1. Practice Quiz #2
Multiple Choice Questions
D (Should say B&C) D B A C

3. S S R R
Filtrate F
Blood Plasma S E R R
Urine

4. The Role of ADH & Aldosterone
Biology 30S
The Excretory System

5. Antidiuretic Hormone: ADH
ADH is a hormone made by a part of the brain called the hypothalamus & stored in & released by the pituitary gland.
ADH is a special protein that affects the permeability of the nephron.
Targets mostly the collecting Tubules, but also the PCT & DCT.

6. ADH
Is responsible for “osmoregulation” or maintain a balance in the water and salt content of the blood (homeostasis)
It is because of ADH that the kidneys are able to either conserve water or eliminate excess water depending on the circumstances.
We can remember it as the anti-water loss or as the “anti-pee” hormone.

7. ADH
Method:
Special chemoreceptors in the hypothalamus monitor the salt levels of blood and affect the amount of ADH that is release by the pituitary.
Two different possible scenarios can occur

8. ADH: SCENARIO 1
When salt levels in the blood are too high, the chemoreceptors tell the pituitary to release and increased amount of ADH into the blood.
The ADH flows through the blood to the nephrons.
ADH attaches to target sites and cause the pores of the nephrons to open wider
Increases the nephrons permeability to water.

9. ADH: SCENARIO 1
This increase permeability will allow more water to be reabsorbed back into the blood.
As the water content of the blood increases, the salt [ ] that was once too high, will now decrease.
As a result there will be less water is available to make urine.

10. ADH: SCENARIO 1 Urine Characteristics: ?
Dark yellow in color
High concentration of wastes/salts
Stronger Smell
Less urine produced
In Summary: [ ] of salt =  ADH released by pituitary
More ADH = more H2O reabsorbed = less H2O in pee = less pee

11. ADH: SCENARIO 2
When the salt level in the blood is too low, the opposite of scenario 1 will occur.
The chemoreceptors in the hypothalamus will tell the pituitary to release less ADH.
Less ADH will attach to the walls of the nephron, allowing more of the pores of the nephron to remain closed.
This will result in less water being reabsorbed by the blood, the blood’s salt [ ] will eventually increase.

12. ADH: SCENARIO 2 Urine Characteristics: ?
Lighter in color
Less concentration of wastes/salts
Less smelly
More urine produced
In Summary: [ ] of salt =  ADH released by pituitary
Less ADH = LEss H2O reabsorbed = More H2O in pee = more pee

13. NEGATIVE FEEDBACK LOOPS
ADH
These two scenarios are examples of what?
HOMEOSTASIS & OUR
NEGATIVE FEEDBACK LOOPS
Use your notes to fill in the Negative Feedback diagram for ADH

14. Control Center Pituitary Gland Receptor Effector Release of ADH Change
Osmoreceptors
In the hypothal.
Send a msg to
the pituitary
Gland
Effector
Release of ADH
Change
Water[ ] in the blood is lowered
Change
Water is reabsorbed
in the blood.
Feeling thirst/
drinking fluids
Normal Conditions
Water [ ] in the blood-
Stream
Causes
Intense physical activity without fluid intake

15. Aldosterone A hormone made, stored and secreted by the adrenal glands.
Cap like organs that sit on top of each kidney
Is a special protein that helps to control blood pressure.
controls the amount of water that is in the blood like ADH but does so in different ways

16. Aldosterone
Aldosterone regulates the amount of water in the blood by regulating the amount of salt that gets reabsorbed from the nephron back into the blood.
When more water is reabsorbed back into the blood, so is more water.

17. Aldosterone
Method:
a special receptor in the kidney measures BP and sends messages to blood vessels to cause either vasodilation or vasoconstriction

18. Aldosterone: SCENERIO 1
If BP is low, this will cause the adrenal glands to release more aldosterone into the blood stream.
“tells” the kidneys to send more salt back into the blood.
Increased reabsorption of salt into the blood causes more water to be reabsorbed back into the blood.
Volume of blood will increase due to the increase in the amount of water that is added to the blood.

19. Aldosterone: SCENERIO 1
In Summary: Reabsorption of salt   water reabsorption to blood Volume of blood  due to  in H2O reabsorption =  in BP

20. Aldosterone: SCENERIO 2
If BP is high, the opposite happens.
In Summary
Reabsorption of salt   water reabsorption to blood
Volume of blood  due to  in H2O reabsorption =  in BP

21. Control Center Adrenal Glands Receptor Effector Release of Aldosterone
Special receptors
In the kidney
Effector
Release of
Aldosterone
Change
Vasodilation: Water & salt [ ] in the blood is low
Change
Vasoconstriction:
Less water/salts will be reabsorbed
into the blood.
[ ] in blood increases
Normal Conditions
Normal Water & salt [ ] in the blood-stream
Causes
Stressful situation cause heart to beat faster & increases Blood pressure

22. Diuretics
Alcohol and caffeine are diuretic substance that function to increase urine production.
They block the receptors in the nephron walls and don’t allow ADH to bind there.
Less ADH causes the same events as Scenario #2 of ADH to occur
Increased loss of dilute urine.

23. Diuretics Consumption of diuretics can lead to dehydration
One of the causes of a “hangover” after consuming too much alcohol.
Can be used to treat disorders such as Edema or hypertension

24. Fun Quiz!
Refer to your notes on:
ADH
Aldosterone
Diuretics

25. ADH - True or False? ADH is made in the pituitary gland False
made in the hypothalamus
The pituitary gland is part of the brain
True
More ADH sent to the nephron in a person who is dehydrated
true

26. ADH - True or False? Less ADH causes less pee False
more ADH = less pee
Dehydration is determine by the salt concentration of the blood
True
More ADH causes the urine to lighten in color
more ADH = darker urine

27. Aldosterone - True or False?
Aldosterone is made in the hypothalamus
false,
made in adrenal glands
Aldosterone controls blood pressure
True
Aldosterone also controls the amount of water in the urine
true

28. Aldosterone – True or False?
When salt moves, water also moves
True
When blood pressure is high, more aldosterone is released
False
high BP = less aldosterone
Less aldosterone results in more urine
true

29. Diuretics - True or False?
Diuretics are chemicals that make more water go to the urine
True
Diuretics prevent the action of ADH
Pepsi and beer are good to drink when you are really thirsty
false
they dehydrate you more
Diuretics can be used to treat hypotension

30. Today’s Assignment
Complete the Compare & Contrast of ADH & Aldosterone on the back of the booklet.
Due before the end of class
Work on your Excretion Disorders Questions
Due Tomorrow!
Study for Quiz #2 Tomorrow!