Endocrine system (thyroid, adrenal, pancreas)

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 1: A scientist in Chicago is studying a new blood test to detect Ab to EBV with increased sensitivity and specificity. So far, her best attempt at creating such an exam reached 82% sensitivity and 88% specificity. She is hoping to increase these numbers by at least 2 percent for each value. After several years of work, she believes that she has actually managed to reach a sensitivity and specificity much greater than what she had originally hoped for. She travels to China to begin testing her newest blood test. She finds 2,000 patients who are willing to participate in her study. Of the 2,000 patients, 1,200 of them are known to be infected with EBV. The scientist tests these 1,200 patients' blood and finds that only 120 of them tested negative with her new exam. Of the patients who are known to be EBV-free, only 20 of them tested positive. Given these results, which of the following correlates with the exam's specificity?

• A. 82%
• B. 90%
• C. 84%
• D. 86%
• E. 98% (Correct Answer)

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***98%*** - **Specificity** measures the proportion of **true negatives** among all actual negatives. - In this case, 800 patients are known to be EBV-free (actual negatives), and 20 of them tested positive (false positives). This means 800 - 20 = 780 tested negative (true negatives). Specificity = (780 / 800) * 100% = **98%**. *82%* - This value represents the *original sensitivity* before the scientist’s new attempts to improve the test. - It does not reflect the *newly calculated specificity* based on the provided data. *90%* - This value represents the *newly calculated sensitivity* of the test, not the specificity. - Out of 1200 EBV-infected patients, 120 tested negative (false negatives), meaning 1080 tested positive (true positives). Sensitivity = (1080 / 1200) * 100% = 90%. *84%* - This percentage is not directly derived from the information given for either sensitivity or specificity after the new test results. - It does not correspond to any of the calculated values for the new test's performance. *86%* - This percentage is not directly derived from the information given for either sensitivity or specificity after the new test results. - It does not correspond to any of the calculated values for the new test's performance.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 2: A 42-year-old man who is employed as a construction worker presents to his primary care physician with complaints of moderate headaches and profuse sweating. He reports the need to carry up to 3 additional shirt changes to work because they drench quickly even with tasks of low physical exertion. His coworkers have commented about his changing glove and boot sizes, which have increased at least 4 times since he joined the company 10 years ago. Physical examination is unremarkable except for blood pressure of 160/95 mm Hg, hyperhidrosis, noticeably large pores, hypertrichosis, widely spaced teeth, and prognathism. Which of the following best explains the patient’s clinical manifestations?

• A. Increased serum cortisol
• B. Increased thyroid-stimulating hormone
• C. Increased serum metanephrines
• D. Increased serum insulin-like growth factor 1 (IGF-1) (Correct Answer)
• E. Increased serum testosterone

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***Increased serum insulin-like growth factor 1 (IGF-1)*** - Elevated **IGF-1** levels are indicative of **acromegaly**, a condition caused by excess growth hormone (GH) secretion, which explains the gradual changes in glove and boot sizes, prognathism, widely spaced teeth, and large pores. - The symptoms of **profuse sweating**, **hypertrichosis**, **headaches**, and **hypertension** are common clinical manifestations of acromegaly due to the systemic effects of chronic GH excess. *Increased serum cortisol* - **Increased cortisol** (Cushing's syndrome) would present with central obesity, moon facies, buffalo hump, and striae, which are not described in the patient. - While hypertension and hyperhidrosis can occur in Cushing's, the characteristic physical changes related to growth are absent. *Increased thyroid-stimulating hormone* - Elevated **TSH** suggests **hypothyroidism**, which would typically cause fatigue, weight gain, cold intolerance, and bradycardia, rather than profuse sweating and hypertension. - **Hyperthyroidism** (low TSH, high thyroid hormones) can cause sweating and hypertension, but it would not explain the gradual increase in body and appendage size. *Increased serum metanephrines* - Elevated **metanephrines** are a hallmark of **pheochromocytoma**, which typically presents with paroxysmal episodes of hypertension, palpitations, and sweating. - While sweating and hypertension are present, the absence of episodic symptoms and the long-term changes in body size make pheochromocytoma less likely. *Increased serum testosterone* - **Increased testosterone** in a male would typically lead to increased muscle mass, acne, and potentially male-pattern baldness, but not the specific skeletal and soft tissue growth patterns observed, such as increased shoe and glove size or prognathism. - While some skin changes might occur, **hyperhidrosis** and the dramatic facial and extremity changes are not characteristic features of testosterone excess.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 3: A 15-year-old female presents to her family physician for an annual school physical exam and check-up. She is accompanied by her mother to the visit and is present in the exam room. The patient has no complaints, and she does not have any past medical problems. She takes no medications. The patient reports that she remains active, exercising 5 times a week, and eats a healthy and varied diet. Which of the following would be the best way for the physician to obtain a more in-depth social history, including sexual history and use of alcohol, tobacco, or recreational drugs?

• A. Disallow the mother to be present in the examination room throughout the entirety of the visit
• B. Give the patient a social history questionnaire to fill out in the exam room
• C. Ask the mother to step outside into the hall for a portion of the visit (Correct Answer)
• D. Ask the patient the questions directly, with her mother still in the exam room
• E. Speak softly to the patient so that the mother does not hear and the patient is not embarrassed

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***Ask the mother to step outside into the hall for a portion of the visit*** - This approach allows the physician to speak with the adolescent **privately and confidentially**, which is crucial for obtaining sensitive information such as sexual history, drug use, and mental health concerns. - Adolescents are more likely to disclose personal information when their parents are not present, fostering trust and ensuring **comprehensive history-taking** vital for their well-being. *Disallow the mother to be present in the examination room throughout the entirety of the visit* - This is an **overly restrictive** approach that might create tension or distrust between the physician, patient, and parent, especially at the start of the visit. - While privacy is essential for sensitive topics, parental presence can be valuable for discussing general health, family history, and **treatment plans**, especially for younger adolescents. *Give the patient a social history questionnaire to fill out in the exam room* - While questionnaires can be useful for gathering basic information, they often **lack the nuance** of a direct conversation and may not prompt the patient to elaborate on sensitive issues. - Furthermore, having the mother present while the patient fills out a questionnaire on sensitive topics still **compromises confidentiality** and may lead to incomplete or dishonest answers. *Ask the patient the questions directly, with her mother still in the exam room* - Asking sensitive questions with a parent present is **unlikely to yield truthful and complete answers**, as adolescents may feel embarrassed, judged, or fear parental disapproval. - This approach compromises the **confidentiality** that is fundamental to building trust with adolescent patients. *Speak softly to the patient so that the mother does not hear and the patient is not embarrassed* - Speaking softly is **unprofessional** and still does not guarantee privacy, as the mother might still overhear parts of the conversation. - This method also **fails to establish true confidentiality**, which is central to building rapport and encouraging open communication with adolescent patients about sensitive topics.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 4: A 60-year-old man comes to the emergency department because of recurrent episodes of fatigue, palpitations, nausea, and diaphoresis over the past 6 months. The episodes have become more frequent in the last 2 weeks and he has missed work several times because of them. His symptoms usually improve after he drinks some juice and rests. He has had a 2-kg (4.5-lb) weight gain in the past 6 months. He has a history of bipolar disorder, hypertension, and asthma. His sister has type 2 diabetes mellitus and his mother has a history of medullary thyroid carcinoma. His medications include lithium, hydrochlorothiazide, aspirin, and a budesonide inhaler. His temperature is 36.3°C (97.3°F), pulse is 92/min and regular, respirations are 20/min, and blood pressure is 118/65 mm Hg. Abdominal examination shows no abnormalities. Serum studies show: Na+ 145 mEq/L K+ 3.9 mEq/L Cl- 103 mEq/L Calcium 9.2 mg/dL Glucose 88 mg/dL Which of the following is the most appropriate next step in diagnosis?

• A. Corticotropin stimulation test
• B. Water deprivation test
• C. Oral glucose tolerance test
• D. 24-hour urine catecholamine test
• E. 72-hour fasting test (Correct Answer)

Endocrine system (thyroid, adrenal, pancreas) Explanation: **72-hour fasting test** - The patient's symptoms (fatigue, palpitations, nausea, diaphoresis) that improve with eating (drinking juice) are highly suggestive of **hypoglycemia**, fitting **Whipple's triad**. - A 72-hour fasting test is the gold standard for diagnosing **insulinoma**, a neuroendocrine tumor that causes endogenous hyperinsulinism and recurrent hypoglycemia. *Corticotropin stimulation test* - This test is used to diagnose **adrenal insufficiency** by evaluating the adrenal glands' response to ACTH. - The patient's symptoms are inconsistent with adrenal insufficiency, and his blood pressure is stable, arguing against a hypotensive crisis. *Water deprivation test* - This test is used to diagnose **diabetes insipidus** by assessing the kidney's ability to concentrate urine. - The patient's symptoms do not align with polyuria and polydipsia characteristic of diabetes insipidus. *Oral glucose tolerance test* - This test is primarily used to diagnose **diabetes mellitus** or impaired glucose tolerance. - While helpful for assessing glucose metabolism, it is not the initial test for recurrent symptomatic hypoglycemia that improves with sugar intake. *24-hour urine catecholamine test* - This test is used to diagnose **pheochromocytoma**, a tumor that causes excessive catecholamine release. - While palpitations and diaphoresis can occur, the improvement with glucose and lack of sustained hypertension make pheochromocytoma less likely.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 5: An investigator is studying a drug that acts on the thyroid hormone pathway. Levels of serum free T3 and T4 in healthy participants are measured before and after administration of the drug. After administration, there is a decrease in the average serum free T3 level, while the average serum free T4 level is increased compared to initial serum studies. Inhibition of which of the following is the most likely mechanism of action of this drug?

• A. Thyroid-stimulating hormone
• B. Follicular iodotyrosine deiodinase
• C. Follicular thyroid peroxidase
• D. Peripheral 5'-deiodinase (Correct Answer)
• E. Follicular thyroid proteases

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***Peripheral 5'-deiodinase*** - Inhibition of **peripheral 5'-deiodinase** would decrease the conversion of **T4 to T3** in the periphery, resulting in lower **free T3** and higher **free T4** levels. - This enzyme is crucial for activating T4 into the more potent T3, and its blockade explains the observed changes in hormone levels. *Thyroid-stimulating hormone* - Inhibition of **TSH** would lead to a decrease in the production and release of both **T3 and T4** from the thyroid gland. - This contradicts the observed increase in **free T4** levels. *Follicular iodotyrosine deiodinase* - This enzyme is involved in recycling iodine from **monoiodotyrosine (MIT)** and **diiodotyrosine (DIT)** within the thyroid follicular cells, which is important for efficient thyroid hormone synthesis. - Its inhibition would primarily affect iodine availability and synthesis, not directly lead to increased T4 and decreased T3 in the periphery. *Follicular thyroid peroxidase* - **Thyroid peroxidase (TPO)** is critical for the **iodination of tyrosine residues** on thyroglobulin and the **coupling of MIT and DIT** to form T3 and T4. - Inhibition of TPO would decrease the synthesis of both **T3 and T4**, contrary to the observed increase in **free T4**. *Follicular thyroid proteases* - **Thyroid proteases** cleave thyroglobulin to release mature **T3 and T4** into the bloodstream. - Inhibition of these proteases would lead to a decrease in the release of both **T3 and T4**, which does not align with the observed increase in **free T4**.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 6: A 40-year-old woman visits her physician’s office with her husband. Her husband says that she has been complaining of recurring headaches over the past few months. A year ago she was diagnosed with diabetes and is currently on treatment for it. About 6 months ago, she was diagnosed with high blood pressure and is also taking medication for it. Her husband is concerned about the short span during which she has been getting all these symptoms. He also says that she occasionally complains of changes and blurring in her vision. In addition to all these complaints, he has observed changes in her appearance, more prominently her face. Her forehead and chin seem to be protruding more than usual. Suspecting a hormonal imbalance, which of the following initial tests would the physician order to indicate a possible diagnosis?

• A. Chest X-ray
• B. Pituitary magnetic resonance image (MRI)
• C. Serum growth hormone
• D. Glucose suppression test
• E. Serum insulin-like growth factor-1 (IGF-1) (Correct Answer)

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***Serum insulin-like growth factor-1 (IGF-1)*** - Elevated **serum IGF-1 levels** are the most sensitive and reliable initial screening test for **acromegaly**, reflecting sustained growth hormone excess. - The clinical presentation with **new-onset diabetes**, **hypertension**, **headaches**, **visual changes**, and **facial prognathism** strongly suggests acromegaly, a condition caused by excessive growth hormone (GH) secretion. *Chest X-ray* - A chest X-ray is primarily used to evaluate **pulmonary or cardiac conditions** and would not directly screen for hormonal imbalances like acromegaly. - While acromegaly can lead to **cardiomegaly** or **sleep apnea**, a chest X-ray is not the initial diagnostic test for growth hormone excess itself. *Pituitary magnetic resonance image (MRI)* - A **pituitary MRI** is the imaging study of choice to confirm the presence of a **pituitary adenoma** after biochemical confirmation of acromegaly, not an initial screening test. - It visualizes the pituitary gland and helps locate the tumor but is ordered *after* biochemical tests indicate GH excess. *Serum growth hormone* - A single random **serum growth hormone (GH) level** can be misleading because GH secretion is pulsatile, making a single measurement unreliable for diagnosing acromegaly. - While acromegaly involves elevated GH, a random sample is not the optimal initial diagnostic test due to its **fluctuating levels**. *Glucose suppression test* - The **oral glucose tolerance test (OGTT)** with GH measurement is the confirmatory test for acromegaly, used to demonstrate **failure of GH suppression** after glucose load. - This is a diagnostic procedure performed *after* an elevated IGF-1 level suggests acromegaly, not an initial screening test.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 7: A 43-year-old woman comes to the physician for an annual health maintenance examination. On questioning, she has had fatigue and headaches for the last month. A few weeks ago, she had to have her wedding ring resized because it had become too small for her finger. She has mild persistent asthma and anxiety disorder. She drinks 2–3 glasses of red wine per night and has smoked one pack of cigarettes daily for 16 years. She works a desk job in accounting and has recently been working long hours due to an upcoming company merger. Her father has a history of a pituitary adenoma. Current medications include alprazolam, a fluticasone inhaler, and an albuterol inhaler. She is 160 cm (5 ft 3 in) tall and weighs 81.6 kg (180 lb); her BMI is 32 kg/m2. Her temperature is 37.2°C (99°F), pulse is 92/min, and blood pressure is 132/80 mm Hg. Examination shows no abnormalities. Fasting laboratory studies show: Hemoglobin 13 g/dL Serum Na+ 135 mEq/L K+ 4.6 mEq/L Cl- 105 mEq/L HCO3- 22 mEq/L Urea nitrogen 17 mg/dL Glucose 160 mg/dL Creatinine 0.9 mg/dL Which of the following is the most likely underlying mechanism of this patient's hyperglycemia?

• A. Decreased insulin production
• B. Adverse effect of medication
• C. Stress
• D. Insulin resistance (Correct Answer)
• E. Hypersecretion of ACTH

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***Insulin resistance*** - The patient's **obesity (BMI 32 kg/m2)**, **sedentary lifestyle**, and **fasting hyperglycemia** (glucose 160 mg/dL) indicate **insulin resistance**, which is the underlying mechanism of hyperglycemia in **type 2 diabetes**. - The **ring resizing due to finger enlargement**, **fatigue**, **headaches**, and **family history of pituitary adenoma** raise suspicion for **acromegaly** (growth hormone excess), which also causes hyperglycemia through **insulin resistance** - growth hormone antagonizes insulin action at peripheral tissues. - Regardless of whether this represents type 2 diabetes or acromegaly, **insulin resistance is the direct mechanism** causing the hyperglycemia in this patient. *Decreased insulin production* - Decreased insulin production is characteristic of **type 1 diabetes** or late-stage type 2 diabetes with beta-cell exhaustion. - The patient's **obesity** and typical metabolic risk factors suggest **insulin resistance** rather than decreased production as the primary mechanism. - No clinical features suggest autoimmune destruction or significant pancreatic damage. *Adverse effect of medication* - The patient's medications (**alprazolam**, **fluticasone inhaler**, **albuterol**) are unlikely to cause significant fasting hyperglycemia. - While high-dose systemic **corticosteroids** can cause hyperglycemia, **inhaled fluticasone** at typical asthma doses has minimal systemic absorption and is not a common cause of sustained hyperglycemia. - **Alprazolam** and **albuterol** do not typically cause hyperglycemia. *Stress* - **Acute stress** can transiently elevate blood glucose through counter-regulatory hormones (cortisol, catecholamines). - However, the **fasting glucose of 160 mg/dL** suggests a chronic metabolic derangement rather than acute stress response alone. - Work-related stress may be a contributing factor but is not the primary underlying mechanism. *Hypersecretion of ACTH* - **ACTH hypersecretion** (Cushing's disease) causes excess cortisol production, leading to hyperglycemia, weight gain, and fatigue. - This patient lacks classic features of Cushing's syndrome: **central obesity with thin extremities**, **moon facies**, **buffalo hump**, **purple striae**, **skin thinning**, or **easy bruising**. - While the patient is obese, the distribution appears generalized rather than the characteristic centripetal pattern of Cushing's syndrome.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 8: Certain glucose transporters that are expressed predominantly on skeletal muscle cells and adipocytes are unique compared to those transporters found on other cell types within the body. Without directly affecting glucose transport in other cell types, which of the following would be most likely to selectively increase glucose uptake in skeletal muscle cells and adipocytes?

• A. Increased plasma glucose concentration
• B. It is physiologically impossible to selectively increase glucose uptake in specific cells
• C. Increased levels of circulating insulin (Correct Answer)
• D. Decreased plasma glucose concentration
• E. Decreased levels of circulating insulin

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***Increased levels of circulating insulin*** - Insulin stimulates the translocation of **GLUT4 transporters** from intracellular vesicles to the cell membrane in **skeletal muscle** and **adipocytes**, thereby increasing glucose uptake. - This mechanism is **selective** because other cell types (e.g., brain, liver) primarily use insulin-independent glucose transporters (e.g., GLUT1, GLUT2, GLUT3) that are constitutively active or respond to different signals. *Increased plasma glucose concentration* - While increased glucose concentration would drive glucose uptake in many cells, it is not **selective** for skeletal muscle and adipocytes since other cells also take up glucose. - Insulin-independent tissues would also increase glucose uptake, making this a non-specific effect. *It is physiologically impossible to selectively increase glucose uptake in specific cells* - This statement is incorrect because the body has mechanisms, such as **insulin-mediated GLUT4 translocation**, that specifically regulate glucose uptake in certain cell types like skeletal muscle and adipocytes. - This regulatory specificity is crucial for maintaining **glucose homeostasis**. *Decreased plasma glucose concentration* - A decrease in plasma glucose would generally **reduce** glucose uptake across all cell types, including skeletal muscle and adipocytes. - It would not selectively increase uptake in any specific cell population. *Decreased levels of circulating insulin* - Decreased insulin levels would lead to **reduced** glucose uptake in insulin-sensitive tissues like skeletal muscle and adipocytes, as GLUT4 transporters would remain sequestered intracellularly. - This would result in higher circulating glucose levels rather than increased uptake.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 9: A 56-year-old male comes to the physician because of a 2-month history of excessive sleepiness. He reports that he has been sleeping for an average of 10 to 12 hours at night and needs to take multiple naps during the day. Six months ago, he was diagnosed with small cell lung carcinoma and underwent prophylactic cranial irradiation. This patient's symptoms are most likely caused by damage to which of the following structures?

• A. Subthalamic nucleus
• B. Ventromedial nucleus
• C. Suprachiasmatic nucleus (Correct Answer)
• D. Preoptic nucleus
• E. Supraoptic nucleus

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***Suprachiasmatic nucleus*** - The **suprachiasmatic nucleus (SCN)** is the primary pacemaker of the **circadian rhythm**, regulating the sleep-wake cycle. Damage to this structure, as from prophylactic cranial irradiation, can lead to disruptions in sleep patterns, such as **excessive daytime sleepiness** and prolonged nocturnal sleep. - The SCN receives input from the **retino-hypothalamic tract** and projects to other hypothalamic nuclei to control the secretion of hormones like **melatonin**, which further regulates sleep. *Subthalamic nucleus* - The **subthalamic nucleus** is a component of the basal ganglia motor circuit and is primarily involved in **motor control**. - Dysfunction of this nucleus is typically associated with **movement disorders** like hemiballismus, not sleep disturbances. *Ventromedial nucleus* - The **ventromedial nucleus of the hypothalamus** is primarily involved in regulating **satiety** and metabolism. - Damage to this nucleus is more likely to cause symptoms like **hyperphagia** and obesity, not excessive sleepiness. *Preoptic nucleus* - The **preoptic nucleus** is involved in **thermoregulation** and aspects of sleep regulation, particularly the initiation of NREM sleep. - While it has a role in sleep, the **suprachiasmatic nucleus** is the primary driver of the overall circadian rhythm and sustained excessive sleepiness observed here. *Supraoptic nucleus* - The **supraoptic nucleus** is a neurosecretory nucleus in the hypothalamus responsible for producing **vasopressin (ADH)** and **oxytocin**. - Damage to this nucleus would primarily result in **diabetes insipidus** due to ADH deficiency, not disturbances in the sleep-wake cycle.

Endocrine system (thyroid, adrenal, pancreas) US Medical PG Question 10: A 60-year-old man with type 2 diabetes on metformin and insulin presents with 3 days of nausea, vomiting, and diffuse abdominal pain. He appears ill and confused. Vital signs: BP 95/60 mmHg, HR 115/min, RR 28/min, T 37.2°C. Labs show glucose 380 mg/dL, pH 7.28, HCO3 18 mEq/L, anion gap 24, serum osmolality 310 mOsm/kg, negative urine ketones, creatinine 2.8 mg/dL (baseline 1.1), lactate 8.2 mmol/L. Apply physiological principles to determine the primary acid-base and metabolic disturbance.

• A. Sepsis-induced lactic acidosis with stress hyperglycemia
• B. Hyperosmolar hyperglycemic state complicated by lactic acidosis from metformin (Correct Answer)
• C. Alcoholic ketoacidosis with concurrent diabetic emergency
• D. Diabetic ketoacidosis with renal failure from volume depletion
• E. Mixed metabolic acidosis from uremia and starvation ketosis

Endocrine system (thyroid, adrenal, pancreas) Explanation: ***Hyperosmolar hyperglycemic state complicated by lactic acidosis from metformin*** - The patient exhibits features of **Hyperosmolar Hyperglycemic State (HHS)**, including significant hyperglycemia and confusion, but the **negative urine ketones** effectively rule out DKA. - The severe **high anion gap metabolic acidosis** is driven by a **lactate of 8.2 mmol/L**, likely due to **Metformin-Associated Lactic Acidosis (MALA)** triggered by **acute kidney injury** (creatinine 2.8). *Sepsis-induced lactic acidosis with stress hyperglycemia* - While the patient is hypotensive and tachycardic, the **serum glucose of 380 mg/dL** and history of insulin use point primarily to a diabetic emergency rather than simple stress hyperglycemia. - **Lactic acidosis** in sepsis usually occurs alongside clinical signs of infection, which are not the focus of this metformin-using patient's profile. *Alcoholic ketoacidosis with concurrent diabetic emergency* - **Alcoholic ketoacidosis** would typically present with a history of alcohol abuse and **positive ketones** (specifically beta-hydroxybutyrate), which contradicts the **negative urine ketones** found here. - The primary source of acidosis in this patient is clearly identified as **lactate (8.2 mmol/L)**, not ketoacids. *Diabetic ketoacidosis with renal failure from volume depletion* - **Diabetic Ketoacidosis (DKA)** is unlikely given the **negative urine ketones** and a pH/bicarbonate profile that is less severe than typically seen in profound ketoacidosis. - DKA usually presents with a lower glucose level (often <250-300 mg/dL) compared to the hyperosmolar states seen in **Type 2 Diabetes** patients. *Mixed metabolic acidosis from uremia and starvation ketosis* - While **uremia** contributes to the anion gap when creatinine is elevated (2.8 mg/dL), it is rarely the primary cause of an **anion gap of 24** without more advanced renal failure. - **Starvation ketosis** would result in positive ketones and a much milder acidosis than the profound **lactic acidosis** (8.2 mmol/L) observed in this case.

Endocrine system (thyroid, adrenal, pancreas) Flashcard 1 of 10

Question: Thyroid-stimulating hormone (TSH) secretion is decreased in response to _____

Answer: free T3/T4

Endocrine system (thyroid, adrenal, pancreas) Flashcard 2 of 10

Question: Which endocrine hormones use receptor-associated tyrosine kinases as their signaling pathway (4 +2 bonus)?_____

Answer: Prolactin, Growth hormone, Erythropoetin and Leptin (4)

Endocrine system (thyroid, adrenal, pancreas) Flashcard 3 of 10

Question: Overall, the effect of cortisol is _____ (anabolic, catabolic)

Answer: catabolic

Endocrine system (thyroid, adrenal, pancreas) Flashcard 4 of 10

Question: _____, an endocrine hormone, is a member of a family of peptides that includes the GI hormones secretin and GIP

Answer: Glucagon

Endocrine system (thyroid, adrenal, pancreas) Flashcard 5 of 10

Question: What form of thyroid hormone is predominately produced by the thyroid gland?_____

Answer: 90% T4

Endocrine system (thyroid, adrenal, pancreas) Flashcard 6 of 10

Question: _____ is a mechanism in which a hormone decreases the number or affinity of its receptors in a target tissue

Answer: Down-regulation

Endocrine system (thyroid, adrenal, pancreas) Flashcard 7 of 10

Question: What effect does somatostatin have on insulin and glucagon secretion? _____

Answer: Decreased secretion

Endocrine system (thyroid, adrenal, pancreas) Flashcard 8 of 10

Question: What thyroid hormone is more potent?_____

Answer: T3 (10 x more potent than T4)

Endocrine system (thyroid, adrenal, pancreas) Flashcard 9 of 10

Question: What is the effect of the FGF gene?

Answer: stimulates mitosis of underlying mesoderm, lengthening of limbs

Endocrine system (thyroid, adrenal, pancreas) Flashcard 10 of 10

Question: autonomic nervous system

Answer: neural crest