endocrine physiology. Which of the following statements about the hypothalamus-pituitary system is correct? Question #04 A. Hormones and factors from the hypothalamus drive the production and secretion of hormones from the pituitary gland. B. Epinephrine is an example of a hormone secreted by the hypothalamus-pituitary system. C. The infundibulum separates the hypothalamus and the pituitary gland into two distinct, separate regions. D. The hypothalamus only regulates the function of the pituitary gland. E. All of the hormones and factors produced in the hypothalamus lead to the release of pituitary hormones. A. Correct! Hormones and factors from the hypothalamus drive the production and secretion of hormones from the pituitary gland. B. Incorrect! Examples of hormones and factors produced by the hypothalamus include: (1) growth hormone releasing hormone and prolactin-inhibiting factor. The hypothalamus and pituitary gland are connected through the infundibulum. In addition to regulating the function of the pituitary gland, the hypothalamus also contributes to the regulation of the endocrine cells in the suprarenal medulla. Prolactin-inhibiting factor is an example of a product of the hypothalamus that has an inhibitory action on the release of a pituitary hormones. The Hypothalamus-Pituitary system is the master control center of endocrine physiology. Hormones and signals from the hypothalamus drive pituitary hormone secretion. The hypothalamus receives nerve inputs from higher brain centers and then, in turn, exerts effects on the pituitary gland. Examples of hormones and factors produced by the hypothalamus include: (1) growth hormone releasing hormone - this targets the release of growth hormone from the pituitary gland and (2) prolactin-inhibiting factor - this factor inhibits the release of pituitary prolactin. Within the hypothalamus are autonomic centers that control the endocrine cells of the suprarenal medulla.

5 Question No. 5 of 10 A 37-year-old woman is diagnosed with a tumor that is located in the posterior lobe of her pituitary gland. Based on this information, which of the following statements is correct? Question #05 A. The levels of growth hormone would be decreased in this patient, as it is normally produced in the posterior lobe of the pituitary gland. B. The levels of LH and FSH would not be expected to be decreased in this patient. C. The production and release of prolactin would be abnormal in this patient, as it is produced by the posterior lobe. D. The four hormones produced by the posterior lobe of the pituitary gland would be decreased in this patient. E. The posterior lobe of the pituitary produces a total of 3 hormones. The levels of growth hormone in this patient would be expected to be normal, as it is not produced in the posterior lobe. B. Correct! The levels of LH and FSH would not be expected to be decreased in this patient, as these hormones are produced in the anterior lobe. Prolactin is produced in the anterior lobe of the pituitary; therefore, its secretion would not be altered in this patient. The posterior lobe of the pituitary gland produces a total of 2 hormones: Antidiuretic hormone (ADH) and Oxytocin. The posterior lobe of the pituitary gland produces a total of 2 hormones: Antidiuretic hormone (ADH) and Oxytocin. The posterior pituitary lobe, or neurohypophysis, receives stimulation through projections from the hypothalamus and through the local blood supply. There are 2 hormones produced in this region: (1) Antidiuretic hormone (ADH) this hormone is stored in secretory vesicles awaiting release. Its primary role is to regulate body water composition. ADH reduces water clearance in the kidneys; and (2) Oxytocin is released during labor in pregnancy and during breastfeeding. During labor, the hypothalamus stimulates the release of oxytocin from this region of the pituitary, and this hormone increases contractions in the uterus.

6 Question No. 6 of 10 Which portion of the endocrine system in the human body is depicted in the image below? Question #06 A. Thymus gland. B. Thyroid gland. C. Hypothalamus. D. Pineal gland. E. None of the answers are correct. The thymus gland is located in the center of the chest. B. Correct! The image depicts the thyroid gland, which is located in the neck on the anterior surface of the larynx. The hypothalamus is located in the diencephalon region of the brain. The pineal gland is located in the brain near the top of the brainstem. Answer B is correct. The thyroid gland is the largest endocrine gland in the body, and it is located in the neck on the anterior surface of the larynx. The thyroid s activity is controlled by the pituitary secretion of Thyroid-Stimulating Hormone. It controls body metabolism and protein production. The thyroid gland produces thyroxine (T 4) and Triiodothyronine (T 3). The element, iodine, is critical to the production of thyroxine. Iodine is the first key step in the biosynthesis of this hormone. This is the reason iodine was added to salt in North America, to prevent a condition called Goiter (which is caused by iodine deficiency).

7 Question No. 7 of 10 The thyroid gland regulates body metabolism, and it receives signals from the pituitary gland for the secretion of its hormones. Which of the following statements about the thyroid gland is correct? Question #07 A. The thyroid gland produces thyroxine (T 4), Triiodothyronine (T 3), and parathyroid hormone. B. The two hormones produced by the thyroid gland are thyroxine (T 4) and Triiodothyronine (T 3). C. The medical condition, known as goiter, is caused by an excess of iodine. D. Thyroglobulin is the special transport protein for thyroid hormones in the circulation. E. Once inside cells, the thyroid hormone, T 4, is converted into parathyroid hormone. The two hormones produced by the thyroid gland are thyroxine (T 4) and Triiodothyronine (T 3). B. Correct! The two hormones produced by the thyroid gland are thyroxine (T 4) and Triiodothyronine (T 3). Goiter is a condition caused by iodine deficiency; it is very rare in North America with iodine fortification. Thyroglobulin is the storage site for iodine in the thyroid tissue. Once inside cells, the thyroid hormone, T 4, is converted into T 3. The thyroid gland is the largest endocrine gland in the body, and it is located in the neck on the anterior surface of the larynx. The thyroid s activity is controlled by the pituitary secretion of Thyroid-Stimulating Hormone. It controls body metabolism and protein production. The thyroid gland produces thyroxine (T 4) and Triiodothyronine (T 3). The element, iodine, is critical to the production of thyroxine. Iodine is the first key step in the biosynthesis of this hormone. This is the reason iodine was added to salt in North America, to prevent a condition called Goiter (which is caused by iodine deficiency). Iodine enters the thyroid tissue and is sequestered inside cells as part of thyroglobulin. It is stored in the colloid within the thyroid gland. Upon thyroid stimulation, T 3 and T 4 are produced and released into the bloodstream. Upon entering cells, T 4 is converted to T 3. T 3 increases cardiac output and metabolism throughout the body.

8 Question No. 8 of 10 Which of the following statements about the portion of the endocrine system identified in the image below is correct? Question #08 A. The thyroid gland is identified in the image. B. Parathyroid hormone is produced by the glands identified in the image. C. Parathyroid hormone, produced by these glands, is involved in regulating the level of potassium in the blood. D. These glands are typically located on the anterior and posterior surfaces of the thyroid gland. E. The hormone produced by these glands is secreted more abundantly when blood calcium levels increase. The parathyroid glands are identified in the image. B. Correct! The image identifies the parathyroid glands, which produce parathyroid hormone. Parathyroid hormone functions in the regulation of blood calcium levels. The parathyroid glands are typically located on the posterior surface of the thyroid gland. The release of parathyroid hormone decreases as blood calcium levels increase. On the posterior surface of the thyroid gland, there are 4 or more small glands, known as the parathyroid glands. The parathyroid glands produce Parathyroid Hormone (PTH). PTH is involved in calcium homeostasis. Parathyroid Hormone causes the release of calcium into the bloodstream by stimulating bone osteoclast activity. The release of PTH is regulated by calcium levels in the blood. As the blood calcium concentration increases, the release of PTH decreases. As blood calcium levels decrease to a certain concentration, in part due to deposition in bone, the PTH levels increase.

9 Question No. 9 of 10 The suprarenal glands are located on the top of each kidney and they receive their own blood supply and innervation. Which of the following statements about the suprarenal glands is correct? Question #09 A. Both the medulla and cortex of the suprarenal gland are innervated by the sympathetic nervous system. B. The cortex of the suprarenal gland produces epinephrine and norepinephrine. C. The suprarenal cortex produces epinephrine, glucocorticoids and mineralcorticoids. D. The release of epinephrine from the suprarenal gland is regulated by the hormone, ACTH, from the thyroid gland. E. None of the answers are correct. A. Correct! The facial nerve, vagus nerve, and the glossopharyngeal nerve normally transmit gustatory nerve impulses. B. Incorrect! The hormones of the suprarenal cortex are glucocorticoids, mineralcorticoids and precursors to sex steroids. The hormones of the suprarenal cortex are glucocorticoids, mineralcorticoids and precursors to sex steroids. ACTH from the pituitary gland regulates the release of cortisol from the suprarenal cortex. One of the answers is correct. The suprarenal (adrenal) glands are located on top of the kidneys; they receive their own blood supply and are divided into 2 regions. The gland is divided into the adrenal medulla and the adrenal cortex. Both of these regions receive nerve impulses from the sympathetic nervous system. The suprarenal cortex is the outermost layer of the adrenal gland, and it includes the following regions: zona glomerulosa, which is the outermost region; zona fasciculata; and the zona reticularis. The hormones of the cortex include: (A) Glucocorticoids (Cortisol) cortisol is involved in metabolic processes, such as lipolysis and gluconeogenesis, (B) Mineralcorticoids (Aldosterone) aldosterone is a hormone that stimulates the kidneys to retain sodium and potassium, and (C) Precursors to sex steroids, which are pro-hormones for estrogen and testosterone production. The suprarenal medulla makes up the center of the adrenal gland. It produces the following hormones: (A) Epinephrine is a fight or flight hormone. When it is secreted, it prepares the body for action by increasing heart rate and delivering more blood to skeletal muscles, and (B) Norepinephrine is both a hormone and neurotransmitter. As a hormone, it acts synergistically with epinephrine and also increases blood pressure by vasoconstriction.

10 Question No. 10 of 10 The gonads produce the sex hormones that are involved in the development of male and female characteristics. Which of the following statements about the gonads is correct? Question #10 A. The hormone, GNRH, from the pituitary gland stimulates the ovaries to produce estrogen and progesterone. B. Androgen is a generic term for hormones that are involved in the development of female physical characteristics. C. The ovaries are stimulated to produce hormones, by human chorionic gonadotropin produced by the placenta during pregnancy. D. The female hormone, progesterone, is produced by the granulosa cells of the ovary. E. The corpus luteum produces estrogen in response to LH and FSH. GNRH is released by the hypothalamus and it stimulates the pituitary gland to produce LH and FSH. B. Incorrect! Androgen is a generic term for hormones responsible for male physical characteristics. C. Correct! Human chorionic gonadotropin, produced by the placenta during pregnancy, drives ovary hormone production. Progesterone is produced in the corpus luteum and its production is regulated by LH and FSH. Estrogen is produced by the granulosa cells in the ovary. Androgen is a generic term for hormones responsible for male physical characteristics. Testosterone is the primary androgen that is produced from the testes, under control of the pituitary gland. The ovaries in the female produce estradiol (estrogen) and progesterone. These hormones function, along with LH and FSH from the pituitary gland, to develop female characteristics and drive the menstrual cycle. Estrogen is produced by the granulosa cells in the ovary, and its levels in the blood have a negative feedback on the hypothalamus-pituitary system. Progesterone is produced in the corpus luteum and its production is regulated by LH and FSH.