ZOOL. 252 EXAM QUESTIONS - ENDOCRINE SYSTEM (set 1)

NOTE - Endocrine system questions are typically included in questions over other organ systems too.

[1-9] [10-19] [20-29] [30-39] [40-49] [50-59] [60-69] [70-79] [80-89] [90-99] [100-109] [110-119] [120-129]

[BATCH 971]

[BATCH 972]

[BATCH 961]

[Endocrine System (set 2)]

[Exam Questions - Information Page]

[A&P home page]

webmaster: amills@utm.edu

BATCH 931

[1-9] [10-19] [20-29] [30-39] [40-49]

1-9

1. Compared to the nervous system, the endocrine system sends signals:
   1. over shorter distances
   2. at a faster rate
   3. to a wider variety of cell types in the body
   4. which exert effects for less time
   5. of an electrochemical nature [top]

2. Which endocrine gland secretes neurohormones?
   1. posterior pituitary
   2. anterior pituitary
   3. gonads
   4. parathyroids
   5. adrenals [top]

3. Which organ performs both endocrine and major non-endocrine functions?
   1. pineal
   2. adrenal
   3. thyroid
   4. parathyroid
   5. heart [top]

4. The chemical flutamide binds specifically to testosterone receptors. If a man is injected with flutamide, what would probably happen?
   1. the testes would not be able to secrete testosterone
   2. the target tissues would not be able to respond to testosterone
   3. the testes would not be able to manufacture testosterone
   4. nothing, testosterone receptors are unnecessary [top]

5. Production of which hormone would be less affected in a person whose diet is deficient in proteins?
   1. GnRH
   2. FSH
   3. prolactin
   4. oxytocin
   5. estrogen [top]

6. Production of which hormone would be most affected in a person taking anti-cholesterol drugs?

1. LH
2. inhibin
3. relaxin
4. progesterone
5. PRH [top]

7. Estrogen secretion is triggered by ______________________________________________ stimuli.
   1. hormonal
   2. humoral
   3. neural [top]

8. Based on its name, the best guess as the source of corticotropin releasing hormone is:
   1. hypothalamus
   2. anterior pituitary
   3. posterior pituitary
   4. adrenal cortex
   5. adrenal medulla [top]

9. Based on its name, the best guess as the source of adrenocorticotropic hormone is:
   1. hypothalamus
   2. posterior pituitary
   3. anterior pituitary
   4. adrenal medulla
   5. adrenal cortex [top]

10-19

10. PRH directly stimulates:
    1. secretion of GnRH
    2. secretion of prolactin
    3. secretion of oxytocin
    4. production of milk
    5. ejection of milk [top]

11. Injection of which hormone will induce uterine contractions necessary for delivery of a baby?
    1. oxytocin
    2. prolactin
    3. estrogen
    4. progesterone
    5. relaxin [top]

12. Secretion of prolactin is directly stimulated by:
    1. a releasing hormone
    2. neural stimulation
    3. humoral stimulation
    4. estrogen
    5. relaxin [top]

13. Posterior pituitary hormones are secreted in response to:
    1. releasing hormones
    2. neural stimulation
    3. humoral stimulation
    4. negative feedback
    5. positive feedback [top]

14. Egg and sperm production are both directly stimulated by:
    1. LH
    2. FSH
    3. GnRH
    4. progesterone
    5. testosterone [top]

15. Secretion of estrogen and testosterone are both directly stimulated by:
    1. LH
    2. FSH
    3. GnRH
    4. PRH
    5. PIH [top]

16. Besides the gonads, which endocrine gland is another source of testosterone?
    1. adrenal cortex
    2. adrenal medulla
    3. hypothalamus
    4. placenta
    5. pancreas [top]

17. The term "negative feedback" could be accurately applied to the ______ effect of ______ on ______.
    1. inhibitory; inhibin; FSH
    2. inhibitory; PIH; prolactin
    3. inhibitory; estrogen; GnRH
    4. stimulatory; estrogen; PRH
    5. stimulatory; GnRH; LH [top]

18. Female genitals develop in a fetus as a result of the_________________of__________________.
    1. presence; estrogen
    2. presence; progesterone
    3. presence; testosterone
    4. absence; testosterone
    5. absence; estrogen [top]

19. A target of relaxin is:
    1. cervix
    2. myometrium
    3. mammary glands
    4. urethral sphincter
    5. ductus deferens [top] [10]

20-29

20. Androgen binding protein is produced by the __________________________________ cells.
    1. Sertoli
    2. interstitial
    3. epididymis
    4. spermatogonia [top]

21. Decline in estrogen and progesterone triggers:
    1. menstrual phase
    2. ovulation
    3. proliferative phase
    4. secretory phase
    5. luteal phase [top]

22. Which hormone can have either a negative or a positive feedback effect, depending on how much is present?
    1. estrogen
    2. progesterone
    3. FSH
    4. LH
    5. GnRH [top]

23. The testes normally develop in a male fetus as a result of action of:
    1. testosterone
    2. inhibin
    3. androgen binding protein
    4. estrogen
    5. genes on the Y chromosome [top]

24. A target of PIH is the:
    1. anterior pituitary
    2. posterior pituitary
    3. hypothalamus
    4. mammary glands
    5. ovaries [top]

25. List and briefly explain the ovarian and uterine cycles, explaining the hormonal triggers for each phase. Does one cycle follow the other or do they occur simultaneously? Do male reproductive organs undergo similar cycles? [top]

26. An effect of human chorionic gonadotropin is to:
    1. stimulate secretion of GnRH
    2. stimulate growth of the placenta
    3. stimulate development of the embryo
    4. stimulate secretion of progesterone
    5. inhibit secretion of estrogen [top]

27. Sunlight inhibits the secretion of ______________________________________.
    1. chorionic gonadotropin
    2. melatonin
    3. growth hormone
    4. calcitonin
    5. progesterone [top]

28. Hypersecretion of growth hormone causes:
    1. acromegaly in children
    2. acromegaly in adults
    3. dwarfism in children
    4. gigantism in adults
    5. dwarfism in adults [top]

29. Calcitonin secretion is regulated by _____________________________________ stimuli.
    1. hormonal
    2. neural
    3. humoral [top] [20]

30-39

30. A hormone associated with maturation of white blood cells is:
    1. interferon
    2. erythropoietin
    3. interleukin
    4. perforin
    5. thrombopoietin [top]

31. Which hormone stimulates growth of a child's bones and muscles?
    1. calcitonin
    2. growth hormone
    3. melatonin
    4. chorionic gonadotropin
    5. progesterone [top]

32. Which of the following is NOT a target of ANF?
    1. heart
    2. kidney
    3. blood vessels
    4. adrenal cortex
    5. posterior pituitary [top]

33. Estrogen effects on the urinary system are most similar to the effects of:
    1. ADH
    2. angiotensin II
    3. aldosterone
    4. ANF
    5. testosterone [top]

34. Vasopressin is also known as:
    1. ADH
    2. aldosterone
    3. ANF
    4. angiotensin II
    5. oxytocin [top]

35. Insulin secretion is stimulated by ______________________________________________factors.
    1. humoral
    2. hormonal
    3. neural [top]

36. What effect does epinephrine have on bronchioles?
    1. increases resistance
    2. decreases resistance
    3. stimulates contraction
    4. stimulates O₂ unloading
    5. stimulates O₂ loading [top]

37. If you are stranded in the desert for hours, with no water to drink:
    1. your ADH secretion will increase
    2. your ADH secretion will decrease [top]

38. Which hormone stimulates reabsorption of Na⁺ from sweat?
    1. antidiuretic hormone
    2. atrial natriuretic factor
    3. aldosterone
    4. testosterone
    5. melatonin [top]

39. Given that hormones trigger smooth muscle contraction, for example during lactation and nursing, why don’t hormones trigger skeletal muscle contraction?
    1. skeletal muscle does not contain any hormone receptors
    2. skeletal muscle does not contain an adequate blood supply for hormone delivery
    3. hormonal action occurs too quickly compared to nervous system action
    4. hormonal action occurs too slowly compared to nervous system action [top] [30]

40-49

40. What prevents non-target organs from responding to a particular hormone?
    1. the capillary beds of the target organ alone are permeable to the hormone
    2. hormones will not be transported to non-target organs
    3. only the target organ cells contain receptor molecules for the hormone
    4. only target organ cells are permeable to the hormone
    5. nothing, all tissues respond to all hormones [top]

42. A target of gonadotropin releasing hormone (GnRH) is:
    1. anterior pituitary
    2. posterior pituitary
    3. gonads
    4. adrenal cortex
    5. adrenal medulla [top]

43. The hormone below regulated primarily by neural stimulation is:
    1. FSH
    2. LH
    3. oxytocin
    4. prolactin
    5. none of the above [top]

46. The source of the hormone relaxin is:
    1. anterior pituitary
    2. posterior pituitary
    3. placenta
    4. adrenal cortex
    5. corpus luteum [top]

47. Pregnancy tests using urine are based on detection of:
    1. estrogen
    2. progesterone
    3. HCG
    4. oxytocin [top]

48. Hypersecretion of growth hormone in adults results in:
    1. gigantism
    2. dwarfism
    3. acromegaly
    4. Turner syndrome
    5. diabetes mellitus [top]

BATCH 971

[50-59] [60-69] [70-79] [80-89] [90-99]

49. Based on my studies of endocrinology, my favorite endocrine organ is:
    1. the pituitary
    2. the thyroid
    3. the adrenals
    4. the gonads
    5. the pineal gland [top] [40]

50-59

50. In the process of protein hormone synthesis which of the following cell organelles is the site of mRNA translation into an amino acid chain?
    1. mitochondria
    2. rough endoplasmic reticulum
    3. Golgi apparatus
    4. nucleus
    5. none of the above [top]

51. Both the nervous and endocrine systems function in regulation of cellular activity. Which of the following characteristics best describes the endocrine system?
    1. uses chemical signals
    2. relatively slow speed of response
    3. affects most cells of the body
    4. all of the above
    5. none of the above [top]

52. Which of the following major physiological processes are regulated by endocrine systems?
    1. water and electrolyte metabolism
    2. immune system responses
    3. reproduction
    4. all of the above
    5. none of the above [top]

53. The general mechanisms of action of steroid hormones includes which of the following?
    1. direct gene activation
    2. adenylate cyclase system activation
    3. phospholipase system activation
    4. second messenger system activation
    5. none of the above [top]

54. Hypothalamic CRH regulation of pituitary ACTH is an example of which type of regulation?
    1. humoral
    2. neural
    3. hormonal
    4. all of the above
    5. none of the above [top]

55. Which of the following factors are determinants of hormone action?
    1. rate of hormone secretion
    2. rate of hormone clearance
    3. number of available receptors
    4. all of the above
    5. none of the above

56. What do the hormones CRH, TRH, GnRH, and GHRH share in common?
    1. all are steroids
    2. all are hypothalamic releasing hormones
    3. all are pituitary products
    4. all are "tropic" hormones
    5. none of the above [top]

57. In addition to thyroid hormone, the thyroid gland is also the source of which important hormone?
    1. glucagon
    2. calcitonin
    3. parathyroid hormone
    4. somatostatin
    5. none of the above [top]

58. Hyposecretion and/or receptor resistance to which of the following hormones is characterized by polyuria, polydipsia and polyphagia?
    1. glucagon
    2. calcitonin
    3. ADH
    4. insulin
    5. none of the above [top]

59. A deficiency in antidiuretic hormone results in which of the following syndromes?
    1. Grave’s disease
    2. acromegaly
    3. Addison’s disease
    4. Cushing’s disease
    5. diabetes insipidus [top] [50]

60-69

60. Which of the following hormones is not a product of the anterior pituitary?
    1. thyroid stimulating hormone
    2. oxytocin
    3. growth hormone
    4. prolactin
    5. none of the above

61. Which of the following hormones increases long bone growth, muscle mass and fat utilization?
    1. growth hormone
    2. calcitonin
    3. insulin
    4. glucagon
    5. none of the above [top]

62. The primary effect of a prolactin deficiency would be:
    1. galactorrhea
    2. infertility
    3. limited milk production
    4. elevated estrogen levels
    5. none of the above [top]

63. The hormone that is important to regulating uterine contractions and the initiation of labor is:
    1. somatomedin
    2. gonadotropin releasing hormone
    3. luteinizing hormone
    4. oxytocin
    5. none of the above [top]

64. A syndrome characterized by excessive urine production, dehydration, and hypernatremia with normal glucose regulation, would reflect a deficiency in which hormone?
    1. thyroid hormone
    2. antidiuretic hormone
    3. cortisol
    4. aldosterone
    5. none of the above [top]

65. What is the source of melatonin, a hormone important to synchronizing our light-dark cycles?
    1. pineal gland
    2. pituitary gland
    3. thyroid gland
    4. basal cells of the skin
    5. none of the above [top]

66. The synthesis of which hormone includes cell secretion of a product, modification of that product, endocytosis of the modified product and then exocytosis of the final hormone?
    1. calcitonin
    2. ACTH
    3. insulin
    4. thyroid hormone
    5. none of the above [top]

67. The hormone important to calcium metabolism which increases plasma Ca levels by increasing osteoclast activity, increasing intestinal Ca absorption and increasing renal Ca absorption is:
    1. calcitonin
    2. glucagon
    3. thyroid hormone
    4. parathyroid hormone
    5. none of the above [top]

68. The source of calcitonin is:
    1. chief cells
    2. parafollicular or C cells
    3. alpha cells
    4. delta cells
    5. none of the above [top]

69. The adrenal steroid released in response to increased plasma potassium levels, decreased plasma Na or an increase in angiotensin II levels is:
    1. aldosterone
    2. androstenedione
    3. cortisol
    4. glucocorticoid
    5. none of the above [top] [50] [60]

70-79

70. Overproduction of this adrenal steroid results in precocious sexual maturation in boys and development of masculine facial and body hair patterns in females.
    1. aldosterone
    2. androstenedione
    3. cortisol
    4. estrogen
    5. none of the above [top]

71. A deficit in which hormone system results in myxedema in adults and dis-proportionate growth, retardation or cretinism in children?
    1. thyroid hormone
    2. growth hormone
    3. insulin
    4. IGF-1
    5. none of the above

72. The symptoms characterizing a patient with a pituitary tumor resulting in overproduction of ACTH would be characteristic of which of the following syndromes?
    1. diabetes insipidus
    2. diabetes mellitus
    3. Addison’s disease
    4. Cushing’s disease
    5. Grave’s disease [top]

73. An adult male complained to his physician of general muscle weakness. Upon examination and lab tests he was found to be hypertensive and hypokalemic. Further examination revealed a tumor on his left adrenal gland. What is the likely diagnosis?
    1. hyperinsulinemia
    2. hypercorticolism
    3. hyperaldosteronism
    4. hypoaldosteronism
    5. none of the above [top]

74. Which of the following endocrine systems is directly regulated by the sympathetic nervous system?
    1. adrenal cortex
    2. adrenal medulla
    3. thyroid gland
    4. pineal gland
    5. none of the above [top]

75. The effects of epinephrine and norepinephrine are mediated by multiple subtypes of receptors designated as either alpha or beta. Which of the beta subtypes mediate the effect of epinephrine to increase heart rate and overall cardiac contractility?
    1. beta-1
    2. beta-2
    3. beta-3
    4. beta-4
    5. none of the above [top]

76. The primary product of the pancreatic beta cells, which has been dubbed the "hypoglycemic hormone," would be:
    1. insulin
    2. glucagon
    3. cortisol
    4. somatomedin-C
    5. none of the above

77. The release of the which of the following hormones is directly stimulated by a decrease in plasma glucose concentrations?
    1. insulin
    2. glucagon
    3. cortisol
    4. growth hormone
    5. none of the above [top]

78. A syndrome characterized by hyperglycemia with polyuria, polydipsia and polyphagia would most likely reflect:
    1. glucagon hypersecretion
    2. insulin hypersecretion
    3. glucagon hyposecretion
    4. insulin hyposecretion
    5. none of the above [top]

79. A hormone released from the heart that acts to inhibit renal sodium reabsorption is:
    1. cholecalciferol
    2. atrial natriuretic peptide
    3. C-peptide
    4. cholecystokinin
    5. none of the above [top] [50] [70]

80-89

80. The one factor most important to regulation of erythropoiesis is:
    1. serotonin
    2. bilirubin
    3. erythropoietin
    4. ferritin
    5. none of the above [top]

81. The basis for the most common type of diabetes mellitus, termed Type II or non-insulin-dependent diabetes mellitus, may be:
    1. inadequate insulin production
    2. insulin excess
    3. response tissue resistance to insulin
    4. a and c
    5. a, b and c [top]

82. Which hormone transduction mechanism involves Ca as a "third messenger?"
    1. adenylate-cyclase, cAMP
    2. phospholipase system
    3. direct gene activation
    4. all of the above
    5. none of the above

83. Which of the following syndromes is associated with growth hormone overproduction in an adult?
    1. acromegaly
    2. gigantism
    3. Cushing’s disease
    4. chronic hypoglycemia
    5. none of the above [top]

84. Which of the following is not considered to be an important effect of thyroid hormones?
    1. increase metabolism rate
    2. regulation of hepatic glucose metabolism
    3. regulate adrenergic receptors and blood pressure
    4. support or enhance tissue growth and development
    5. none of the above [top]

85. True Addison’s disease, which is characterized by hypoglycemia and hyponatremia, reflects a deficit in which hormone(s)?
    1. cortisol
    2. testosterone
    3. glucagon and insulin
    4. cortisol and aldosterone
    5. aldosterone [top]

86. The overall effect of insulin is to:
    1. decrease plasma glucose
    2. increase plasma glucose
    3. decrease glucagon
    4. decrease cortisol
    5. none of the above [top]

87. The primary effect of thyroid stimulating hormone (TSH) on the follicular cells of the thyroid is to:
    1. increase membrane permeability
    2. increase thyroid binding globulin production
    3. increase thyroglobulin production
    4. increase cellular metabolism
    5. none of the above [top]

88. In what way are the hormones of the posterior pituitary and the hypothalamic releasing hormones TRH, CRH, GnRH and GHRH similar?
    1. all regulate anterior pituitary function
    2. all are tropic hormones
    3. all are synthesized in the hypothalamus
    4. none have direct effects on a target tissue
    5. none of the above [top]

89. Identify the major regions of the adrenal gland, the primary product(s) of each region and characterize the principle effects of each product. [top] [50] [80]

90-99

90. Outline the regulation cascades, including names and sources for each of the following: cortisol, thyroid hormone, and estrogen. [top]

91. Outline similarities and differences between the effects of cortisol excess from hypoinsulinemia (diabetes mellitus) [top]

92. List the major hormones involved and explain why adrenal medullary products are said to be important to acute stress responses while adrenal cortical products are more important in long-term responses to stress. [top]

93. Outline the major components of the two primary signal transduction mechanisms employed by peptide (protein) hormones and give two examples of hormones that use each system. [top]

94. Outline the hormonal regulation of erythropoiesis. [top]

BATCH 972

[100-109]

95. Which of the following chemical mediators would not serve to increase arterial blood pressure?
    1. epinephrine
    2. antidiuretic hormone
    3. angiotensin II
    4. nitric oxide
    5. none of the above [top]

96. Which portion of the renin-angiotensin-aldosterone system serves to indirectly mediate long-term regulation of blood pressure?
    1. renin
    2. angiotnesinogen
    3. angiotensin II
    4. aldosterone
    5. none of the above [top]

97. Normally menstruation occurs when:
    1. plasma levels of estrogen and progesterone decrease
    2. plasma levels of FSH decrease
    3. plasma estrogen and progesterone levels increase
    4. the corpus luteum increases estrogen production
    5. none of the above [top]

98. The actual "trigger" for ovulation is:
    1. a surge in plasma progesterone levels
    2. a precipitous decline in plasma LH and FSH levels
    3. a surge in plasma LH and FSH levels
    4. a rapid decrease in plasma estrogen levels
    5. none of the above [top]

99. Which portion of the renin-angiotensin-aldosterone system serves to indirectly mediate long-term regulation of blood pressure?
    1. renin
    2. angiotensinogen
    3. angiotensin II
    4. aldosterone
    5. none of the above [top] [50] [90]

100-109

100. The adrenal steroid released in response to increased plasma potassium levels, decreased plasma Na or an increase in angiotensin II levels is:
     1. aldosterone
     2. androstenedione
     3. cortisol
     4. estrogen
     5. none of the above [top]

101. Which of the following is not an anterior pituitary hormone?
     1. ACTH
     2. ADH
     3. LH
     4. FSH
     5. none of the above [top]

102. In terms of overall blood pressure regulation, explain how the renin-angiotensin-aldosterone system can be important to both short-term regulation of blood pressure, renal blood flow and GFR, and also renal mechanisms for sodium regulation and long-term regulation of blood pressure. [top]

BATCH 961

[100-109] [110-119] [120-129]

103. Which form of communication is mediated by local hormones called cytokines?

1. Paracrine communication
2. Direct communication
3. Endocrine communication
4. Synaptic communication [top]

104. This form of communication is mediated by gap junctions.
     1. Paracrine communication
     2. Direct communication
     3. Endocrine communication
     4. Synaptic communication [top]

105. Which of the following is/are the definitive requirement(s) before a chemical is classified as a hormone?

1. it binds to a receptor with low affinity
2. it is released into the blood stream
3. it is produced only by purely endocrine tissue
4. it must be constructed from amino acids
5. c and d are both correct [top]

106. Which of the following endocrine organs is called a neuroendocrine organ?

1. thyroid
2. adrenal cortex
3. hypothalamus
4. gonads [top]

107. Estrogens are made from modified…

1. amino acids
2. cholesterol
3. fatty acids
4. all of the above
5. a and b only [top]

108. In the cyclic AMP second messenger system, which of the following will add phosphate groups to specific target proteins?

1. G-protein
2. Cyclic AMP
3. Protein kinase A
4. The hormone receptor complex [top]

109. A patient at the local doctors office is suffering from chronic high levels of blood calcium. Even when calcium intake is reduced, blood calcium levels remain high. A bone scan is ordered and reveals that his bones are abnormally thin. Which endocrine gland is most likely over-producing its hormone?

1. thyroid gland
2. adrenal cortex
3. adrenal medulla
4. parathyroid gland
5. pancreas [top] [50] [100]

110-119

110. In the patient described in question #7, What hormone is most likely over released
     1. Thyroid hormone
     2. Calcitonin
     3. Epinephrine
     4. Aldosterone
     5. Parathyroid hormone [top]

111. A young boy visits the local doctor with a list of peculiar symptoms: abnormally tall for his age and family background, nervous and easily excited, very warm, always hungry, and very thin. What hormone is most likely over-produced?
     1. Thyroid hormone
     2. Calcitonin
     3. Epinephrine
     4. Aldosterone
     5. Parathyroid hormone [top]

112. A young woman visits the local doctor complaining about the appearance of facial hair, acne, and a slight deepening of her voice. Later she is diagnosed as having a tumor. Which gland would you predict was involved?
     1. thyroid
     2. adrenal cortex
     3. adrenal medulla
     4. parathyroid
     5. pancreas [top]

113. A man goes to see his doctor complaining of weight gain, even though he has been careful with what he eats. The doctor determines he has high blood pressure, high blood sodium levels and low blood potassium levels. Over-production of which hormone would explain his symptoms?
     1. Cortisol
     2. Insulin
     3. Glucagon
     4. Aldosterone
     5. Calcitonin [top]

Match the following.

120-129

120. Virtually all types of nonsteroid hormones have receptors located on the surface membrane of cells and exert their effects through intracellular:
     1. ions
     2. second messengers
     3. nucleotides
     4. amino acids [top]

121. Which of the following would be most associated with the action of steroid hormones on cells?
     1. Extracellular receptors with a specificity for only a single amino acid sequence on the hormone.
     2. An enzyme that catalyzes the formation of cyclic AMP.
     3. A hormone-receptor complex that interacts directly with the cell’s DNA.
     4. G-protein second messenger systems [top]

Match the following.

127. Which of the following is a change that may be caused by a hormonal stimulus?
     1. a change in the membrane potential
     2. the stimulation of a genetic event resulting in protein synthesis
     3. an increase in enzymatic activity
     4. a and c are both correct
     5. all of the above [top]

128. The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on:
     1. the location of the tissues or organ with respect to the circulatory path.
     2. the membrane potential of the cells of the target organ.
     3. the presence of the appropriate receptors on/in the cells of the target tissue or organ.
     4. all hormones of the human body are able to stimulate any and all cell types because hormones are powerful and nonspecific.
     5. a and b are both correct. [top]

129. One of the least complicated of the endocrine control systems directly responds to changing blood levels of ions and nutrients. Examples include increased blood levels of calcium, glucose and potassium. Which of the following describes this mechanism?
     1. humoral stimulation
     2. neural stimulation
     3. protein synthesis
     4. hormonal stimulation [top] [50] [100] [120]