1. Animal Survival
Water and Waste

2. G1: Identify the ways in which a mammal gains and loses water
Water Loss
Urine (Urea in water)
Faeces
Sweat
Breathing
Water Gain
Food
Drink
Chemical Reactions*
*Respiration = how the body releases energy from food.
Oxygen + Food  Carbon Dioxide + Water + Energy

3. The kidneys make sure that the amount of water gain equals the amount of water loss
Water Balance
Water In = Water Out

4. G2: State that the kidneys are the main organs for regulating the water content in a mammal.
This is called
OSMOREGULATION
water
regulate/control
G3: Identify the position and state the functions of the kidney, renal arteries, renal veins, ureter and bladder.

5. Name
Function
Kidney
Filter blood. Remove excess water and urea
Renal Arteries
Supply blood to the kidneys
Renal Vein
Take filtered blood away from the kidneys
Ureter
Take urine (urea and water) from the kidneys to the bladder
Bladder
Stores urine until it is passed out of the body

6. G4: State that the kidneys work by filtration of blood and reabsorption of useful materials such as glucose.
G5: State that urea is a waste product removed in the urine.

7. FILTRATION
As blood flows through the kidneys, a lot of water and most of the substances dissolved in the plasma are filtered out. This includes urea, glucose, amino acids and salt.

8. RE-ABSORPTION
Many of these substances are needed by the body, so are RE-ABSORBED back into the blood.
Urea and just the right amount of water that the body needs to lose are NOT re-absorbed. They pass out of the kidneys, down to the bladder and are excreted in the urine

9. C1: Explain the process of urine production using a simple diagram of the nephron.

10. Kidney
tubule
Bowman’s capsule
Capillaries
Glomerulus
Collecting Tube

11. Part of Nephron Function Glomerulus Kidney Tubule Collecting Duct
Blood is filtered and collects in the Bowman’s Capsule
Kidney Tubule
Useful substances are re-absorbed (eg, glucose, amino acids) and pass back into the capillaries.
Collecting Duct
Final re-absorption of water occurs here. The amount re-absorbed is controlled by ADH (anti-diuretic hormone).

12. Amino Acids  Glycogen + Urea
C2: State the source of urea in the body and describe how urea is transported to the kidneys.
Urea is a poisonous nitrogenous (contains nitrogen) waste. It is made in the liver when surplus amino acids are broken down.
Amino Acids  Glycogen + Urea
Useful carbohydrate stored in the liver
Urea passes into the bloodstream and is transported to the kidneys where it is removed from the blood.

13. New term …… diuretic Opposite terms
Don’t copy this!!!!!!!
New term …… diuretic
A diuretic is a substance which causes an increase in the production of urine.
Opposite terms
eg, clockwise/anti-clockwise
social/anti-social
anti-viral

14. Diuretic Anti-diuretic
A diuretic is a substance which causes an increase in the production of urine.
Anti-diuretic
An anti-diuretic will reduce the production of urine.

15. C3: Explain the role of ADH (anti-diuretic hormone) in the regulation of water balance
= decrease production of urine
Anti-diuretic hormone is released by the pituitary gland (part of the brain).
Body can either produce lots of ADH or a little ADH
Lots of ADH
= less urine

16. Scenario 1: Drank too much water
Drink
too much
Blood too dilute
Releases
little ADH
Water conc. in blood normal
Water conc. in blood normal
Low volume of water reabsorbed by kidney
Large volume dilute urine to bladder

17. Scenario 2: Body has lost too much water
sweating
Blood too concentrated
Releases
lots ADH
Water conc. in blood normal
Water conc. in blood normal
High volume of water reabsorbed by kidney
Small volume concentrated urine to bladder

18. G6: Explain the implications of damage to the kidneys by accidents or disease
People can live with only one kidney, but if both kidneys become damaged, urea will build up and will eventually cause death if not treated.
Treatment
Dialysis (kidney machine)
Kidney Transplant

19. C4: Describe the benefits and limitations of replacement and “artificial” kidneys.

20. C4: Describe the benefits and limitations of replacement and “artificial” kidneys.1.
Page 50 Biology Booklet 2.
Complete pages 43-51 3.
Textbook Read/Revise/Take Notes/Answer Questions 4.
Last page of booklet – past paper questions/book