1. Homeostasis: The kidney
Learning Objectives:
To know the role of the kidney
To be able to label a diagram of the human excretory system
To be able to label a section through the kidney and a nephron
To understand the role of ADH and interpret data about the presence of substances during the passage through the kidney

2. What is the job of the urinary system?
To regulate the volume and composition of body fluids, removing waste products from the body and expelling the waste and excess water from the body in the form of urine.

3. The kidney
Your kidneys remove the poisonous substances which your cells produce. Our bodies break down the protein in our food into amino acids. The diagram shows what happens to these amino acids:
Amino acids in blood
Protein in your cells
Urea in your blood
Some are used for growth and repair
Some are not used – they are broken down in the liver

4. The main poison your kidneys remove
Urea is made in the liver from amino acids. Urea is a poisonous substance. Your kidneys remove it from your blood. They also remove excess salt (ions) from your blood. The urea and salts are dissolved in water to make a liquid called urine.

5. Interesting facts
The kidneys filter about 1.3 litres of blood a minute.
All the body’s blood flows through the kidneys every 10 minutes, so blood is filtered 150 times a day.

6. Excretory system
The renal vein carries cleaned blood away from the kidneys
The renal artery carries ‘dirty’ blood (with waste) into the kidneys
The kidneys remove urea and other waste
Ureters are tubes which carry urine to the bladder
The bladder is a bag that stores urine
The sphincter is a ring of muscle that keeps the bladder closed until you go to the toilet
The urethra is a tube which carries urine out of your body

7. Now see how much you remember… and click on his thoughts

8. The structure of the kidney
Medulla
Renal artery
Cortex
Nephron within the kidney
Renal vein
Ureter
Pelvis

9. Now see how much you remember this time… and click on her thoughts

10. The nephron Capillary knot Collecting duct Bowmans capsule
Capillary network
Tubule

11. The nephron The diagram below shows a flattened section of the nephron
‘Dirty blood’
Capillary
‘Cleaned blood’
Useful substances are reabsorbed into the blood
Urine goes to the bladder
Useful substances
Urine (urea and water)
Urine
Urine
Bowman’s Capsule
Tubule

12. The nephron ‘Dirty blood’ Capillary ‘Cleaned blood’
Blood is filtered through the capillary knot. Nearly all the blood except red cells filters through into the nephron
The liquid left in the nephron is urine. It contains urea and water and other unwanted substances. It then goes through the collecting duct and ureters to the bladder.
The liquid in the nephron contains useful substances like glucose and vitamins. These are then absorbed back into the blood (reabsorbed).
‘Dirty blood’
Capillary
‘Cleaned blood’
Useful substances are reabsorbed into the blood
Urine goes to the bladder
Useful substances
Urine (urea and water)
Urine
Urine
Bowman’s Capsule
Tubule

13. Postcard Wish you were here…
Complete the postcard to explain your journey through the excretory system. You are a water molecule travelling through the blood.
Wish you were here…
Dear Celia the Ciliated Epithelial Cell,
I have been on the most incredible journey! It all started when…
Celia
Ciliated Epithelial Cells
Front of Postcard
Back of Postcard
Urinary Tract

14. Role of anti-diuretic hormone
If there is too little water in your blood then the body detects this and the pituitary gland produces anti-diuretic hormone (ADH).
ADH increases the permeability of the tubules, and allows the kidneys to reabsorb more water, making a more concentrated urine.
The more ADH, the more concentrated the urine.

15. The kidneys and water control
Drag the boxes below to complete the table
Too much water in body
Too little water in body
Water in urine
Urine colour
Presence of ADH
A little
Yellow
More ADH
A lot
Colourless
Less ADH

16. Kidney graphs Volume of urine (ml) Salt concentration (ml)
Time after drinking (mins)
Time after drinking (mins)
normal level

17. Using the graphs answer the questions on the separate sheet

18. Research Task
Kidney failure can be treated by dialysis or by replacing it with a healthy one by transplant from a donor
Produce a leaflet for someone with a kidney problem, outlining the advantages and disadvantages of the use of dialysis or transplantation. Remember to use science to explain the procedures and remember to use more than 2 sources of information to improve the reliability.

19. What have we learnt? To know the role of the kidney
To be able to label a diagram of the human excretory system
To be able to label a section through the kidney and a nephron
To understand the role of ADH and interpret data about the presence of substances during the passage through the kidney
Learning outcomes

20. Use Prezi to produce a concept map of your learning for this topic
Click on the link to learn how to produce your own at home