Introduction to Excretion in Animals
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 is the primary function of the counter current flow between the descending and ascending limbs of the vasa recta?

  • To facilitate the return of filtrate back to the bloodstream
  • To dilute the urine produced by the kidneys
  • To create a counter current exchange that maintains a strong osmolarity gradient (correct)
  • To enhance the transport of electrolytes into the nephron

How does the osmolarity in the inner medulla compare to that in the cortex?

  • It remains the same as in the cortex
  • It is lower in the inner medulla compared to the cortex
  • It is significantly diluted compared to the cortex
  • It increases to approximately 1200 mOsmol/L (correct)

What substance is actively transported by the ascending limb of Henle's loop?

  • NaCl (correct)
  • Glucose
  • Urea
  • Water

How does the descending limb of Henle's loop affect the filtrate?

<p>It increases the concentration of the filtrate by allowing water to pass (C)</p> Signup and view all the answers

What is the result of the counter current mechanism established by the Henle's loop and vasa recta?

<p>It enables the kidneys to produce urine that is highly concentrated (A)</p> Signup and view all the answers

Which substance is the most toxic and requires large amounts of water for elimination?

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

What is the primary form of excretion in mammals?

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

What type of excretory structure is primarily responsible for removing nitrogenous wastes in earthworms?

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

Which of the following excretory products is least toxic and excreted in solid form?

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

Where are the kidneys located in the human body?

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

What is the main function of Malpighian tubules found in insects?

<p>Removing nitrogenous wastes (A)</p> Signup and view all the answers

Which excretory product is known to conserve water most effectively?

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

What type of excretion is characteristic of many bony fishes and aquatic amphibians?

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

What initiates the contraction of smooth muscles in the bladder?

<p>Motor messages from the CNS (A)</p> Signup and view all the answers

What is the primary function of the lungs in the excretion process?

<p>Removal of carbon dioxide (B)</p> Signup and view all the answers

Which component is NOT typically found in urine?

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

What is the average daily excretion of urine for an adult human?

<p>1 to 1.5 liters (A)</p> Signup and view all the answers

What is the term for the neural mechanism that triggers urine release?

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

Which of the following is a secondary function of sweat?

<p>Elimination of urea (D)</p> Signup and view all the answers

What is the pH level of urine typically considered to be?

<p>Slightly acidic at 6.0 (B)</p> Signup and view all the answers

Which substance is indicative of diabetes mellitus when found in urine?

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

What is one of the primary functions of sebum produced by sebaceous glands?

<p>To provide an oily covering for the skin (B)</p> Signup and view all the answers

Which treatment is used to manage uremia resulting from kidney failure?

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

What does kidney transplantation involve?

<p>Transferring a functioning kidney from a healthy donor (C)</p> Signup and view all the answers

What condition is characterized by the formation of stones of crystallized salts in the kidneys?

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

What is a common treatment option for managing renal calculi, depending on their size?

<p>Dietary changes or surgical removal (A)</p> Signup and view all the answers

Which condition involves inflammation of the glomeruli in the kidneys?

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

What type of fluid is used in hemodialysis for clearing waste from the blood?

<p>Dialysing fluid without nitrogenous wastes (A)</p> Signup and view all the answers

What can small amounts of nitrogenous wastes be excreted through?

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

What structure serves as a broad funnel-shaped space inside the hilum of the kidney?

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

Which part of the nephron is responsible for the initial filtration of blood?

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

What is the primary function of the proximal convoluted tubule (PCT)?

<p>Reabsorption of water and solutes (D)</p> Signup and view all the answers

Which type of nephron has a long loop of Henle that extends deep into the medulla?

<p>Juxta Medullary Nephrons (A)</p> Signup and view all the answers

What structure is the initial site for the collection of urine from several nephrons?

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

What is the function of the peritubular capillaries?

<p>To absorb nutrients and water from the filtrate (A)</p> Signup and view all the answers

What distinguishes cortical nephrons from juxta medullary nephrons?

<p>Length of the loop of Henle (C)</p> Signup and view all the answers

What anatomical feature surrounds the hilum of the kidney?

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

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

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

How does the juxtaglomerular apparatus (JGA) respond to a decrease in glomerular blood flow?

<p>Triggers renin release (B)</p> Signup and view all the answers

What is the effect of angiotensin II in the kidney?

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

What is the primary effect of atrial natriuretic factor (ANF)?

<p>Reduces blood vessel dilation (A)</p> Signup and view all the answers

Which physiological change triggers the release of ADH?

<p>Increased fluid loss (A)</p> Signup and view all the answers

What initiates the micturition reflex?

<p>Activation of stretch receptors in the bladder (C)</p> Signup and view all the answers

What is the result of increased aldosterone secretion?

<p>Enhanced sodium and water reabsorption (C)</p> Signup and view all the answers

What characteristic of urine is affected by the gradient in the collecting tubule?

<p>Concentration of solutes (D)</p> Signup and view all the answers

What is one of the main effects of ADH on blood vessels?

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

How does atrial natriuretic factor (ANF) influence kidney filtration?

<p>Suppresses renin release (B), Inhibits water reabsorption (D)</p> Signup and view all the answers

Flashcards

Kidney Dimensions

Length: 10-12 cm, Width: 5-7 cm, Thickness: 2-3 cm, Weight: 120-170 g.

Hilum

A notch on the kidney's inner surface where vessels and ureter enter.

Nephron

A tiny filtering unit within the kidney, functionally critical.

Bowman's Capsule

A cup-shaped structure surrounding the glomerulus.

Signup and view all the flashcards

Glomerulus

A tuft of capillaries where filtration begins.

Signup and view all the flashcards

Renal Tubule

A series of tubules that process filtered fluid.

Signup and view all the flashcards

Cortical Nephrons

Nephrons with short loops of Henle.

Signup and view all the flashcards

Juxtamedullary Nephrons

Nephrons with long loops of Henle.

Signup and view all the flashcards

Ammonotelism

The excretion of ammonia, a very toxic waste product. This method requires large amounts of water for elimination.

Signup and view all the flashcards

Ureotelism

The excretion of urea, a less toxic waste product than ammonia, requiring less water for elimination.

Signup and view all the flashcards

Uricotelism

The excretion of uric acid, the least toxic waste product, which conserves water and is excreted in a solid form.

Signup and view all the flashcards

Protonephridia (Flame Cells)

Excretory structures found in some invertebrates, functioning primarily in ion and fluid regulation.

Signup and view all the flashcards

Nephridia

Excretory structures in worms responsible for removing nitrogenous wastes, adjusting body fluid, and ionic balance.

Signup and view all the flashcards

Malpighian Tubules

Excretory structures in insects, removing metabolic wastes and regulating osmolarity.

Signup and view all the flashcards

Kidney Shape

Bean-shaped and reddish-brown in color in mammals.

Signup and view all the flashcards

Kidney Location

Located between the back ribs and lower spine, near the backbone inside the abdominal cavity.

Signup and view all the flashcards

Countercurrent Mechanism

The process where blood flows in opposite directions in the descending and ascending limbs of the vasa recta and Henle's loop, creating a concentration gradient in the medulla.

Signup and view all the flashcards

Osmolarity Gradient in Medulla

The concentration of solutes in the medullary interstitium increases from the cortex (around 300 mOsmol/L) to the inner medulla (around 1200 mOsmol/L).

Signup and view all the flashcards

Role of NaCl in Concentration

NaCl is actively transported out of the ascending limb of Henle's loop, creating a concentration gradient. It is then exchanged with the descending limb of vasa recta and returned to the interstitium by the ascending limb.

Signup and view all the flashcards

Urea's Role in Concentration

Urea enters the thin segment of the ascending limb of Henle's loop and is transported back to the interstitium by the collecting tubule, contributing to the concentration gradient.

Signup and view all the flashcards

How is concentrated urine produced?

The countercurrent mechanism established by Henle's loop and vasa recta allows the kidney to produce urine that is nearly four times more concentrated than the initial filtrate.

Signup and view all the flashcards

Stretch Receptors in Bladder

These receptors on the bladder wall signal the CNS when the bladder stretches, triggering urination.

Signup and view all the flashcards

CNS Response to Bladder Stretch

The CNS receives signals from stretch receptors and initiates bladder contraction and sphincter relaxation for urine release.

Signup and view all the flashcards

Micturition Process

This includes bladder muscle contraction, urethral sphincter relaxation, and urine release, controlled by the micturition reflex.

Signup and view all the flashcards

Urine Characteristics

Normally, urine is a watery, yellow fluid with a slightly acidic pH and a characteristic odor, containing urea.

Signup and view all the flashcards

Urine Analysis

Examining urine can help diagnose metabolic disorders and kidney problems by detecting substances like glucose or ketones.

Signup and view all the flashcards

Lungs in Excretion

The lungs mainly remove carbon dioxide but also eliminate significant amounts of water vapor.

Signup and view all the flashcards

Liver's Role in Excretion

This largest gland processes and excretes bilirubin, cholesterol, hormones, vitamins, and drugs in bile.

Signup and view all the flashcards

Skin in Excretion

Sweat glands release watery sweat containing salts and waste products, helping cool the body and eliminate waste.

Signup and view all the flashcards

What is the role of the gradient in urine concentration?

The gradient in the kidney helps to concentrate urine by allowing water to move from the collecting tubule back into the blood, making the urine more concentrated.

Signup and view all the flashcards

How does ADH affect kidney function?

Antidiuretic hormone (ADH) increases water reabsorption from the collecting tubule, leading to less urine output and more concentrated urine. It also constricts blood vessels, increasing blood pressure and glomerular filtration rate (GFR).

Signup and view all the flashcards

What stimulates the release of ADH?

ADH release is triggered by an increase in blood osmolarity, a decrease in blood volume, or a decrease in body fluid volume. These changes signal a need for water conservation.

Signup and view all the flashcards

What is the function of the Juxtaglomerular Apparatus (JGA)?

The JGA functions as a sensor, monitoring blood flow, pressure, and GFR. It releases renin in response to a decrease in these factors.

Signup and view all the flashcards

How does the Renin-Angiotensin-Aldosterone System (RAAS) work?

Renin released from the JGA converts angiotensinogen into angiotensin I, which is then converted to angiotensin II. Angiotensin II constricts blood vessels and stimulates aldosterone release from the adrenal cortex. Aldosterone increases sodium and water reabsorption in the distal tubules, increasing blood volume and GFR.

Signup and view all the flashcards

How does Atrial Natriuretic Factor (ANF) regulate kidney function?

ANF is released from the heart atria in response to increased blood volume and pressure. It dilates blood vessels, decreasing blood pressure and counteracting the RAAS system, ultimately reducing GFR.

Signup and view all the flashcards

What triggers the micturition reflex?

Micturition, or urination, is initiated by stretching of the urinary bladder as it fills with urine.

Signup and view all the flashcards

What happens during the micturition reflex?

The bladder stretches, signaling the spinal cord and brainstem, which triggers muscle contractions in the bladder wall and relaxation of the urethral sphincter, allowing urine to pass out of the body.

Signup and view all the flashcards

How does urine concentration relate to water conservation?

Concentrated urine indicates efficient water reabsorption, which is essential for conserving water in the body.

Signup and view all the flashcards

What is the importance of kidney function regulation in maintaining homeostasis?

Regulation of kidney function plays a crucial role in maintaining fluid balance, blood pressure, and electrolyte levels, ensuring proper body function.

Signup and view all the flashcards

Sebum Function

Sebum is an oily substance secreted by sebaceous glands that provides a protective layer for the skin and aids in the excretion of certain substances.

Signup and view all the flashcards

What role does saliva play in excretion?

Saliva plays a minor role in excretion, eliminating small amounts of nitrogenous wastes.

Signup and view all the flashcards

Uremia

Uremia is a condition where urea, a nitrogenous waste product, accumulates in the blood due to kidney malfunction. This can lead to kidney failure and be highly harmful to the body.

Signup and view all the flashcards

Hemodialysis

Hemodialysis is a treatment for kidney failure where blood is filtered through an artificial kidney, known as a dialysis machine.

Signup and view all the flashcards

Kidney Transplantation

A kidney transplant involves replacing a non-functional kidney with a healthy one from a donor, usually a close relative.

Signup and view all the flashcards

Renal Calculi

Renal calculi, or kidney stones, are hardened masses of crystallized salts (like oxalates) that form within the kidneys.

Signup and view all the flashcards

Glomerulonephritis

Glomerulonephritis is inflammation of the glomeruli, the tiny filtering units within the kidneys, which can lead to impaired kidney function.

Signup and view all the flashcards

Treating Glomerulonephritis

Treating glomerulonephritis involves addressing the underlying cause, utilizing anti-inflammatory medications, and other medical interventions.

Signup and view all the flashcards

Study Notes

Introduction to Excretion

  • Animals accumulate substances like ammonia, urea, uric acid, carbon dioxide, water, and various ions through metabolic activities.
  • These substances need to be removed.

Types of Excretory Products

  • Ammonia: Highly toxic, requires a large amount of water for elimination.
  • Urea: Less toxic than ammonia, conserves water.
  • Uric Acid: Least toxic, minimal water loss, excreted as a solid.

Mechanisms of Excretion

  • Ammonotelism: Excretion of ammonia, common in bony fish, aquatic amphibians, and aquatic insects. Ammonia diffuses across body surfaces or gills.
  • Ureotelism: Excretion of urea, common in mammals and many amphibians, and marine fish. Ammonia is converted into urea in the liver and excreted by the kidneys.
  • Uricotelism: Excretion of uric acid, common in reptiles, birds, land snails, and insects. Uric acid is excreted in a pellet or paste form, conserving water.

Excretory Structures in Animals

  • Invertebrates:
    • Protonephridia (flame cells): Found in Platyhelminthes (e.g., planaria), rotifers, some annelids, and cephalochordates. Regulate ionic and fluid volume.
    • Nephridia: Found in earthworms and other annelids. Remove nitrogenous wastes and regulate fluid and ionic balance.
    • Malpighian tubules: Found in insects, including cockroaches, responsible for nitrogenous waste removal and osmoregulation.
    • Antennal glands (green glands): Found in crustaceans; involved in excretion.

Human Excretory System

  • Components: Kidneys, ureters, urinary bladder, and urethra.
  • Kidney Shape & Color: Reddish-brown, bean-shaped.
  • Kidney Location: Between the last thoracic and third lumbar vertebrae, close to the dorsal inner wall of the abdominal cavity.
  • Kidney Dimensions: 10-12 cm long, 5-7 cm wide, 2-3 cm thick, weighing 120-170g.
  • Hilum: Notch on the inner concave surface where ureter, blood vessels, and nerves enter.
  • Renal Pelvis: Funnel-shaped space inside the hilum with projections called calyces.
  • Outer Layer: Tough capsule covering the kidney.

Kidney Zones and Nephrons

  • Medullary Pyramids: Conical masses in the medulla, projecting into the calyces.

  • Renal Columns: Cortex extending between the medullary pyramids.

  • Nephrons: Nearly one million complex tubular structures, functional units of kidneys.

  • Nephron Parts: glomerulus, Bowman's capsule, PCT, loop of Henle, DCT, collecting duct.

    • Glomerulus: A tuft of capillaries formed by the afferent arteriole, filtering blood.
    • Bowman's Capsule: A double-walled cup-like structure surrounding the glomerulus.
    • Malpighian Body: Combined structure of the glomerulus and Bowman's capsule.
    • Proximal Convoluted Tubule (PCT): Coiled network following Bowman's capsule.

  • Henle's Loop: Hairpin-shaped structure with descending and ascending limbs.

  • Distal Convoluted Tubule (DCT): Coiled region following the ascending limb of the loop of Henle.

  • Collecting Duct: The DCTs of many nephrons converge, opening into the renal pelvis through medullary pyramids.

  • Types of Nephrons: Cortical and juxtamedullary, distinguished by loop of Henle length.

Urine Formation

  • Glomerular Filtration: Filtration of blood through three layers (endothelium, basement membrane, epithelium of Bowman's capsule) creating filtrate.
  • Reabsorption: Selective reabsorption of essential nutrients and electrolytes from the filtrate back into the blood.
  • Tubular Secretion: Secretion of substances into the filtrate from the blood.

Regulation of Kidney Function

  • Hypothalamus & ADH (Vasopressin): Osmoreceptors regulate ADH release, controlling water reabsorption and urine concentration.
  • Juxtaglomerular Apparatus (JGA): Monitors blood flow, pressure, and GFR, regulating renin release.
  • Renin-Angiotensin Mechanism: Regulates blood pressure and GFR.
  • Atrial Natriuretic Factor (ANF): Released in response to increased blood flow, working against renin-angiotensin.

Micturition

  • Micturition reflex initiates actions that lead to urine release from the body.

Role of Other Organs in Excretion

  • Lungs: Main role is CO2 removal, also excrete water.
  • Liver: Processes and excretes substances like bilirubin, bile, cholesterol.
  • Skin: Sweat glands remove water, salts, and some waste products.

Diseases

  • Uremia: Accumulation of urea in the blood due to kidney failure.
  • Kidney Transplantation: Replacing a failed kidney with a healthy donated kidney.
  • Renal Calculi (Kidney Stones): Formation of stones in the kidney.
  • Glomerulonephritis: Inflammation of the glomeruli.

Studying That Suits You

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

Quiz Team

Related Documents

Excretion PDF

Description

Explore the processes and types of excretion in animals, including ammonia, urea, and uric acid. Understand the mechanisms like ammonotelism, ureotelism, and uricotelism, along with the structures involved in excretion. This quiz will test your knowledge on how different organisms manage waste removal.

More Like This

Animal Excretion Mechanisms
4 questions

Animal Excretion Mechanisms

FlawlessPeridot avatar
FlawlessPeridot
Excretion in Animals Quiz
8 questions

Excretion in Animals Quiz

InterestingCottonPlant avatar
InterestingCottonPlant
Excreción en Animales
5 questions

Excreción en Animales

PerfectArtNouveau9312 avatar
PerfectArtNouveau9312
Excretion in Animals
8 questions

Excretion in Animals

AccurateOnomatopoeia1292 avatar
AccurateOnomatopoeia1292
Use Quizgecko on...
Browser
Open
Browser
Browser