Adrenal medulla and catecholamines — MCQs

A previously healthy 61-year-old man comes to the physician because of a 6-month history of morning headaches. He also has fatigue and trouble concentrating on his daily tasks at work. He sleeps for 8 hours every night; his wife reports that he sometimes stops breathing for a few seconds while sleeping. His pulse is 71/min and blood pressure is 158/96 mm Hg. He is 178 cm (5 ft 10 in) tall and weighs 100 kg (220 lb); BMI is 31.6 kg/m2 . Which of the following is the most likely cause of this patient's hypertension?

A drug research team has synthesized a novel oral drug that acts as an agonist at multiple adrenergic receptors. When administered in animals, it has been shown to produce urinary retention at therapeutic doses with the absence of other manifestations of adrenergic stimulation. The researchers are interested in understanding signal transduction and molecular mechanisms behind the action of the novel drug. Which of the following receptors would most likely transduce signals across the plasma membrane following the administration of this novel drug?

A 65-year-old male with a history of CHF presents to the emergency room with shortness of breath, lower leg edema, and fatigue. He is diagnosed with acute decompensated congestive heart failure, was admitted to the CCU, and treated with a medication that targets beta-1 adrenergic receptors preferentially over beta-2 adrenergic receptors. The prescribing physician explained that this medication would only be used temporarily as its efficacy decreases within 2-3 days due to receptor downregulation. Which of the following was prescribed?

A 25-year-old man presents to the emergency department with a severe pulsatile headache for an hour. He says that he is having palpitations as well. He adds that he has had several episodes of headache in the past which resolved without seeking medical attention. He is a non-smoker and does not drink alcohol. He denies use of any illicit drugs. He looks scared and anxious. His temperature is 37°C (98.6°F), respirations are 25/min, pulse is 107/min, and blood pressure is 221/161 mm Hg. An urgent urinalysis reveals elevated plasma metanephrines. What is the next best step in the management of this patient?

A 20-year-old man is brought to the emergency room for evaluation of a back injury sustained while at work. A CT scan of the lumbar spine shows an incidental 2-cm mass adjacent to the inferior vena cava. Histologic examination of a biopsy specimen of the mass shows clusters of chromaffin cells. This mass is most likely to secrete which of the following substances?

An investigator is studying the mechanism regulating pigment production in the skin. She has isolated a hormone produced by the anterior and intermediate lobe of the pituitary gland that stimulates neural crest-derived cells to produce pigments through the oxidation and polymerization of the amino acid tyrosine. This hormone is most likely cosecreted with a substance that acts on which of the following receptors?

An endocrine surgeon wants to evaluate the risk of multiple endocrine neoplasia (MEN) type 2 syndromes in patients who experienced surgical hypertension during pheochromocytoma resection. She conducts a case-control study that identifies patients who experienced surgical hypertension and subsequently compares them to the control group with regard to the number of patients with underlying MEN type 2 syndromes. The odds ratio of MEN type 2 syndromes in patients with surgical hypertension during pheochromocytoma removal was 3.4 (p < 0.01). Given the rare disease assumption, this odds ratio can be interpreted as an approximation of the relative risk. The surgeon concludes that the risk of surgical hypertension during pheochromocytoma removal is 3.4 times greater in patients with MEN type 2 syndromes than in patients without MEN syndromes. This conclusion is best supported by which of the following assumptions?

An investigator is studying the principles of cell-to-cell signaling of the autonomic nervous system. It is found that the adrenal medulla has receptors that, when activated, result in the immediate opening of Na+, Ca2+, and K+ channels, which subsequently leads to the secretion of epinephrine and norepinephrine. These receptors are structurally most similar to which of the following receptors?

A 9-year-old girl is admitted to the hospital with a one-day history of acute abdominal pain and vomiting. She also has a two-day history of fever, headache, and neck pain. Her immunizations are up-to-date. She is confused and oriented only to place and person. Her temperature is 39.7°C (103.5°F), pulse is 148/min, blood pressure is 90/50 mm Hg, and respiratory rate is 28/min. Cervical range of motion is limited by pain. The remainder of the neurologic examination shows no abnormalities. Laboratory studies show: Hemoglobin 10.9 g/dL Leukocyte count 44,000/mm3 Serum pH 7.33 Na+ 130 mEq/L Cl- 108 mEq/L K+ 6.1 mEq/L HCO3- 20 mEq/L Urea nitrogen 34 mg/dL Glucose 180 mg/dL Creatinine 2.4 mg/dL Urine ketones negative A CT scan of the head shows enhancement of the arachnoid and pia mater. Cerebrospinal fluid analysis shows a leukocyte count of 3,400/μL (90% neutrophils), a glucose concentration of 50 mg/dL, protein concentration of 81 mg/dL, and no erythrocytes. Gram stain of the CSF shows gram-negative diplococci. This patient is at increased risk for which of the following complications?

A 14-year-old girl presents with her mother to a physician's office. They are both concerned with the amount of hair growing on the girl's upper lip and cheeks. There are also sparse hairs on her chest. The mother reports that her daughter has not started menstruating either. The girl was born at 39 weeks gestation via spontaneous vaginal delivery. She is up to date on all vaccines and is meeting all developmental milestones. On examination, the patient is in the 55th percentile for her height. Her blood pressure is 90/50 mm Hg, pulse is 75/min, and respirations are 15/min. There is thin dark hair on her upper lip and on her cheeks. She also has pustular acne on her face and shoulders. Her breasts are in the initial stages of development and she speaks with a deep voice describing her concerns to the physician. Based on her clinical history, which of the following enzymes are most likely deficient?