Endocrine System: Adrenal Gland Effects Quiz
49 Questions
18 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

What happens to the free cortisol level when CBG levels rise?

  • It fluctuates randomly
  • It stays the same
  • It increases
  • It drops initially (correct)

What is the role of bound steroids in the body?

  • They enhance cortisol production
  • They directly stimulate ACTH secretion
  • They accelerate glucocorticoid catabolism
  • They are inactive and act as a hormone reservoir (correct)

Where is cortisol primarily metabolized in the body?

  • Liver (correct)
  • Lungs
  • Muscle tissue
  • Kidneys

What makes cortisone an active glucocorticoid?

<p>Its conversion to cortisol before exerting effects (A)</p> Signup and view all the answers

What is the primary function of the aldosterone-secreting mechanism?

<p>Defense of intravascular volume (A)</p> Signup and view all the answers

What effect does standing and constriction of the thoracic inferior vena cava have on intrarenal arterial pressure?

<p>Decreases intrarenal arterial pressure (C)</p> Signup and view all the answers

What is one of the major factors affecting Na+ excretion, apart from variations in aldosterone secretion?

<p>ANP (Atrial Natriuretic Peptide) (D)</p> Signup and view all the answers

What is the effect of glucocorticoids on ACTH secretion?

<p>Inhibit ACTH secretion (A)</p> Signup and view all the answers

What occurs when one rises from the supine to the standing position in terms of aldosterone secretion?

<p>Increases aldosterone secretion (D)</p> Signup and view all the answers

Which organ shows a decrease in the number of eosinophils due to the effects of glucocorticoids?

<p>Spleen (A)</p> Signup and view all the answers

What can happen if patients with adrenal insufficiency receive a glucose infusion without glucocorticoids?

<p>High fever ('glucose fever') followed by collapse and death (C)</p> Signup and view all the answers

What changes in the nervous system are reversed only by glucocorticoids in adrenal insufficiency?

<p>Slower than normal β rhythm in electroencephalographic waves (C)</p> Signup and view all the answers

What happens to most of the cortisone formed in the liver?

<p>It is promptly reduced and conjugated to form tetrahydrocortisone glucuronides. (B)</p> Signup and view all the answers

What is the major adrenal androgen mentioned in the text?

<p>Dehydroepiandrosterone (D)</p> Signup and view all the answers

What is the effect of androgens according to the text?

<p>They promote protein anabolism and growth. (C)</p> Signup and view all the answers

How does aldosterone's half-life compare to cortisol?

<p>Aldosterone has a much shorter half-life than cortisol. (A)</p> Signup and view all the answers

How do norepinephrine and epinephrine affect the secretion of insulin and glucagon?

<p>Increase insulin secretion via α-adrenergic mechanisms and inhibit glucagon secretion via β-adrenergic mechanisms (C)</p> Signup and view all the answers

Which adrenergic receptors mediate the vasoconstriction produced by norepinephrine?

<p>α1-receptors (B)</p> Signup and view all the answers

What is the physiologic function of dopamine in the circulation?

<p>Causes renal vasodilation (A)</p> Signup and view all the answers

How does dopamine exert its positive inotropic effect on the heart?

<p>By acting on β1-adrenergic receptors (C)</p> Signup and view all the answers

What is the enzyme responsible for converting cholesterol to pregnenolone in the mitochondria?

<p>Pregnenolone dehydrogenase (A)</p> Signup and view all the answers

Which protein binds cortisol in the circulation?

<p>Transcortin (B)</p> Signup and view all the answers

What is the primary mineralocorticoid secreted in roughly equal amounts to deoxycorticosterone according to the text?

<p>Aldosterone (C)</p> Signup and view all the answers

Which hormone activates adenylyl cyclase via Gs in adrenocortical cells?

<p>ACTH (B)</p> Signup and view all the answers

How do mineralocorticoids like aldosterone affect Na+ reabsorption?

<p>Cause Na+ retention in extracellular fluid (A)</p> Signup and view all the answers

What is the mechanism of action of aldosterone in promoting sodium reabsorption?

<p>Indirectly increases the synthesis of epithelial sodium channels (ENaCs) (A)</p> Signup and view all the answers

What effect does a drop in resting corticoid levels have on ACTH secretion?

<p>Stimulates ACTH secretion (C)</p> Signup and view all the answers

Where does aldosterone bind to initiate its cellular action?

<p>Cytoplasmic receptor (B)</p> Signup and view all the answers

What is the primary regulatory factor involved in increasing aldosterone secretion from the adrenal gland?

<p>Renin from the kidney via angiotensin II (B)</p> Signup and view all the answers

Which condition selectively affects the output of aldosterone without affecting glucocorticoid secretion?

<p>High potassium intake (C)</p> Signup and view all the answers

What effect does a direct rise in plasma K+ concentration have on the adrenal cortex?

<p>Stimulatory effect (A)</p> Signup and view all the answers

Which factor stimulates the output of aldosterone, glucocorticoids, and sex hormones when first administered?

<p>ACTH (D)</p> Signup and view all the answers

What is the primary effect of aldosterone on Na+ reabsorption?

<p>Increase in reabsorption from urine (D)</p> Signup and view all the answers

How does aldosterone affect the exchange of Na+ for K+ in the renal tubules?

<p>Promotes exchange of Na+ for K+ (C)</p> Signup and view all the answers

What is the mechanism by which aldosterone stimulates ENaC activity?

<p>Stimulates ENaC insertion (D)</p> Signup and view all the answers

How does a drop in resting corticoid levels affect ACTH secretion?

<p>Increases ACTH secretion (B)</p> Signup and view all the answers

What happens to urine acidity under the influence of aldosterone?

<p>Increases (C)</p> Signup and view all the answers

How do mineralocorticoids like aldosterone affect ECF volume?

<p>Increase it (D)</p> Signup and view all the answers

Signup and view all the answers

Glucocorticoids inhibit ACTH secretion.

<p>True (A)</p> Signup and view all the answers

Adrenal insufficiency is characterized by an inability to excrete a water load.

<p>True (A)</p> Signup and view all the answers

In adrenal insufficiency, glucose infusion without glucocorticoids can lead to high fever and collapse.

<p>True (A)</p> Signup and view all the answers

Glucocorticoids decrease the number of circulating eosinophils.

<p>True (A)</p> Signup and view all the answers

Glucocorticoids increase the number of basophils in circulation.

<p>False (B)</p> Signup and view all the answers

Adrenal insufficiency results in the possibility of water intoxication.

<p>True (A)</p> Signup and view all the answers

The appearance of slower electroencephalographic waves in adrenal insufficiency is reversed only by mineralocorticoids.

<p>False (B)</p> Signup and view all the answers

Neutrophils' numbers decrease due to the effects of glucocorticoids.

<p>False (B)</p> Signup and view all the answers

Personality changes in adrenal insufficiency include irritability and inability to concentrate.

<p>True (A)</p> Signup and view all the answers

Glucocorticoids increase ketone body formation in diabetics.

<p>True (A)</p> Signup and view all the answers

Flashcards

Stress (biological definition)

Any environmental change that threatens the optimal steady state of an organism.

Homeostatic Reactions

The body's mechanism to restore balance after a stressful event.

Adrenocorticotropic Hormone (ACTH)

A hormone secreted by the pituitary gland in response to stress.

Cushing Syndrome

A condition characterized by prolonged elevated levels of cortisol, the main glucocorticoid.

Signup and view all the flashcards

Glucocorticoids

Hormones produced by the adrenal glands that regulate metabolism, immune function, and stress response.

Signup and view all the flashcards

Adrenal Cortex

The outer layer of the adrenal glands, responsible for producing steroid hormones.

Signup and view all the flashcards

Adrenal Medulla

The inner layer of the adrenal glands, responsible for producing catecholamines like adrenaline.

Signup and view all the flashcards

Cholesterol

A precursor molecule for all steroid hormones, including cortisol.

Signup and view all the flashcards

Corticosteroid-binding Globulin (CBG)

A protein that binds to cortisol in the bloodstream, influencing its availability.

Signup and view all the flashcards

Cortisol

The primary hormone secreted by the adrenal cortex, involved in stress response and metabolism.

Signup and view all the flashcards

Cortisone

A synthetic glucocorticoid medication used to treat inflammation.

Signup and view all the flashcards

Cortisol Metabolism

The process of breaking down cortisol in the body, mainly by the liver.

Signup and view all the flashcards

Hypokalemia

A condition characterized by muscle weakness, low potassium levels, and high blood pressure, often associated with Cushing Syndrome.

Signup and view all the flashcards

Anti-inflammatory Properties of Glucocorticoids

The ability of glucocorticoids to reduce inflammation and suppress the immune response.

Signup and view all the flashcards

Diurnal Rhythm of Cortisol Secretion

The daily fluctuation in cortisol levels, peaking in the morning.

Signup and view all the flashcards

Feedback Mechanism of Glucocorticoid Secretion

A feedback mechanism where cortisol levels inhibit the release of ACTH, maintaining balance.

Signup and view all the flashcards

Mineralocorticoids

A hormone that directly affects blood pressure by increasing sodium retention.

Signup and view all the flashcards

Cholesterol Conversion to Pregnenolone

The process of converting cholesterol to pregnenolone, the first step in steroid synthesis.

Signup and view all the flashcards

Adrenal Cortex (Sex Hormone Production)

The part of the adrenal glands that produces hormones that regulate sexual development and reproductive functions.

Signup and view all the flashcards

Adrenal Physiology

The scientific study of the adrenal glands and their hormones.

Signup and view all the flashcards

Cortisol Activation

The process of converting cortisol to its active form, allowing it to exert its effects.

Signup and view all the flashcards

Half-life of a substance

The half-life of a substance in the body, indicating how long it takes for half of it to be eliminated.

Signup and view all the flashcards

Bioavailability

The amount of a substance that is available to exert its effects.

Signup and view all the flashcards

Hypercortisolism

The condition where the body produces too much cortisol, leading to various symptoms.

Signup and view all the flashcards

Glucocorticoid Effects on Vascular Reactivity

The effect of glucocorticoids on blood vessels, potentially contributing to hypertension.

Signup and view all the flashcards

ACTH-induced Adrenal Sensitivity

The process by which ACTH enhances the adrenal glands' sensitivity to subsequent doses of ACTH.

Signup and view all the flashcards

Hirsutism

The condition characterized by excessive facial hair growth in women.

Signup and view all the flashcards

Buffalo Hump

The accumulation of fat in the abdomen, face, and upper back, giving a characteristic shape.

Signup and view all the flashcards

Moon Face

The rounded appearance of the face due to fat accumulation.

Signup and view all the flashcards

Adrenal Endocrinology

The scientific study of the adrenal glands and their disorders.

Signup and view all the flashcards

Study Notes

Stress and the Adrenal Gland

  • Stress, in biological terms, refers to any environmental change threatening the optimal steady state.
  • Stressors trigger homeostatic reactions at molecular, cellular, or systemic levels to restore balance.
  • Severe stress significantly increases Adrenocorticotropic Hormone (ACTH) secretion, crucial for survival.
  • Most stimuli inducing ACTH also activate the sympathetic nervous system, highlighting glucocorticoids’ role in vascular reactivity.
  • Long-term elevated ACTH can lead to adverse effects, including Cushing syndrome.

Cushing Syndrome

  • Characterized by prolonged elevated plasma glucocorticoids, first described by Harvey Cushing.
  • Symptoms include protein depletion, leading to thin skin and poorly developed muscle; hair may become thin and scraggly.
  • Increased androgens cause facial hair growth and acne.
  • Body fat redistributes, resulting in thin extremities and accumulation in the abdomen, face, and upper back, leading to a “buffalo hump” appearance.
  • Notable "moon-faced" rounded appearance from facial obesity; often accompanied by significant potassium depletion and muscle weakness.
  • Approximately 85% of patients experience hypertension, potentially due to increased deoxycorticosterone or direct glucocorticoid effects.

Glucocorticoid Functions

  • Glucocorticoids possess anti-inflammatory properties, inhibiting tissue injury responses and allergic reactions caused by histamine.
  • High circulating glucocorticoids are necessary for these anti-inflammatory effects, as low steroid doses may not replicate these benefits.

Regulation of Glucocorticoid Secretion

  • ACTH from the anterior pituitary regulates basal and stress-induced glucocorticoid secretion, with a half-life of ~10 minutes.
  • ACTH enhances adrenal sensitivity to its subsequent doses, critical for normal adrenal function.
  • ACTH secretions follow a diurnal rhythm, peaking in the early morning, contributing to about 75% of daily cortisol production between 4:00 AM and 10:00 AM.
  • Feedback mechanism: free glucocorticoids inhibit ACTH secretion, aligning inhibition levels with cortisol concentration.

Adrenal Gland Structure and Hormones

  • Composed of two functional parts: inner adrenal medulla (producing catecholamines) and outer adrenal cortex (producing steroid hormones).
  • Adrenal cortex secretes glucocorticoids for carbohydrate and protein metabolism, a mineralocorticoid for sodium balance, and sex hormones affecting reproductive functions.
  • Adrenal medulla consists of 90% epinephrine-secreting cells and 10% norepinephrine-secreting cells.

Steroid Biosynthesis

  • Cholesterol serves as the precursor for all steroids, with origins from both acetate synthesis and uptake from LDL.
  • Cholesterol is converted to pregnenolone in mitochondria, and subsequent steps yield other steroid hormones.
  • ACTH enhances the synthesis of enzymes needed for glucocorticoids.

Transport and Metabolism of Glucocorticoids

  • Cortisol is primarily bound to corticosteroid-binding globulin (CBG), produced in the liver and influenced by estrogen.
  • CBG levels vary with conditions like pregnancy, cirrhosis, and nephrosis impacting cortisol bioavailability.
  • Cortisol has a circulation half-life of 60–90 minutes; only free cortisol is physiologically active.
  • The liver is the main site for cortisol metabolism, converting it to biologically active forms.

Drugs and Clinical Relevance

  • Cortisone is notable in medical use due to its ability to be activated into cortisol. It is not produced in substantial amounts by the adrenal glands.

Studying That Suits You

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

Quiz Team

Related Documents

Endocrine System | Adrenal Gland PDF

Description

Test your knowledge on the effects of adrenal gland hormones on plasma glucose, lipid levels, ketone body formation, ACTH secretion, and the nervous system. Explore negative feedback responses and physiological changes related to adrenal insufficiency.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser