Endo Hypthal Pitu Phys Pharm MCQ's
Questions and Answers
- 1.
A 23-year old male patient comes to your office who is 3 feet 6 inches tall. your initial diagnosis is that an endocrine disorder accounts for his short stature. To confirm your diagnosis you run a series of laboratory tests. The laboratory results come back with the following findings: 1) plasmaIGF-1levels are extremely low, 2) plasma GH levels are very high, and 3) exogenous GHRH elicits a further increase in GH. What would be the most likely defect in this individual to explain his dwarfism?
- A.
Excessive production of somatostat in by periventricular hypothalamic neurons.
- B.
Inadequate production of GHRH by arcuate neurons of the hypothalamus
- C.
Inadequate production of IGF-1 by somatotrophs of the anterior pituitary gland.
- D.
Overproduction of GHRH by arcuate neurons of the hypothalamus.
- E.
Inability of the liver to produce IGF-1.
Correct Answer
E. Inability of the liver to produce IGF-1.Explanation
The most likely defect in this individual to explain his dwarfism is the inability of the liver to produce IGF-1. This is supported by the extremely low plasma IGF-1 levels found in the laboratory tests. IGF-1 is a hormone that is stimulated by GH and is responsible for the growth-promoting effects of GH. In this case, the high plasma GH levels indicate that GH production is not the issue, but rather the liver's inability to produce IGF-1 is preventing the growth-promoting effects of GH.Rate this question:
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- 2.
Both the anterior and posterior pituitary glands depend upon input from hypothalamic nuclei for release of pituitary hormones. In the following table which row correctly lists the type of connections between the hypothalamus and the anterior and posterior pituitary glands? . Hypothalamus to anterior pituitary Hypothalamus to posterior pituitary A Axonal connections Axonal connections B Releasing factors Releasing factors C Axonal connections Releasing factors D Releasing factors Axonal connections
- A.
A
- B.
B
- C.
C
- D.
D
Correct Answer
D. DExplanation
The correct answer is D. The explanation is that the hypothalamus releases releasing factors that travel through the bloodstream to the anterior pituitary gland, where they stimulate the release of specific hormones. This is known as the hypothalamic-pituitary portal system. On the other hand, the hypothalamus directly sends axonal connections to the posterior pituitary gland, allowing it to release hormones such as oxytocin and vasopressin. Therefore, D correctly lists the type of connections between the hypothalamus and the anterior and posterior pituitary glands.Rate this question:
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- 3.
While doing a pediatric rotation, you observe a visit by 10-year-old male patient who is below the 1Oth percentile for height. The pediatrician makes an initial diagnosis of dwarfism caused by pituitary dysfunction. However, the physician asks you to develop a strategy to determine if the actual cause is growth hormone receptor dysfunction. Laboratory values for serum growth hormone were above normal. Which of the following would constitute a key piece of information in your diagnostic strategy?
- A.
Low plasma levels of growth hormone binding protein
- B.
Low plasma levels of IGF-1
- C.
Elevated plasma levels for growth hormone releasing hormone
- D.
Decreased plasma levels of somatostatin
Correct Answer
A. Low plasma levels of growth hormone binding proteinExplanation
A key piece of information in the diagnostic strategy would be low plasma levels of growth hormone binding protein. Growth hormone binding protein (GHBP) is responsible for binding to growth hormone and prolonging its half-life in the bloodstream. If there are low levels of GHBP, it suggests that there is a dysfunction in the binding of growth hormone, which could be caused by growth hormone receptor dysfunction. This information would support the hypothesis that the patient's dwarfism is caused by growth hormone receptor dysfunction rather than pituitary dysfunction.Rate this question:
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- 4.
Although the production of IGF-1 by the liver makes an important contribution to circulating levels of IGF-1,many other tissues produce IGFs. For most tissues,IGF-1 is considered to act as what type of signaling factor?
- A.
Hormone
- B.
Paracrine
- C.
Autocrine
- D.
Intracrine
- E.
Neuroendocrine
Correct Answer
B. ParacrineExplanation
IGF-1 is considered to act as a paracrine signaling factor in most tissues. Paracrine signaling occurs when a cell secretes a signal molecule that acts on nearby cells, influencing their behavior or function. In the case of IGF-1, it is produced by various tissues and acts on neighboring cells to regulate processes such as cell growth, proliferation, and differentiation. This localized signaling allows for precise control and coordination of cellular activities within a specific tissue or organ.Rate this question:
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- 5.
A 25-year-old male patient comes to a local clinic with the following complaints. He has to urinate frequently and he is constantly drinking water. A 24-urine collection is taken with the following findings. Urine volume is 6 liters per day and the specific gravity of the urine is 1.005 (normal range is 1.010-1.025j.ysur te_ntative diagnosis is diabetes insipidus. You administer intravenously an analogue of vasopressin and observe that the subsequent 24 hour urine collection is reduced to 3 liters per day. What is the most likely explanation for his polyuria?
- A.
Aquatrophs of the anterior pituitary are not being stimulated by vasopressin releasing hormone.
- B.
V1 receptors on epithelial cells of the collecting tubules and ducts are absent.
- C.
V2 receptors on epithelial cells of the collecting
- D.
High plasma concentration of vasopressin acting at magnocellular neurons of the Para ventricular nucleus of the hypothalamus has suppressed hypothalamic release of vasopressin
- E.
Magnocellular neurons of the Para ventricular and suproptic nuclei of the hypothalamus are not responding to an increase in whole body osmolarity and are not releasing vasopressin from the posterior pituitary.
Correct Answer
E. Magnocellular neurons of the Para ventricular and suproptic nuclei of the hypothalamus are not responding to an increase in whole body osmolarity and are not releasing vasopressin from the posterior pituitary.Explanation
The most likely explanation for the patient's polyuria is that the magnocellular neurons of the Para ventricular and suproptic nuclei of the hypothalamus are not responding to an increase in whole body osmolarity and are not releasing vasopressin from the posterior pituitary. Vasopressin, also known as antidiuretic hormone (ADH), is responsible for regulating water balance in the body by controlling the reabsorption of water in the kidneys. In this case, the lack of response from the hypothalamus leads to a decrease in vasopressin release, resulting in excessive urine production and polyuria.Rate this question:
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- 6.
Which drug for treating acromegaly acts by blocking receptors for growth hormone?
- A.
Somatropin
- B.
Pegvisomant
- C.
Octreotide
- D.
Sermorelin
- E.
Cabergoline
Correct Answer
B. PegvisomantExplanation
Pegvisomant is the correct answer because it acts by blocking receptors for growth hormone. This drug is used for treating acromegaly, a condition characterized by excessive growth hormone production. By blocking the growth hormone receptors, pegvisomant helps to reduce the effects of the excess hormone in the body. It does not stimulate the production or release of growth hormone, but instead directly inhibits its action.Rate this question:
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- 7.
By which of the following mechanisms does bromocriptine relieve symptoms of hyperprolactinemia in a patient with prolactin-secreting pituitary adenoma?
- A.
Blocking prolactin receptors
- B.
Blocking receptors for prolactin releasing hormone
- C.
A cytotoxic effect on pituitary adenoma cells
- D.
Stimulating dopamine receptors
- E.
Stimulating serotonin receptors
Correct Answer
D. Stimulating dopamine receptorsExplanation
Bromocriptine relieves symptoms of hyperprolactinemia in a patient with prolactin-secreting pituitary adenoma by stimulating dopamine receptors. This medication is a dopamine agonist, which means it binds to and activates dopamine receptors in the brain. By stimulating these receptors, bromocriptine inhibits the release of prolactin from the pituitary gland, thereby reducing the levels of this hormone in the body. This helps alleviate the symptoms associated with hyperprolactinemia, such as irregular menstrual periods, infertility, and breast milk production in non-pregnant women.Rate this question:
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- 8.
A 3O-year-old man who suffered a head injury presented one month after recovery with excessive thirst and urination. After examination and lab tests he was diagnosed with neurogenic diabetes insipidus. Desmopressin was prescribed to him. Which of the following is its mechanism of action?
- A.
It stimulatesV2 receptors
- B.
It prevents the breakdown of ADH
- C.
It stimulate the release of ADH from posterior pituitary
- D.
It stimulates V1 receptors
Correct Answer
A. It stimulatesV2 receptorsExplanation
Desmopressin is a synthetic form of vasopressin, also known as antidiuretic hormone (ADH). It acts by stimulating V2 receptors in the renal collecting ducts, which leads to increased reabsorption of water and reduced urine production. This helps to alleviate the symptoms of excessive thirst and urination in patients with neurogenic diabetes insipidus.Rate this question:
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- 9.
A 35-year-old man presented to the hospital with a history of joint pain, headache, excessive sweating, and deepening of the voice. A physical examination revealed protrusion of the jaw, enlargement of the hands, thickening of the skin, and a barrel chest. A CT scan disclosed a pituitary adenoma and the patient underwent radiotherapy. Which of the following drugs was most likely prescribed while waiting for radiotherapy to work?
- A.
Leuprolide
- B.
Cosyntropin
- C.
Somatropin
- D.
Octreotide
- E.
Protirelin
Correct Answer
D. OctreotideExplanation
Octreotide is a synthetic analogue of somatostatin, a hormone that inhibits the release of growth hormone. The patient's symptoms, such as joint pain, headache, excessive sweating, deepening of the voice, protrusion of the jaw, enlargement of the hands, thickening of the skin, and a barrel chest, are consistent with acromegaly, which is caused by excessive growth hormone secretion. The presence of a pituitary adenoma further supports this diagnosis. Octreotide would be prescribed to help control the symptoms of acromegaly while waiting for radiotherapy to work on reducing the size of the adenoma and decreasing growth hormone secretion.Rate this question:
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- 10.
A 35-year-old woman presented to the clinic complaining of continuous thirst and polyuria. She had had a basal skull fracture following a car accident six month previously from which she recovered completely. She reported that she often awoke at night because of thirst and a need to urinate. Urinalysis showed a urine osmolality of 2O mOsm/Kg and undetectable plasma ADH levels. Which if the following drugs would be appropriate for the patient?
- A.
Hydrochlorothiazide
- B.
Amiloride
- C.
Desmopressin
- D.
Carbamazepine
- E.
Chlorpropamide
Correct Answer
C. DesmopressinExplanation
The patient's symptoms of continuous thirst and polyuria, along with undetectable plasma ADH levels and low urine osmolality, suggest a diagnosis of central diabetes insipidus. Desmopressin is a synthetic form of ADH and would be appropriate for this patient to replace the deficient hormone and alleviate her symptoms. Hydrochlorothiazide, Amiloride, Carbamazepine, and Chlorpropamide are not indicated for central diabetes insipidus.Rate this question:
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- 11.
The presence of a tumor in the anterior pituitary causes a decrease in ACTH secretion. Which of the following correctly describes changes in plasma levels of hormones?
- A.
Increased CRH, increased ACTH, and increased cortisol
- B.
Decreased CRH, decreased ACTH, and decreased cortisol
- C.
Increased CRH, decreased ACTH, and decreased cortisol
- D.
Increased CRH, increased ACTH, and decreased cortisol
- E.
Decreased CRH, decreased ACTH, and increased cortisol
Correct Answer
C. Increased CRH, decreased ACTH, and decreased cortisolExplanation
When a tumor is present in the anterior pituitary, it can disrupt the normal secretion of hormones. In this case, the tumor causes a decrease in ACTH secretion. ACTH is responsible for stimulating the release of cortisol from the adrenal glands. Therefore, with decreased ACTH levels, there will be a decrease in cortisol secretion. However, the tumor can also lead to an increase in the production of CRH (corticotropin-releasing hormone) by the hypothalamus, which stimulates the release of ACTH. Therefore, the plasma levels of hormones in this scenario would be increased CRH, decreased ACTH, and decreased cortisol.Rate this question:
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- 12.
A 48 YO man with a family history of heart disease has followed a heart-healthy lifestyle for fifteen years. Despite these efforts he has recently experienced unusual fatigue and lightheadedness , especially when rising suddenly. Physical examination, demonstrates postural hypotension and a darker-than usual complexion for midwinter in the Midwest (he works and exercises indoors). Lab work reveals that he is hyponatremic, . hyperkalemic, and hypocalcemic Further blood tests are ordered to assay plasma corticotropin-releasing hormone(CRH), corticotropin (ACTH), and cortisol. What combination of hyper and/or hyposecretion for these hormones would be the most likely given this man's signs and symptoms? . CRH secretion ACTH secretion Cortisol secretion A Hyper-secretion Hyper-secretion Hyper-secretion B Hyper-secretion Hyper-secretion Hypo-secretion C Hyper-secretion Hypo-secretion Hypo-secretion D Hypo-secretion Hypo-secretion Hypo-secretion E Hypo-secretion Hypo-secretion hyper-secretion
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
B. BExplanation
Given the man's signs and symptoms of postural hypotension, unusual fatigue, lightheadedness, darker-than-usual complexion, and hyponatremia, hyperkalemia, and hypocalcemia, it is likely that there is a dysfunction in the adrenal glands. The adrenal glands are responsible for the production of cortisol, which helps regulate blood pressure and electrolyte balance. In this case, the most likely combination of hormone secretion would be hypersecretion of CRH, hypersecretion of ACTH, and hyposecretion of cortisol. Hypersecretion of CRH and ACTH would lead to increased stimulation of the adrenal glands, resulting in increased production of cortisol. However, the hyposecretion of cortisol would lead to the symptoms observed in the patient.Rate this question:
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- 13.
A 19 YO man decides to begin a vegan diet, but he fails to adequately compensate for the nutritional content of the dairy products in his former diet, so his intake of calcium drops dramatically. Which of the following hormones' direct actions will be most important in the maintenance of his plasma calcium?
- A.
Insulin
- B.
Thyroid hormone
- C.
Calcitonin
- D.
1,25-dihyroxycholecalciferol
- E.
Parathyroid hormone
Correct Answer
D. 1,25-dihyroxycholecalciferolExplanation
When the man fails to adequately compensate for the nutritional content of dairy products in his former diet, his intake of calcium drops dramatically. The hormone 1,25-dihyroxycholecalciferol, also known as active vitamin D, plays a crucial role in maintaining plasma calcium levels. It promotes the absorption of calcium from the intestines and reabsorption of calcium from the kidneys, ensuring that enough calcium is available in the bloodstream. Therefore, in this situation, the direct actions of 1,25-dihyroxycholecalciferol are most important in maintaining his plasma calcium levels.Rate this question:
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- 14.
A 28 year-old woman attends her doctor because she has not had a menstrual cycle of two months, but commercial pregnancy tests have proven negative. She reports that a few weeks before her expected menstrual cycle was missed, she had suffered an accident in a gaffe, in which she had fallen from a climbing rope" head first" onto some weight-training equipment, and sustained bruising on the left side of her face around her cheek, eye and temples. The woman reports that following the accident she had noticed that she was feeling continually fatigued, and had gained weight. She feels thirsty most of the time and is perplexed as to why she needs to urinate more often than before. Physical examination confirms that the woman is not. pregnant and reveals traces of a white crystalline deposit around her nipples. The level of which hormone would be expected to be elevated in the plasma of this patient?
- A.
Luteinizing Hormone (LH)
- B.
Thyroid Stimulating Hormone (TSH)
- C.
Follicle Stimulating Hormone (FSH)
- D.
Oxytocin
- E.
Prolactin (Prl)
Correct Answer
E. Prolactin (Prl)Explanation
The correct answer is Prolactin (Prl). Prolactin is a hormone produced by the pituitary gland that is responsible for stimulating milk production in the breasts. In this case, the woman's symptoms, such as the absence of menstrual cycle, weight gain, fatigue, and the presence of a white crystalline deposit around her nipples, suggest that she may be experiencing hyperprolactinemia, which is an elevated level of prolactin in the blood. This condition can be caused by head trauma, such as the accident she experienced, and can lead to disruptions in the menstrual cycle and other symptoms described.Rate this question:
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Mar 22, 2023Quiz Edited by
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Feb 14, 2012Quiz Created by
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