Human Excretory System Quiz
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Questions and Answers

What is the average weight range of an adult human kidney?

  • 170-200 g
  • 120-170 g (correct)
  • 100-120 g
  • 200-250 g

What is the function of the renal pelvis in the kidney?

  • To produce hormones
  • To filter blood
  • To funnel urine into the ureter (correct)
  • To store nephrons

What structures project into the calyces of the kidney?

  • Nephrons
  • Renal columns
  • Medullary pyramids (correct)
  • Hilum

Which part of the nephron is referred to as the renal corpuscle?

<p>Glomerulus along with Bowman’s capsule (C)</p> Signup and view all the answers

What is the outer layer of the kidney known as?

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

What are the Columns of Bertini in the kidney?

<p>Cortical extensions between medullary pyramids (A)</p> Signup and view all the answers

What is the primary function of the glomerulus?

<p>To filter blood (C)</p> Signup and view all the answers

Which structure carries blood away from the glomerulus?

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

Which type of nitrogenous waste do uricotelic animals primarily excrete?

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

What are the excretory structures in Platyhelminthes known as?

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

Which of the following structures is responsible for excretion in crustaceans?

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

What is the primary role of nephridia in annelids?

<p>Nitrogenous waste removal and ionic balance (D)</p> Signup and view all the answers

Where are the kidneys located in humans?

<p>Between the last thoracic and third lumbar vertebrae (D)</p> Signup and view all the answers

Which structure is involved in fluid volume regulation in certain invertebrates?

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

What distinguishes complex kidneys in vertebrates from simpler excretory structures in invertebrates?

<p>Selective filtration processes (B)</p> Signup and view all the answers

What is the main function of Malpighian tubules in insects?

<p>Nitrogenous waste removal and osmoregulation (B)</p> Signup and view all the answers

What percentage of the filtrate is typically reabsorbed by the renal tubules?

<p>99% (C)</p> Signup and view all the answers

Which structure is primarily responsible for glomerular filtration?

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

What does a fall in the glomerular filtration rate (GFR) trigger?

<p>Release of renin (D)</p> Signup and view all the answers

What is the glomerular filtration rate (GFR) in a healthy individual?

<p>125 ml/minute (B)</p> Signup and view all the answers

Which type of nephron is associated with a reduced vasa recta?

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

The filtration slits in Bowman's capsule are formed by which type of cells?

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

What process is primarily responsible for removing substances from the nephron into the blood?

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

How much blood is filtered by the kidneys per minute on average?

<p>1100-1200 ml (A)</p> Signup and view all the answers

Which statement correctly describes the role of ADH in urine formation?

<p>ADH increases the concentration of urine by promoting water retention. (A)</p> Signup and view all the answers

What is the main function of the Bowman’s capsule in the nephron?

<p>To filter protein-free fluid from blood plasma. (D)</p> Signup and view all the answers

What do you understand by the term 'osmoregulation'?

<p>The regulation of water balance and solute concentration in the body. (B)</p> Signup and view all the answers

How does the loop of Henle contribute to urine concentration?

<p>By creating a countercurrent mechanism that enables solute reabsorption. (B)</p> Signup and view all the answers

What is micturition?

<p>The act of expelling urine from the bladder. (A)</p> Signup and view all the answers

What type of transport mechanism is primarily used for reabsorbing glucose and amino acids in the nephron?

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

Which statement about the Proximal Convoluted Tubule (PCT) is correct?

<p>It reabsorbs up to 70-80% of electrolytes and water. (A)</p> Signup and view all the answers

What is the primary function of the ascending limb of Henle's Loop?

<p>Reabsorbing Na+ and Cl- (C)</p> Signup and view all the answers

What substances are secreted into the filtrate by tubular secretion?

<p>Hydrogen ions and ammonia (B)</p> Signup and view all the answers

In which part of the nephron does conditional reabsorption of Na+ and water predominantly occur?

<p>Distal Convoluted Tubule (DCT) (D)</p> Signup and view all the answers

What characteristic of the descending limb of the Loop of Henle contributes to the concentration of the filtrate?

<p>It is permeable to water but not to electrolytes. (C)</p> Signup and view all the answers

How does the collecting duct contribute to urine formation?

<p>It reabsorbs large amounts of water to concentrate urine. (B)</p> Signup and view all the answers

What is a major function of the kidneys in relation to body fluids?

<p>Maintaining ionic and acid-base balance (B)</p> Signup and view all the answers

What role does antidiuretic hormone (ADH) play in kidney function?

<p>It facilitates water reabsorption in the kidney tubules. (B)</p> Signup and view all the answers

How does angiotensin II influence kidney function?

<p>Increases glomerular blood pressure and GFR. (B)</p> Signup and view all the answers

What is the primary function of the juxtaglomerular apparatus (JGA) in kidney regulation?

<p>To release renin when glomerular pressure is low. (A)</p> Signup and view all the answers

What effect does Atrial Natriuretic Factor (ANF) have on blood pressure?

<p>It lowers blood pressure by causing vasodilation. (B)</p> Signup and view all the answers

Which mechanism acts as a check on the renin-angiotensin mechanism?

<p>The Atrial Natriuretic Factor (ANF). (C)</p> Signup and view all the answers

What initiates the signal for micturition?

<p>The stretching of the urinary bladder. (D)</p> Signup and view all the answers

When does the hypothalamus release antidiuretic hormone (ADH)?

<p>When there is an excessive loss of body fluid. (C)</p> Signup and view all the answers

What triggers the osmoreceptors in the body?

<p>Variations in blood volume and ionic concentration. (C)</p> Signup and view all the answers

Flashcards

Uricotelic animals

Animals that excrete nitrogenous waste as uric acid, which is in the form of a pellet or paste, minimizing water loss.

Protonephridia

Excretory structures in some invertebrates, like flatworms, that primarily regulate ions and fluid volume.

Nephridia

Tubular excretory structures in annelids (like earthworms) removing nitrogenous wastes and maintaining fluid balance.

Malpighian tubules

Excretory structures in insects, involved in removing nitrogenous wastes and osmoregulation.

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Antennal glands (green glands)

Excretory structures in crustaceans (like prawns) that perform excretory functions.

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Human excretory system

Consists of kidneys, ureters, urinary bladder, and urethra, responsible for waste removal.

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Kidneys

Bean-shaped organs located in the abdominal cavity, crucial for urine production and waste removal.

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Vasa Recta

Absent or highly reduced in cortical nephrons.

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Urine Formation

Involves glomerular filtration, reabsorption, and secretion in the nephron.

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Glomerular Filtration

First step of urine formation, filtering blood through the glomerulus.

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Glomerular Filtration Rate (GFR)

Amount of filtrate formed per minute by the kidneys (approx. 125 ml/minute).

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Juxtaglomerular Apparatus (JGA)

Special region sensitive to GFR changes, regulates it via renin release.

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Reabsorption

Process where nearly 99% of the filtrate is reabsorbed by renal tubules.

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Glomerular Capillary Blood Pressure

Driving force for filtration through the glomerulus.

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Podocytes

Specialized epithelial cells in Bowman's Capsule, form filtering slits/pores.

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Ultrafiltration

Filtration process allowing almost all plasma components except proteins to pass through.

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Renal Tubules

Structures within the kidney where reabsorption occurs.

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Kidney Dimensions

Adult human kidneys are typically 10-12 cm long, 5-7 cm wide, and 2-3 cm thick, weighing 120-170 grams.

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Kidney Hilum

A notch on the kidney's inner surface where structures like the ureter, blood vessels, and nerves enter and exit.

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Renal Pelvis

A funnel-shaped space inside the kidney, located near the hilum, with projections called calyces.

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Kidney Capsule

The tough, outer layer of the kidney that protects the internal structures.

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Kidney Cortex and Medulla

The kidney's inner and outer zones. The medulla contains conical masses (pyramids), while the cortex lies in between.

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Renal Columns

Extensions of the cortex between the medullary pyramids in the kidney.

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Nephrons

The functional units of the kidney, responsible for filtering blood and forming urine.

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Glomerulus

A tuft of capillaries in the nephron, where blood filtration begins.

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Afferent Arteriole

A blood vessel that brings blood to the glomerulus.

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Efferent Arteriole

A blood vessel that carries blood away from the glomerulus.

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Bowman's Capsule

A cup-shaped structure that surrounds the glomerulus, where filtration occurs.

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Malpighian Body/Renal Corpuscle

The structure formed by the glomerulus and Bowman's capsule.

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Kidney Function Regulation

Kidney function is controlled by hormones, primarily the hypothalamus, JGA, and heart.These adjust blood pressure and fluid balance.

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Antidiuretic Hormone (ADH)

A hormone that manages water reabsorption in the kidneys, reducing diuresis (excessive urine production).

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Renin-Angiotensin Mechanism

A complex system where renin triggers a cascade that leads to blood vessel constriction and increased blood pressure, ultimately regulating glomerular blood pressure and GFR.

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Atrial Natriuretic Factor (ANF)

A hormone that causes vasodilation and reduces blood pressure when blood volume increases, acting as a counter to the renin-angiotensin system.

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Micturition

The process of emptying the bladder through CNS control, triggered by the bladder's stretching due to urine.

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Juxtaglomerular Apparatus (JGA)

A structure in the kidneys that plays a crucial role in regulating blood pressure and glomerular filtration rate.It releases renin, thus affecting the renin-angiotensin system.

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Nephron Reabsorption

The process where the nephron reclaims essential substances from the filtrate and returns them to the bloodstream.

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Proximal Convoluted Tubule (PCT)

The first segment of the nephron, responsible for reabsorbing most nutrients and electrolytes.

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Brush border epithelium

Epithelial cells lining the PCT, greatly increasing surface area for reabsorption.

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Henle's Loop

A loop in the nephron that helps create a concentration gradient in the kidney.

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Descending limb of Henle's Loop

Permeable to water but impermeable to electrolytes, concentrating the filtrate as it moves down.

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Ascending limb of Henle's loop

Impermeable to water, actively or passively transporting electrolytes and diluting the filtrate.

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Distal Convoluted Tubule (DCT)

Reabsorbs sodium, water, and bicarbonate, secreting hydrogen and potassium ions for pH balance.

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Tubular Secretion

The process where the tubular cells actively secrete substances into the filtrate.

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Collecting Duct

A long duct collecting filtrate, reabsorbing water to produce concentrated urine.

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ADH and Urine Hypotonicity

Antidiuretic hormone (ADH) helps in water retention. This results in urine that is less concentrated (hypotonic).

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Filtration in Bowman's Capsule

Protein-free fluid from blood plasma is filtered into Bowman's capsule, the first step in urine formation.

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Henle's Loop Role

Henle's loop plays a crucial role in concentrating urine.

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Glucose Reabsorption

Glucose is actively reabsorbed in the proximal convoluted tubule.

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Countercurrent Mechanism

A mechanism in the kidney that concentrates urine by using opposing flows of fluids.

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Excretory Systems: Liver, Lungs, Skin

Liver, lungs, and skin are all involved in removing wastes and regulating things in the body.

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Micturition

The process of expelling urine from the bladder.

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Osmoregulation

The process of maintaining the right water and salt balance in the body.

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Ureotelic vs Ammonotelic

Terrestrial animals mostly rely on excreting urea or uric acid (ureotelic or uricotelic), rather than ammonia (ammonotelic) due to water conservation needs.

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JGA Role

The juxta glomerular apparatus (JGA) is a group of cells plays a key role in regulating blood pressure and glomerular filtration rate.

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Excretory Structures (Flame Cells)

Some chordates have flame cells for excretion.

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Medullary Pyramids

The parts of the kidney that contain urine-forming structures.

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Vasa Recta

A loop of capillaries running parallel to Henle's loop. Function is related to urine concentration.

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Ascending limb of Henle's loop permeability to water

The ascending limb is impermeable to water.

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Descending limb of Henle's loop permeability to water

The descending limb is permeable to water.

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ADH role in water reabsorption

The distal tubules facilitate water reabsorption when ADH is involved.

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Dialysis Fluid Composition

Dialysis fluid contains all the constituents except blood protein levels.

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Average Urea Excretion

A healthy adult human typically excretes about X grams of urea per day. (Value omitted from prompt).

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Study Notes

Human Excretory System

  • Animals accumulate various metabolic byproducts like ammonia, urea, uric acid, and ions.
  • These need to be eliminated partially or totally.
  • Ammonia is the most toxic nitrogenous waste and requires large amounts of water for elimination.
  • Uric acid is the least toxic and can be eliminated with minimal water loss.
  • Ammonotelism is the excretion of ammonia, common in aquatic bony fishes, aquatic amphibians, and aquatic insects.
  • Ureotelism describes the excretion of urea, predominant in mammals, many terrestrial amphibians, and marine fishes.
  • Uricotelism is the excretion of uric acid, common in reptiles, birds, land snails, and insects.

Urine Formation

  • Urine formation involves three processes: glomerular filtration, reabsorption, and secretion.
  • Glomerular filtration is the initial blood filtration process.
  • Reabsorption is the process of returning essential substances back into the bloodstream.
  • Secretion is the process of removing additional waste products from the blood and adding them to the filtrate.

Function of Tubules

  • Proximal Convoluted Tubule (PCT): Reabsorption of essential nutrients, electrolytes, and water, and pH regulation.
  • Henle's Loop: Plays a crucial role in maintaining high osmolarity of the medullary interstitial fluid, which contributes to urine concentration.
  • Distal Convoluted Tubule (DCT): Conditional reabsorption of sodium and water, and secretion of hydrogen and potassium ions, and regulation of pH.
  • Collecting Duct: Reabsorption of water and secretion of salts, contributing significantly to urine concentration.

Regulation of Kidney Function

  • Hormonal feedback mechanisms regulate kidney function.
  • Osmoreceptors in the body detect changes in blood volume, body fluids, and ionic concentration.
  • An increase in body fluid volume can trigger the release of ADH (Antidiuretic hormone or vasopressin).
  • ADH promotes water reabsorption, reducing urine output.
  • The juxtamedullary apparatus (JGA): Plays a key role in regulating glomerular filtration rate (GFR).
  • A fall in GFR can activate JGA cells to release renin, which triggers a series of events that increase GFR.
  • The renin–angiotensin mechanism: A complex system involving the release of renin, angiotensin, and aldosterone to regulate blood pressure and fluid balance.
  • Atrial natriuretic factor (ANF): Released in response to increased blood flow to the heart, ANF helps to reduce blood pressure.

Micturition

  • Urine is stored in the bladder until a voluntary signal stimulates bladder contraction and relaxation of the urethral sphincter.
  • Neural mechanisms in the CNS control micturition.
  • Stretch receptors in the bladder walls detect filling and send signals to the CNS.
  • The CNS sends signals back to the bladder and associated muscles to cause contraction and relaxation for urination.

Other Excretory Structures

  • Kidneys are primary excretory organs.
  • Lungs, liver, and skin also play important roles in excretion:
  • Lungs remove carbon dioxide and water.
  • Liver eliminates bile pigments and other substances.
  • Skin helps remove water, salts, and urea through sweat.
  • Malfunctioning of the kidneys can lead to a buildup of urea in the blood, a condition called uremia.
  • Hemodialysis is a procedure to remove waste from the blood when the kidneys fail.
  • Kidney transplantation: The ultimate method in treating acute renal failure, if a suitable donor is found.

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Chapter 16: Excretory Products and Their Elimination PDF

Description

Test your knowledge on the human excretory system, including the processes of urine formation and the types of nitrogenous waste. Learn about ammonotelism, ureotelism, and uricotelism, and how different animals manage their waste. This quiz will challenge your understanding of how the body eliminates metabolic byproducts.

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