Endocrine System: Antidiuretic Hormone (ADH)
47 Questions
0 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 role does antidiuretic hormone (ADH) play in the body?

  • It decreases urine output and increases water reabsorption. (correct)
  • It increases urine output to reduce body water.
  • It regulates body temperature through perspiration.
  • It is produced in the kidneys to filter blood.

What triggers the release of ADH from the pituitary gland?

  • An increase in blood volume.
  • A rise in blood pressure.
  • Concentration of blood solutes increasing. (correct)
  • Dehydration of the skin.

How do osmoreceptors function in the regulation of ADH?

  • They release ADH when blood pressure rises.
  • They detect changes in osmotic pressure and trigger nerve signals. (correct)
  • They regulate temperature to promote water loss.
  • They filter blood through the kidneys.

What effect does increased ADH have on urine concentration?

<p>It results in more concentrated urine. (D)</p> Signup and view all the answers

What happens to the cells of the hypothalamus when blood solutes become concentrated?

<p>They shrink and send a message for ADH release. (C)</p> Signup and view all the answers

What happens to the osmotic pressure of the blood when more water is consumed?

<p>It decreases. (B)</p> Signup and view all the answers

How do fluids move in response to lower osmotic pressure in the blood?

<p>They move from the blood into the hypothalamus. (C)</p> Signup and view all the answers

What is the effect of alcohol on the release of ADH?

<p>It decreases the release of ADH. (B)</p> Signup and view all the answers

Which segment of the nephron is permeable to water and ions?

<p>Descending loop of Henle. (D)</p> Signup and view all the answers

What concentration gradient is created by the active transport of Na+ ions in the nephron?

<p>Solutes concentrate within the medulla of the kidney. (B)</p> Signup and view all the answers

What occurs in the absence of ADH concerning water reabsorption in the nephron?

<p>The remaining 15% of water filtered is lost. (D)</p> Signup and view all the answers

What happens to urine concentration in the nephron when ADH makes cell membranes more permeable?

<p>Urine becomes more concentrated. (D)</p> Signup and view all the answers

What is the primary purpose of sports drinks compared to water?

<p>To restore electrolytes lost during physical activity. (B)</p> Signup and view all the answers

What triggers the sensation of thirst in the body?

<p>Shrinking of cells in the hypothalamus (D)</p> Signup and view all the answers

Which hormone is released by the pituitary gland to help regulate osmotic pressure?

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

What is the primary role of osmoreceptors located in the hypothalamus?

<p>To detect changes in osmotic pressure (A)</p> Signup and view all the answers

How does ADH contribute to maintaining homeostasis in the body?

<p>By increasing water reabsorption in the kidneys (D)</p> Signup and view all the answers

What effect does increased osmotic pressure in the blood have on the hypothalamus?

<p>Cells become dehydrated and shrink (B)</p> Signup and view all the answers

What is one of the consequences of drinking water in response to thirst?

<p>It decreases the rate of urine production (D)</p> Signup and view all the answers

What happens to ADH release when blood osmotic pressure is high?

<p>ADH release increases (B)</p> Signup and view all the answers

What physiological mechanism prevents dehydration when osmotic pressure rises?

<p>Increase in water reabsorption in the kidneys (B)</p> Signup and view all the answers

What is the primary role of the kidneys in maintaining the pH of body fluids?

<p>Regulating the secretion of H+ ions (B)</p> Signup and view all the answers

Where is ADH primarily produced in the body?

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

What physiological change occurs in response to increased osmotic pressure in body fluids?

<p>Increased secretion of ADH (C)</p> Signup and view all the answers

Which of the following substances is typically not filtered from the blood into Bowman’s capsule?

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

How does aldosterone help to maintain blood pressure?

<p>By promoting sodium retention (A)</p> Signup and view all the answers

What role does the thirst center play in response to osmotic pressure changes?

<p>Encourages water consumption (D)</p> Signup and view all the answers

If the kidneys fail to excrete H+ ions, which substance would most likely increase in the blood?

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

Which of the following statements about the HCO3- buffering system is true?

<p>It acts to neutralize excessive H+ ions. (C)</p> Signup and view all the answers

What percentage of water essential for nerve operation is controlled by the kidneys?

<p>15% (D)</p> Signup and view all the answers

How do the kidneys regulate the osmotic concentrations of body fluids?

<p>By varying water reabsorption (A)</p> Signup and view all the answers

Which hormone is primarily responsible for increasing Na+ reabsorption in the nephrons?

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

Where is aldosterone produced in the body?

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

What effect does increased NaCl reabsorption have on water movement in the nephron?

<p>More water moves out by osmosis (D)</p> Signup and view all the answers

What physiological condition could the kidneys respond to in order to regulate blood pressure?

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

What triggers the release of aldosterone from the adrenal glands?

<p>Low blood pressure detected by juxtaglomerular apparatus (A)</p> Signup and view all the answers

What effect does the hormone angiotensin have on the blood vessels?

<p>Causes constriction of blood vessels (B)</p> Signup and view all the answers

Which specialized cells are involved in the release of renin?

<p>Cells within the juxtaglomerular apparatus (C)</p> Signup and view all the answers

What is the primary function of aldosterone?

<p>Maintain Na+ and water homeostasis (D)</p> Signup and view all the answers

What is the primary role of the bicarbonate-carbon dioxide buffer system?

<p>To maintain pH balance (A)</p> Signup and view all the answers

What happens to CO2 that is transported from the peritubular capillaries?

<p>It combines with water to generate bicarbonate ions. (B)</p> Signup and view all the answers

How do the kidneys help restore the bicarbonate buffer?

<p>By reversing the reaction that generates bicarbonate. (C)</p> Signup and view all the answers

What is the function of aldosterone in the body's fluid regulation?

<p>To control the absorption of sodium ions. (B)</p> Signup and view all the answers

Which ion is most likely to combine with H+ ions for excretion in the filtrate?

<p>Phosphate (HPO4^2-) (D)</p> Signup and view all the answers

What mechanism regulates the actions of antidiuretic hormone (ADH)?

<p>Negative feedback. (B)</p> Signup and view all the answers

During the bicarbonate buffer restoration, what reacts with H+ ions to aid in excretion?

<p>Ammonia (NH3) (C)</p> Signup and view all the answers

What occurs to bicarbonate ions after their formation in the nephron cells?

<p>They diffuse back into the blood. (D)</p> Signup and view all the answers

Flashcards

Antidiuretic hormone (ADH)

A hormone that helps control the concentration of bodily fluids by regulating how much water the kidneys reabsorb.

Osmoreceptors

Specialized nerve cells in the hypothalamus responsible for sensing changes in the osmotic pressure of blood.

Water Balance

The process by which the body maintains the proper balance of water and solutes in its fluids.

Osmotic Pressure

The concentration of dissolved substances (like salts) in a solution.

Signup and view all the flashcards

Extracellular Fluid (ECF)

The fluid outside of cells, such as blood plasma, lymph, and cerebrospinal fluid.

Signup and view all the flashcards

What is osmotic pressure?

The concentration of dissolved substances (like salts) in a solution.

Signup and view all the flashcards

What are osmoreceptors?

Specialized nerve cells in the hypothalamus that detect changes in blood osmotic pressure.

Signup and view all the flashcards

What is antidiuretic hormone (ADH)?

A hormone released by the pituitary gland that helps conserve water in the body by increasing water reabsorption in the kidneys.

Signup and view all the flashcards

How does the body respond to low blood osmotic pressure?

When osmoreceptors detect a decrease in blood osmotic pressure, they send a message to the pituitary gland. This causes the release of ADH, which promotes water reabsorption in the kidneys and lowers the blood osmotic pressure back to normal.

Signup and view all the flashcards

How does the body respond to thirst?

A sensation of thirst is triggered when the osmoreceptors detect a decrease in blood osmotic pressure. This is a behavioral response aimed at increasing water intake and restoring the blood osmotic pressure to normal.

Signup and view all the flashcards

What is water balance?

The body's process of regulating and maintaining the appropriate balance of water and dissolved substances in its fluids.

Signup and view all the flashcards

What is extracellular fluid (ECF)?

The fluid outside of cells, including blood plasma, lymph, and cerebrospinal fluid.

Signup and view all the flashcards

How does the body respond to high blood osmotic pressure?

When osmoreceptors detect an increase in blood osmotic pressure, the body responds by stimulating thirst and releasing ADH. These mechanisms help bring the osmotic pressure back to normal by increasing water intake and reabsorption.

Signup and view all the flashcards

ADH release and blood dilution

When the blood becomes more diluted, the osmoreceptors in the hypothalamus swell, reducing the release of ADH, leading to less water reabsorption in the kidneys and more water in urine.

Signup and view all the flashcards

Urine formation

The process of the kidneys filtering waste products from the blood and producing urine.

Signup and view all the flashcards

ADH and collecting duct

When ADH is released, the collecting duct of the nephron becomes permeable to water, allowing more water to be reabsorbed into the bloodstream.

Signup and view all the flashcards

Collecting duct

The portion of the nephron where ADH primarily acts to influence water reabsorption.

Signup and view all the flashcards

Ascending loop of Henle

The segment of the nephron that is only permeable to NaCl (salt).

Signup and view all the flashcards

Kidney's Role in Acid-Base Balance

The process by which the kidneys help to restore the body's acid-base balance. It involves removing excess hydrogen ions from the blood and excreting them in the urine.

Signup and view all the flashcards

Peritubular Capillaries

The network of tiny blood vessels surrounding the nephron, where substances are exchanged between the blood and the nephron.

Signup and view all the flashcards

CO2 Diffusion and Carbonic Acid Formation

Carbon dioxide (CO2) diffuses from the peritubular capillaries into the cells surrounding the nephron, where it combines with water to form carbonic acid (H2CO3).

Signup and view all the flashcards

Carbonic Acid Dissociation

Carbonic acid (H2CO3) dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+).

Signup and view all the flashcards

Bicarbonate Ion Diffusion

Bicarbonate ions (HCO3-) diffuse back into the peritubular capillaries, restoring the bicarbonate buffer in the blood.

Signup and view all the flashcards

Hydrogen Ion Excretion

Hydrogen ions (H+) in the nephron cells combine with either phosphate ions or ammonia, forming acidic compounds that are excreted in the urine.

Signup and view all the flashcards

Water Balance Regulation

The process by which the body regulates the amount of water in the blood and tissues by adjusting the reabsorption of water in the kidneys.

Signup and view all the flashcards

What is ADH?

Antidiuretic hormone (ADH) is a hormone that stimulates water reabsorption in the kidneys, helping to regulate blood volume and concentration.

Signup and view all the flashcards

Where is ADH produced and stored?

ADH is produced in the hypothalamus, a region of the brain, and is stored in the posterior pituitary gland until it is released into the bloodstream.

Signup and view all the flashcards

How is ADH release regulated?

When blood osmotic pressure increases (concentration of dissolved substances rises), osmoreceptors in the hypothalamus detect the change. They send a signal to the posterior pituitary, triggering the release of ADH.

Signup and view all the flashcards

Where is the thirst center located?

The thirst center is located in the hypothalamus, the same brain region where ADH is produced.

Signup and view all the flashcards

What physiological adjustment occurs with increased osmotic pressure?

Increased osmotic pressure in body fluids triggers the release of ADH, promoting water reabsorption by the kidneys. This helps dilute the blood and restore osmotic balance.

Signup and view all the flashcards

What behavioural adjustments occur with increased osmotic pressure?

Behavioral adjustments to increased osmotic pressure include feeling thirsty and seeking fluids. This helps increase water intake and dilute the blood.

Signup and view all the flashcards

How does aldosterone help maintain blood pressure?

Aldosterone, a hormone produced by the adrenal glands, acts on the kidneys to increase sodium reabsorption. This helps maintain blood volume and, consequently, blood pressure.

Signup and view all the flashcards

How do kidneys maintain the pH of body fluids?

The kidneys play a crucial role in regulating the pH of body fluids. They do this by excreting excess H+ (hydrogen) ions and retaining bicarbonate ions (HCO3-), which act as buffers to neutralize acids in the blood.

Signup and view all the flashcards

How do kidneys regulate fluid concentration?

Kidneys maintain fluid balance by adjusting water reabsorption in the nephron, impacting the concentration of dissolved substances in body fluids.

Signup and view all the flashcards

How does aldosterone affect water reabsorption?

Aldosterone, a hormone produced by the adrenal glands, increases sodium reabsorption in the distal tubule and collecting duct of the nephron, influencing water reabsorption due to osmotic pressure.

Signup and view all the flashcards

What triggers renin release?

The juxtaglomerular apparatus, a specialized structure in the kidney, releases renin in response to low blood pressure.

Signup and view all the flashcards

What is renin's role in blood pressure regulation?

Renin, an enzyme released by the juxtaglomerular apparatus, converts angiotensinogen into angiotensin I, initiating a signaling cascade that regulates blood pressure.

Signup and view all the flashcards

How does Angiotensin II affect blood pressure?

Angiotensin II, a powerful vasoconstrictor, constricts blood vessels, increasing blood pressure, and also stimulates aldosterone release, further contributing to blood pressure regulation.

Signup and view all the flashcards

How do kidneys contribute to blood pressure regulation?

The kidneys act on blood volume to regulate blood pressure, promoting fluid retention through mechanisms like aldosterone release.

Signup and view all the flashcards

Where is aldosterone produced and what is its function?

Aldosterone is released by adrenal glands, located above the kidneys, and plays a critical role in the regulation of sodium and, consequently, water reabsorption.

Signup and view all the flashcards

What is the renin-angiotensin system?

The renin-angiotensin system, a complex pathway triggered by low blood pressure, utilizes renin to activate angiotensin, leading to vasoconstriction and aldosterone release, ultimately raising blood pressure.

Signup and view all the flashcards

What percentage of water reabsorption do kidneys regulate?

The kidneys control the last 15% of water reabsorption in the nephron, ensuring precise regulation of the body's fluid balance.

Signup and view all the flashcards

What is the overall importance of kidneys in the body?

The kidneys play a crucial role in maintaining homeostasis by regulating blood pressure and fluid balance through hormonal pathways and specialized structures.

Signup and view all the flashcards

Study Notes

Water Balance

  • The body regulates water intake and output through interactions between the nervous and endocrine systems.
  • Increased water intake leads to increased urine output, and vice versa.
  • Decreased water intake or increased exercise reduces urine output.
  • Antidiuretic hormone (ADH) regulates osmotic pressure by controlling water reabsorption in the kidneys.
  • ADH is produced in the hypothalamus and stored in the pituitary gland.
  • Osmoreceptors in the hypothalamus detect changes in blood osmotic pressure.
  • When blood osmotic pressure increases (e.g., dehydration), cells in the hypothalamus shrink, sending a signal to release ADH.
  • ADH is carried in the bloodstream to the kidneys, increasing water reabsorption.
  • This prevents further increases in blood osmotic pressure and conserves water.
  • The sensation of thirst is initiated by shrinking cells in the hypothalamus.
  • Drinking water decreases blood osmotic pressure, causing the cells to swell and reducing further ADH release.
  • Less water is reabsorbed in the nephrons.

Regulating ADH

  • ADH helps control body fluid osmotic pressure by causing kidneys to control water reabsorption.
  • Released ADH results in more concentrated urine, conserving water.
  • Specialized nerve cells in hypothalamus (osmoreceptors) detect changes in osmotic pressure.
  • Reduced water intake/increased water loss causes a rise in blood solute concentration, leading to higher osmotic pressure.
  • Water moves to the bloodstream, causing hypothalamic cells to shrink.
  • Shrinking cells send signals to the pituitary gland, triggering the release of ADH.
  • ADH is transported via bloodstream to kidneys, increasing water reabsorption.
  • This prevents osmotic pressure from rising further.
  • The shrinking of hypothalamic cells also stimulates thirst response.

ADH and the Nephron

  • Approximately 85% of filtered water is reabsorbed in the proximal tubule.
  • The descending loop of Henle allows for water permeability.
  • The ascending loop is permeable to sodium (NaCl), concentrating solutes in the kidney medulla.
  • Without ADH, the remaining 15% of filtered water is lost in urine.
  • ADH makes the distal tubule and collecting duct permeable to water.
  • High NaCl concentration in interstitial spaces forces water from nephron to blood.
  • This concentrates urine and regulates osmotic concentrations in body fluids. The kidneys precisely control the last 15% of water.

Kidneys and Blood Pressure

  • Kidneys adjust blood volume to regulate blood pressure.
  • Aldosterone, a hormone produced in the adrenal cortex, increases sodium (Na⁺) reabsorption in nephrons.
  • Increased Na⁺ reabsorption leads to increased water reabsorption (osmosis).
  • This increases blood volume (and blood pressure).
  • Blood pressure receptors in the juxtaglomerular apparatus detect low blood pressure.
  • This triggers the release of renin, an enzyme that converts angiotensinogen to angiotensin.
  • Angiotensin constricts blood vessels and stimulates aldosterone production, maintaining blood pressure.

pH Balance

  • Kidneys maintain blood pH between 7.3 and 7.5.
  • Cellular respiration produces CO₂ which forms carbonic acid (H₂CO₃) and increases H⁺ concentration, lowering pH.
  • Bicarbonate ions (HCO₃⁻) act as a buffer, absorbing excess H⁺ ions.
  • HCO₃⁻ reacts with excess H⁺ to form carbonic acid.
  • Carbonic acid breaks down into CO₂ and water, which are exhaled from the lungs.
  • Kidneys reverse this reaction by reabsorbing bicarbonate to raise pH when needed.
  • Kidneys excrete excess H⁺ ions if blood pH falls.

Summary

  • Antidiuretic hormone (ADH) regulates osmotic pressure and fluid volume.
  • Aldosterone regulates fluid volume by affecting sodium absorption.
  • Kidneys play a crucial role in restoring buffers via excrete of H⁺ and reabsorbing HCO₃⁻, maintaining pH.

Studying That Suits You

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

Quiz Team

Related Documents

Water Balance PDF - Biology Past Paper

Description

This quiz explores the functions and regulatory mechanisms of antidiuretic hormone (ADH) within the endocrine system. Participants will learn about the triggers for ADH release, the role of osmoreceptors, and the impact of ADH on urine concentration. Test your knowledge on how the body maintains fluid balance through this vital hormone.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser