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Observe the solutions A & B!
Compare the colour!
Compare the volume!
Compare the smell!
Compare the temperature!
(op...
Subject X
Urine collect from
this boy an hour
after he drank 1
litre of water.
Subject Y
Urine collected
from this energetic
boy who did not
drink any water for
the past 5 hours.
Which sample belongs to
subject X?
 Which sample belongs to
subject Y?
Why???
Chapter 11
Part 1Excretion in
Humans
define excretion and explain the
importance of removing wastes
from the body.
to identify and state the functions
of dif...
• Removal of metabolic wastes &
toxic materials
• Metabolism = all the chemical
activities in living cells
Metabolism = Ca...
 Chemical processes that cause the
breakdown of complex substances
into simpler ones
 Examples:
1) Aerobic or anaerobic ...
 Chemical processes that form
complex substances from simpler
ones
 Examples:
1) Photosynthesis
2) Conversion of glucose...
 Excreted substances are:
 Carbon dioxide?
 Can change the pH level of blood plasma
 Water?
 Can change the water pot...
Excretory product Excretory organ
Carbon dioxide
Lungs  excreted
during exhalation
Urea Kidneys 
excreted in the
form of...
CENSORED
 A pair of dark red, bean-
shaped organs
 They are attached to the
dorsal body wall, one on
each side of the spinal
cord...
a) Ureter:
– A narrow tube
carrying urine
from the kidneys
to the bladder
– By peristalsis
b) Renal Pelvis:
– The enlarged...
c) Urinary Bladder:
A hollow muscular bag
used to store urine
temporarily
d) Sphincter muscles:
Relaxes to allow urine
to ...
 Each kidney is covered by
an outer layer of
protective cells called the
capsule
 It has 2 main regions:
 Medulla
 Cor...
 Medulla
 the inner region
 In man, it is split into
12 -16 conical
structures, called the
pyramids
 Cortex
 the oute...
 The functional unit of the
kidney
 Part of it is located in the
medulla, part of it is located
in the cortex
 Urine is...
• The renal artery brings
blood from the body into
the kidneys.
• It branches into
numerous afferent
arterioles.
• Each ar...
• This mass of
blood capillaries
is called the
glomerulus.
Glomerulus
+
Renal Capsule
Malpighian (Renal)
Corpuscle
• Blood leaves the
glomerulus through
the efferent arteriole
and enters blood
capillaries
surrounding the
tubule.
• These ...
 Small
substances are
forced under
high pressure
from the
glomerulus into
the renal capsule
Ultrafiltration
occurs here
 The renal capsule
leads into the
Proximal
Convoluted
Tubule
Selective reabsorption
occurs here
 The proximal
convoluted tubule
straightens out as
it passes into the
medulla, makes a
U-turn & passes
back into the
cort...
 Distal Convoluted
Tubule: The tubule
then becomes coiled
again
Selective reabsorption
continues here
 It then leads into a
Collecting Duct and
eventually leads into
the renal pelvis
Selective reabsorption
continues here
Time for activity!
Different in diameter
Afferent has a bigger
diameter than efferent
So what???
Topic 8: Chapter 11
Part 2
Excretion
Excretion
Waste Products removed by the Kidneys
Excess
Mineral Salts
Nitrogenous waste
• Mainly urea
• Creatinine
• Uric a...
Right Kidney Left
Kidney
Sphincter
Muscle
Inferior Vena
Cava
Dorsal Aorta
Renal Artery
Renal Vein
Ureter
Ureter
Urinary Bl...
Role of the Kidney
Carry out High Pressure Filtration of the blood to
achieve 2 functions
Removal of Urea
and toxins from
...
Renal Cortex
Medulla
The Right Kidney
The Nephron
Proximal
Convoluted Tubule
Descending Limb of
Loop of Henle
Ascending Limb of
Loop of Henle
Distal Convoluted
...
Ultrafiltration
Forced out of blood into kidney tubules Remains in the blood
Water RBC
Platelets
Blood Proteins (e.g Fibri...
Diffusion and
Active transport of
•Ions (Na+, Cl-)
•Amino Acids
•Glucose
Back into the
bloodstream
1
Water potential
gradi...
Flows through
Ureter
Urinary Bladder
Bladder wall is stretched
Bladder muscle will contract
Urine from the urinary bladder...
Topic 8: Chapter 11
Part 3
Excretion
• Maintenance of a constant water potential
in the body
• by regulating the water and solute levels
in the blood
• This is...
Absence of osmoregulation - Effects
• Blood plasma water potential will be higher than the surrounding
cells and tissues
•...
Kidneys as osmoregulators
1) Hypothalamus
• Control centre in the brain which controls body activities (e.g
temperature re...
The pituitary gland
Negative
feedback
mechanis
m
1) Blood Plasma •volume drops
• water potential decreases
• volume increases
• water potentia...
• Sodium chloride concentration in the blood
plasma also has an effect on the water potential
of the blood plasma.
• If so...
Kidneys controlling blood
pressure
Blood Volume Diameter of blood vessels
High blood pressure High Narrow
Low blood pressu...
Topic 8: Chapter 11
Part 4Excretion
- Partially -Permeable
- Allows small molecules
to pass:
• Water
• Sugars
• Salts
• Amino acids
• Urea
- Long and coiled t...
Difference in the concentration between the blood and dialysis fluid
Results in
Blood is purified
Therefore
Blood is drawn...
Difference between the Dialysis Machine and the Nephron
Dialysis Machine Nephron
Filtration does not take place Ultrafiltr...
Name: …………………………… ( ) Class: ……… Date: ……….………
Diagram of a Kidney
Diagram of a Kidney Tubule (Nephron)
Renal Cortex
Medulla
The Right Kidney
Topic 11 Excretion
Topic 11 Excretion
Topic 11 Excretion
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Topic 11 Excretion

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Topic 11 Excretion

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Topic 11 Excretion

  1. 1. Observe the solutions A & B! Compare the colour! Compare the volume! Compare the smell! Compare the temperature! (optional) Compare the texture! (optional) Compare the taste!
  2. 2. Subject X Urine collect from this boy an hour after he drank 1 litre of water.
  3. 3. Subject Y Urine collected from this energetic boy who did not drink any water for the past 5 hours.
  4. 4. Which sample belongs to subject X?  Which sample belongs to subject Y? Why???
  5. 5. Chapter 11 Part 1Excretion in Humans
  6. 6. define excretion and explain the importance of removing wastes from the body. to identify and state the functions of different parts of the urinary system.
  7. 7. • Removal of metabolic wastes & toxic materials • Metabolism = all the chemical activities in living cells Metabolism = Catabolism + Anabolism
  8. 8.  Chemical processes that cause the breakdown of complex substances into simpler ones  Examples: 1) Aerobic or anaerobic respiration 2) Deamination of proteins and excess amino acids in the liver to form urea. 3) Digestion of food substances
  9. 9.  Chemical processes that form complex substances from simpler ones  Examples: 1) Photosynthesis 2) Conversion of glucose into glycogen or starch 3) Synthesis of new cells
  10. 10.  Excreted substances are:  Carbon dioxide?  Can change the pH level of blood plasma  Water?  Can change the water potential in the blood plasma  Urea?  Can be toxic if accumulated to high amounts  Not useful to the body, excrete!
  11. 11. Excretory product Excretory organ Carbon dioxide Lungs  excreted during exhalation Urea Kidneys  excreted in the form of urineExcess water
  12. 12. CENSORED
  13. 13.  A pair of dark red, bean- shaped organs  They are attached to the dorsal body wall, one on each side of the spinal cord  The left kidney is slightly higher than the right one (Why ley?)
  14. 14. a) Ureter: – A narrow tube carrying urine from the kidneys to the bladder – By peristalsis b) Renal Pelvis: – The enlarged portion of the ureter inside the kidney
  15. 15. c) Urinary Bladder: A hollow muscular bag used to store urine temporarily d) Sphincter muscles: Relaxes to allow urine to flow from the bladder to the urethra e) Urethra: A tube which carries urine out of body
  16. 16.  Each kidney is covered by an outer layer of protective cells called the capsule  It has 2 main regions:  Medulla  Cortex
  17. 17.  Medulla  the inner region  In man, it is split into 12 -16 conical structures, called the pyramids  Cortex  the outer region
  18. 18.  The functional unit of the kidney  Part of it is located in the medulla, part of it is located in the cortex  Urine is formed in the nephron  About 1 million in each kidney  Each is about 3 cm in length  Total length: about 60 km
  19. 19. • The renal artery brings blood from the body into the kidneys. • It branches into numerous afferent arterioles. • Each arteriole branches into a mass of blood capillaries in the renal capsule Blood from the body
  20. 20. • This mass of blood capillaries is called the glomerulus. Glomerulus + Renal Capsule Malpighian (Renal) Corpuscle
  21. 21. • Blood leaves the glomerulus through the efferent arteriole and enters blood capillaries surrounding the tubule. • These blood capillaries then unite to form the renal vein Blood leaves the kidneys
  22. 22.  Small substances are forced under high pressure from the glomerulus into the renal capsule Ultrafiltration occurs here
  23. 23.  The renal capsule leads into the Proximal Convoluted Tubule Selective reabsorption occurs here
  24. 24.  The proximal convoluted tubule straightens out as it passes into the medulla, makes a U-turn & passes back into the cortex Selective reabsorption continues here
  25. 25.  Distal Convoluted Tubule: The tubule then becomes coiled again Selective reabsorption continues here
  26. 26.  It then leads into a Collecting Duct and eventually leads into the renal pelvis Selective reabsorption continues here
  27. 27. Time for activity!
  28. 28. Different in diameter Afferent has a bigger diameter than efferent So what???
  29. 29. Topic 8: Chapter 11 Part 2 Excretion
  30. 30. Excretion Waste Products removed by the Kidneys Excess Mineral Salts Nitrogenous waste • Mainly urea • Creatinine • Uric acid Excess H2O
  31. 31. Right Kidney Left Kidney Sphincter Muscle Inferior Vena Cava Dorsal Aorta Renal Artery Renal Vein Ureter Ureter Urinary Bladder Urethra
  32. 32. Role of the Kidney Carry out High Pressure Filtration of the blood to achieve 2 functions Removal of Urea and toxins from the blood Osmoregulation Maintain a constant blood plasma concentration
  33. 33. Renal Cortex Medulla The Right Kidney
  34. 34. The Nephron Proximal Convoluted Tubule Descending Limb of Loop of Henle Ascending Limb of Loop of Henle Distal Convoluted Tubule Bowman’s Capsule Glomerulus Collecting Duct Blood Capillaries
  35. 35. Ultrafiltration Forced out of blood into kidney tubules Remains in the blood Water RBC Platelets Blood Proteins (e.g Fibrinogen) Small Solute Molecules • Glucose • Amino Acids • Nitrogenous waste products (especially Urea) • Mineral Salts 2 conditions required: 1) High Blood Pressure – Afferent arteriole has a larger diameter than the efferent arteriole 2) Partially permeable membrane – Basement membrane of glomerulus has small pores that allows only water and small molecules to pass through
  36. 36. Diffusion and Active transport of •Ions (Na+, Cl-) •Amino Acids •Glucose Back into the bloodstream 1 Water potential gradient created H2O flows out of tubule into the blood capillaries by Osmosis 2 * Descending Limb is impermeable to Na+ and Cl- ions As the filtrate moves through the Distal tubule and down the Collecting Duct, more H2O is reabsorbed from the filtrate by Osmosis * Ascending Limb is impermeable H2O 4 Na+ and Cl- ions leaves the Ascending Limb into the interstitial fluid and is reabsorbed into the bloodstream by Diffusion & Active Transport Proximal Convoluted Tubule Proximal Convoluted Tubule + Descending Loop of Henle Distal convoluted Tubule + Collecting Duct Ascending Limb + Distal Convoluted Tubule Selective Reabsorption 3 Interstitial Fluid 2 1 H2O H2O H2O H2O Na+ Cl- 3 H2O H2O H2O H2O H2O H2O 4 Urine to Ureter H2O Na+ Cl-
  37. 37. Flows through Ureter Urinary Bladder Bladder wall is stretched Bladder muscle will contract Urine from the urinary bladder flows into the urethra To the Urine flows out of the body Urine Urea + Other nitrogenous waste (Creatinine, uric acid) + Excess Salts and ions + Excess water
  38. 38. Topic 8: Chapter 11 Part 3 Excretion
  39. 39. • Maintenance of a constant water potential in the body • by regulating the water and solute levels in the blood • This is an example of homeostasis (the maintenance of a constant internal environment)
  40. 40. Absence of osmoregulation - Effects • Blood plasma water potential will be higher than the surrounding cells and tissues • Water will enter the blood cells and surrounding tissue cells by osmosis • Cells will swell and burst Blood plasma too dilute Blood plasma too concentrated • Blood plasma water potential will be lower than the surrounding cells and tissues • Water will leave the blood cells and surrounding tissue cells by osmosis • Cells will shrink and crenate and be unable to perform its metabolic functions
  41. 41. Kidneys as osmoregulators 1) Hypothalamus • Control centre in the brain which controls body activities (e.g temperature regulation, blood plasma regulation and other involuntary responses in the body) 2) Pituitary gland • Releases hormones (e.g Antidiuretic Hormone) which are transported in the bloodstream to target organs to carry out its effect 3) Antidiuretic Hormones (ADH) • Increases water reabsorption by the kidney tubules back to the bloodstream • Causes vasoconstriction of arterioles Organs/Glands/Hormones involved in osmoregulation
  42. 42. The pituitary gland
  43. 43. Negative feedback mechanis m 1) Blood Plasma •volume drops • water potential decreases • volume increases • water potential increases Stimulus 2) Receptors in the Hypothalamus Are triggered Are triggered Receptor 3) Pituitary Gland Releases more ADH Releases less ADH Corrective mechanisms which brings about a response 4) Distal Convoluted Tubule and Collecting Duct More permeable to water Less permeable to water 5) Effect: More water reabsorbed back to the bloodstream Less water reabsorbed back to the bloodstream 6) Urine •Becomes more concentrated • Volume decreases • Becomes more dilute • Volume increases Effect 7) Blood Plasma • Volume increases • Water potential increases • Volume decreases • Water potential decreases Water potential returns to normal • Hypothalamus detects the normal blood plasma water potential and decreases the release of ADH by the pituitary gland. • Hypothalamus detects the normal blood plasma water potential and increases the release of ADH by the pituitary gland back to the normal level. Negative feedback to resume normal activity of pituitary gland Water lost through sweat Water gained through drinking
  44. 44. • Sodium chloride concentration in the blood plasma also has an effect on the water potential of the blood plasma. • If sodium chloride content in the blood plasma is high, • Sodium and chloride ion re-absorption from the glomerular filtrate back to the bloodstream will be reduced.
  45. 45. Kidneys controlling blood pressure Blood Volume Diameter of blood vessels High blood pressure High Narrow Low blood pressure Low Wide How are the kidneys involved in the treatment of high blood pressure? • By the prescription of “Diuretics” • Reduces the reabsorption of water from the distal convoluted tubule and collecting duct back to the blood capillaries • Blood volume decreases, Urine volume increases • Blood pressure decreases
  46. 46. Topic 8: Chapter 11 Part 4Excretion
  47. 47. - Partially -Permeable - Allows small molecules to pass: • Water • Sugars • Salts • Amino acids • Urea - Long and coiled to increase SA to VR for exchange of substances Consists of: Purpose: • H2O at a preset temperature To maintain an environment as close to the body as possible •Normal concentrations of essential substances as blood: (1)Glucose, (2)Mineral Ions, (3)Amino Acids - To ensure similar osmotic concentrations on both sides of tubing. (Minimize loss of water and essential substances from blood) •Blood and Dialysis Fluid flow in opposite directions - To create and maintain a diffusion gradient •Anti Coagulant Prevent blood from clotting The Dialysis Machine Pump Dialysis Tube Dialysis Fluid Pum p • Smoothen the blood flow • Maintain blood pressure • Maintain speed of blood flow
  48. 48. Difference in the concentration between the blood and dialysis fluid Results in Blood is purified Therefore Blood is drawn from an artery in the patient’s arm • Diffusion of urea and waste products down a concentration gradient • Diffusion of excess mineral down a concentration gradient • Movement of excess water out of blood by osmosis • Diffusion of essential mineral salts if lacking in blood Blood to Dialysate Dialysate to Blood Blood is returned to a vein in the patient’s arm
  49. 49. Difference between the Dialysis Machine and the Nephron Dialysis Machine Nephron Filtration does not take place Ultrafiltration occurs at the Bowman’s Capsule The pump keeps the blood pressure constant throughout the tubing Blood is under great pressure No active transport of solutes Active transport of solutes at the proximal and distal convoluted tubule, and loop of Henle. Depends largely on diffusion Depends largely on active transport and osmosis. Minimal diffusion
  50. 50. Name: …………………………… ( ) Class: ……… Date: ……….……… Diagram of a Kidney
  51. 51. Diagram of a Kidney Tubule (Nephron)
  52. 52. Renal Cortex Medulla The Right Kidney

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