Lecture 4 MCQ Biochem
26 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which one of the following is a characteristic of Conn's syndrome?

  • Deficiency of cortisol
  • Deficiency of aldosterone
  • Excess secretion of cortisol
  • Excess secretion of aldosterone (correct)
  • What is the effect of Conn's syndrome on water and electrolyte balance?

  • Decreased water retention and decreased potassium excretion
  • Increased water retention and decreased potassium excretion (correct)
  • Decreased water retention and increased potassium excretion
  • Increased water retention and increased potassium excretion
  • How can a diagnosis of primary hyperaldosteronism be confirmed?

  • Measurement of plasma aldosterone levels
  • Measurement of plasma sodium levels
  • Measurement of plasma renin levels (correct)
  • Measurement of plasma cortisol levels
  • Which enzyme is deficient in the case of 11 beta hydroxylase deficiency?

    <p>11 beta hydroxysteroid dehydrogenase</p> Signup and view all the answers

    What is the expected level of serum 17-(OH)-progesterone in the case of 11 beta hydroxylase deficiency?

    <p>1000</p> Signup and view all the answers

    What is the expected level of 24 h urine pregnanetriol in the case of 11 beta hydroxylase deficiency?

    <p>2.8</p> Signup and view all the answers

    Will renin be elevated in the case of 11 beta hydroxylase deficiency?

    <p>Yes</p> Signup and view all the answers

    Which of the following is a direct effect of aldosterone?

    <p>Increased thirst</p> Signup and view all the answers

    Which of the following is a primary cause of hyperaldosteronism?

    <p>Adrenal adenoma</p> Signup and view all the answers

    What is the primary stimulus for aldosterone secretion?

    <p>Low circulating volume</p> Signup and view all the answers

    How can primary hyperaldosteronism be diagnosed?

    <p>All of the above</p> Signup and view all the answers

    Which of the following is the primary stimulus for aldosterone secretion in the renin-angiotensin system?

    <p>Decreased renal blood flow</p> Signup and view all the answers

    Which of the following is a consequence of excess aldosterone secretion?

    <p>Metabolic alkalosis</p> Signup and view all the answers

    Which of the following factors independently stimulates aldosterone secretion?

    <p>Plasma potassium levels</p> Signup and view all the answers

    What is the main role of aldosterone in the body?

    <p>Maintaining sodium and water balance</p> Signup and view all the answers

    Which enzyme deficiency is the most common cause of Congenital Adrenal Hyperplasia (CAH)?

    <p>21 hydroxylase deficiency</p> Signup and view all the answers

    Which hormone is primarily affected in CAH?

    <p>Cortisol</p> Signup and view all the answers

    What is the main effect of severe 21 hydroxylase deficiency on aldosterone synthesis?

    <p>Variable effect on aldosterone synthesis</p> Signup and view all the answers

    What is the main effect of severe 21 hydroxylase deficiency on androgen synthesis?

    <p>Increased androgen synthesis</p> Signup and view all the answers

    Which of the following is a characteristic of adrenal adenomas and carcinomas compared to FHA and unilateral hyperplasia?

    <p>All of the above</p> Signup and view all the answers

    Which gene is involved in the unequal crossing over between 11b hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes in Familial Hyperaldosteronism type I (FHI)?

    <p>Both CYP11B1 and CYP11B2</p> Signup and view all the answers

    Which of the following drugs inhibits 11 beta hydroxysteroid dehydrogenase and can lead to increased aldosterone levels?

    <p>Liquorice</p> Signup and view all the answers

    Which of the following is a common finding in primary hyperaldosteronism?

    <p>Low plasma potassium</p> Signup and view all the answers

    What is the expected urine potassium level in a patient with an adrenal tumor causing primary hyperaldosteronism?

    <p>High</p> Signup and view all the answers

    What is the cause of Liddle's syndrome?

    <p>Mutations in eNAC in renal tubule cells</p> Signup and view all the answers

    What is the primary cause of hyperaldosteronism in Bartter's syndrome?

    <p>Impaired ADH responsiveness</p> Signup and view all the answers

    Study Notes

    Characteristics of Conn's Syndrome

    • Hypertension and hypokalemia are characteristic of Conn's syndrome
    • Conn's syndrome is a consequence of excess aldosterone secretion

    Effect on Water and Electrolyte Balance

    • Excess aldosterone secretion leads to water retention and potassium depletion
    • This can result in hypokalemia and hypertension

    Diagnosis of Primary Hyperaldosteronism

    • Primary hyperaldosteronism can be diagnosed with adrenal vein sampling
    • This is used to lateralize aldosterone secretion to one adrenal gland

    11 Beta Hydroxylase Deficiency

    • 11 beta hydroxylase deficiency is an autosomal recessive disorder
    • 11 beta hydroxylase is an enzyme involved in cortisol synthesis
    • Deficiency of this enzyme leads to increased levels of 17-alpha-hydroxyprogesterone
    • This results in virilization and hypertension

    Serum and Urine Levels in 11 Beta Hydroxylase Deficiency

    • Serum 17-alpha-hydroxyprogesterone levels are elevated in 11 beta hydroxylase deficiency
    • 24-hour urine pregnanetriol levels are also elevated in this condition
    • Renin levels are decreased in 11 beta hydroxylase deficiency due to volume expansion

    Effects of Aldosterone

    • Aldosterone stimulates sodium reabsorption and potassium excretion in the distal nephron
    • This leads to hypertension and hypokalemia

    Causes of Hyperaldosteronism

    • Primary hyperaldosteronism is caused by adrenal adenoma or carcinoma
    • Secondary hyperaldosteronism is caused by renovascular disease or reninoma

    Regulation of Aldosterone Secretion

    • Aldosterone secretion is stimulated by angiotensin II, potassium, and ACTH
    • The renin-angiotensin-aldosterone system is the primary regulator of aldosterone secretion

    Diagnosis of Congenital Adrenal Hyperplasia (CAH)

    • CAH is caused by 21 hydroxylase deficiency in 90% of cases
    • CAH leads to virilization and ambiguous genitalia in females

    Effects of 21 Hydroxylase Deficiency

    • 21 hydroxylase deficiency leads to decreased aldosterone synthesis
    • This results in salt wasting and hypotension
    • 21 hydroxylase deficiency also leads to increased androgen synthesis
    • This results in virilization and ambiguous genitalia in females

    Adrenal Tumors

    • Adrenal adenomas and carcinomas are frequently unilateral
    • They are characterized by unilateral adrenal hyperplasia

    Familial Hyperaldosteronism Type I (FHI)

    • FHI is caused by unequal crossing over between CYP11B1 and CYP11B2 genes
    • This results in the ectopic expression of aldosterone synthase in the adrenal zona fasciculata

    Inhibitors of 11 Beta-Hydroxysteroid Dehydrogenase

    • Glycyrrhetinic acid inhibits 11 beta-hydroxysteroid dehydrogenase
    • This leads to increased aldosterone levels and hypertension

    Primary Hyperaldosteronism

    • Primary hyperaldosteronism is characterized by hypertension and hypokalemia
    • Urine potassium levels are decreased in primary hyperaldosteronism

    Liddle's Syndrome

    • Liddle's syndrome is caused by activating mutations of the beta subunit of the epithelial sodium channel
    • This results in excessive sodium reabsorption and hypertension

    Bartter's Syndrome

    • Bartter's syndrome is caused by mutations of the thick ascending limb of the loop of Henle
    • This results in excessive potassium wasting and hypokalemia

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Test your knowledge on aldosterone deficiency, deoxycorticosterone, virilization, hypertension, and urinary 17-hydroxycorticosteroids. Explore the differences from 11 b hydroxysteroid dehydrogenase and learn about pregnenolone, progesterone, 11-deoxycorticosterone, corticosterone, and aldosterone. Take the quiz now!

    More Like This

    Use Quizgecko on...
    Browser
    Browser