Download Keeping Healthy (B2)

Homeostasis
• 5 minute poster
• Work as a team to
produce a poster of
everything you can
remember about
homeostasis WITHOUT
looking at your books
End
Water Balance
• Lesson Learning Outcomes:
Describe the
role of the
kidneys in
water
homeostasis
Explain the role
of ADH in
water balance
Increasing Difficulty
Predict the
effects of
different drugs
on the amount
of urine
produced
Water gains and
losses
How is water
gained?
How is water
lost?
The Kidney
• The kidneys have
two jobs:
– Water balance
– Excretion
• They can change
the amount of
urine you make
Urine
concentration
• What do you think your urine would be
like if you….
GO FOR A TEN MILE RUN ON A
HOT SUNNY DAY?
Urine
concentration
• What do you think your urine would be
like if you….
DRINK A BOTTLE OF WATER IN
30 MINUTES?
Urine
concentration
• What do you think your urine would be
like if you….
EAT A REALLY SALTY MEAL?
Urine
concentration
• What do you think your urine would be
like if you….
WAIT FOR THE METRO FOR AN
HOUR IN THE SNOW WITHOUT
A COAT?
Left hand page
Right hand page
Summarise the role of the
kidneys in water balance
Summary
Water Balance
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Drugs
• Some drugs affect the way the body produces
urine
• This happened in the 90s (when I was in
middle school)
• WHY DID LEAH BETTS DIE?
Left hand page
Explain why Leah Betts died
Summary
Right hand page
Water Balance
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Ecstasy
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Why did Leah Betts
die?
• It was the first time she took ecstasy and it wasn’t
contaminated
• She wasn’t dancing so she didn’t dehydrate
• She drank about 7 litres of water in a few hours
• Water balance is controlled by a hormone call Antidiuretic hormone (ADH)
• ADH makes the kidney tubules more permeable to
water so more water can be reabsorbed into the blood
and less urine is produced
• Ecstasy makes ADH production occur even when it is not
needed
Drugs
Name of
Drug
Caffeine
Alcohol
Ecstasy
Affect on release of
ADH
Affect on the
volume of urine
produced
Drugs!
Name of
Drug
Affect on release of
ADH
Affect on the
volume of urine
produced
Caffeine
Suppresses ADH
production
Suppresses ADH
production
Increases ADH
production
Increases the
amount of urine
Greatly increases
the amount of urine
Reduces the volume
of urine produced
Alcohol
Ecstasy
Negative feedback
Receptors in brain
Detects increase
Hypothalamus
(brain)
Sweat Gland
brings about change
(decrease)
37C
Receptor in brain
and skin
Detects decrease
Hypothalamus
(brain)
Muscle Shiver
brings about
change (increase)
Left hand page
Right hand page
Summary
Draw a negative feedback
loop for water balance.
Water Balance
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Ecstasy
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Negative feedback and ADH
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