1. chpt. 44
Osmoregulation
& Excretion

2. Osmoregulation
- Regulating solute concentrations (ions & poisonous N-compounds) in the blood
- Balancing the gain and loss of water from the blood

3. Excretion
Getting rid of N-containing waste products (produced via. metabolism)

4. Metabolic waste… if they accumulated, they would reach toxic concentrations!!!
must be dissolved in water when removed from a body.

5. Types of metabolic waste…

6. NH3 = high toxicity!
NH3 = can only be tolerated at low concentrations
Most aquatic animals secrete ammonia immediately in the water where it washes away!

7. NH2 = lower toxicity compared to ammonia NH3
NH2 = can be stored in the body, therefore, no need to be surrounded by water for instant elimination
A disadvantage is that these animals must use ATP to produce Urea from Ammonia

8. GREAT for animals with little access to water
Uric acid = lowest toxicity compared to NH3
Uric acid = insoluble in water, and can be stored in an egg/ excreted as a paste / LESS H2O LOSS!
GREAT for animals with little access to water

9. COST: takes even more ATP to produce than Urea (NH2)

10. Increasing amount of ATP to produce end product
decreasing toxicity & less water needed to excrete

11. you require 2L of
water per day

12. The excretory system is a system of simple organs, tubes, muscles, and nerves -they work together to create, store, and carry urine

13. Excretory System
excretes waste products
regulates water & salt

14. Excretory System
filters blood / produces URINE

15. Excretory System
carries urine to the bladder

16. Excretory System
temporarily stores urine

17. Excretory System
urine exits body via. this tube

18. Water level in blood, must remain within a certain range of osmolarity, the hypothalmus monitors this

19. The Excretory System focuses on the KIDNEY
Capsule
A. Renal Vein
B. Renal Artery
Renal Medulla
Ureter
Renal Cortex

20. The Excretory System focuses on the KIDNEY
Blood pressure is higher in the vessels that lead to the kidney… WHY?

22. Water level in blood, must remain within a certain range… the kidney assists in this

23. Lets look inside the KIDNEY

24. NEPHRON- filter element  
Proximal Tubule  
NEPHRON- filter element

25.  Fluid forced through the capillaries forming FILTRATE
NaCl
H2O 
Proximal Tubule
NH3 H+
Fluid forced through the capillaries forming FILTRATE

26. NaCl
H2O 
Proximal Tubule
NH3 H+
Secretion to maintain a constant pH & reabsorption of H2O & NaCl into epithelium

27. NEPHRON- filter element  
Proximal Tubule  
Descending limb of the Loop of Henle 
NEPHRON- filter element

28.  Reabsorption of water into the interstitial fluid
NaCl
H2O
NH3 H+ 
Descending limb of the Loop of Henle
Reabsorption of water into the interstitial fluid

29.  Filtrate becomes more concentrated
NaCl
H2O
NH3 H+ 
Descending limb of the Loop of Henle
Filtrate becomes more concentrated

30. NEPHRON- filter element  
Proximal Tubule 
Descending limb of the Loop of Henle   
Ascending limb of the Loop of Henle
NEPHRON- filter element

31.  Reabsorption of NaCl into interstitial fluid
H2O
NH3 H+
Ascending limb of the Loop of Henle 
Reabsorption of NaCl into interstitial fluid

32.  Filtrate becomes more dilute! Ascending limb of the Loop of Henle
NaCl
H2O
NH3 H+
Ascending limb of the Loop of Henle 
Filtrate becomes more dilute!

33. NEPHRON- filter element  
Proximal Tubule 
Descending limb of the Loop of Henle   
Ascending limb of the Loop of Henle 
Distal Tubule
NEPHRON- filter element

34.  pH regulation secretion of water & salt Distal Tubule H2O NaCl H2O
NH3 K+ H+ H+
pH regulation secretion of water & salt

35. Carries filtrate secretes water & urea
NaCl
H2O
NH3 H+
Carries filtrate secretes water & urea 
Collecting Duct

36. Filtrate becomes more concentrated
NaCl
H2O
NH3 H+
Filtrate becomes more concentrated 
Collecting Duct

37. URINE CONCENTRATION changes throughout the journey!!

38. hypothalamus detect an increase in the osmolarity
Osmoreceptors
in hypothalamus
Thirst
Hypothalamus
Drinking reduces
blood osmolarity
to set point
ADH
THE NERVOUS SYSTEM AND HORMONES monitor this, and can REGULATE KIDNEY FUMCTIONS
Increased
permeability
Pituitary
gland
Distal
tubule
H2O reab-
sorption helps
prevent further
osmolarity
increase
STIMULUS
The release of ADH is
triggered when osmo-
receptor cells in the
hypothalamus detect an
increase in the osmolarity
of the blood
Collecting duct
Homeostasis:
Blood osmolarity

39. hypothalamus detect an increase in the osmolarity
Osmoreceptors
in hypothalamus
Hypothalamus
ADH
Pituitary
gland
ADH produced in the hypothalmus -> stored in pituitary gland (promotes reabsorption of water into blood)
STIMULUS
The release of ADH is
triggered when osmo-
receptor cells in the
hypothalamus detect an
increase in the osmolarity
of the blood

40. hypothalamus detect an increase in the osmolarity
Osmoreceptors
in hypothalamus
Hypothalamus
ADH
Increased
permeability
Pituitary
gland
Osmoreceptor cells in hypothalmus monitor the osmolarity of blood
above 300 =>ADH released
Distal
tubule
STIMULUS
The release of ADH is
triggered when osmo-
receptor cells in the
hypothalamus detect an
increase in the osmolarity
of the blood
Collecting duct

41. hypothalamus detect an increase in the osmolarity
Osmoreceptors
in hypothalamus
Hypothalamus
ADH
Increased
permeability
Pituitary
gland
ADH increases the permeability of interstitial tissue (in the kidney) to water.
Increases water reabsorption out of nephron
Distal
tubule
H2O reab-
sorption helps
prevent further
osmolarity
increase
STIMULUS
The release of ADH is
triggered when osmo-
receptor cells in the
hypothalamus detect an
increase in the osmolarity
of the blood
Collecting duct
Homeostasis:
Blood osmolarity

42. hypothalamus detect an increase in the osmolarity
Osmoreceptors
in hypothalamus
Hypothalamus
ADH
Increased
permeability
Pituitary
gland
Activity of receptor cells in hypoth. reduced-> NEGATIVE FEEDBACK
Distal
tubule
H2O reab-
sorption helps
prevent further
osmolarity
increase
STIMULUS
The release of ADH is
triggered when osmo-
receptor cells in the
hypothalamus detect an
increase in the osmolarity
of the blood
Collecting duct
Homeostasis:
Blood osmolarity

43. hypothalamus detect an increase in the osmolarity
Osmoreceptors
in hypothalamus
Hypothalamus
ADH
Increased
permeability
Pituitary
gland
Activity of receptor cells in hypoth. reduced-> NEGATIVE FEEDBACK
Less ADH released!
Distal
tubule
H2O reab-
sorption helps
prevent further
osmolarity
increase
STIMULUS
The release of ADH is
triggered when osmo-
receptor cells in the
hypothalamus detect an
increase in the osmolarity
of the blood
Collecting duct
Homeostasis:
Blood osmolarity

44. hypothalamus detect an increase in the osmolarity
Osmoreceptors
in hypothalamus
Thirst
Hypothalamus
Drinking reduces
blood osmolarity
to set point
ADH
Increased
permeability
Pituitary
gland
ADH stored in pituitary gland
Distal
tubule
H2O reab-
sorption helps
prevent further
osmolarity
increase
STIMULUS
The release of ADH is
triggered when osmo-
receptor cells in the
hypothalamus detect an
increase in the osmolarity
of the blood
Collecting duct
Homeostasis:
Blood osmolarity

45. Osmoreceptor cells in hypothalmus monitor the osmolarity of blood
Osmoreceptors
in hypothalamus
Hypothalamus
ADH
Increased
permeability
Pituitary
gland
Osmoreceptor cells in hypothalmus monitor the osmolarity of blood
below 300 => very little ADH released
Distal
tubule
Collecting duct

46. Decreases permeability of distal tube and collecting duct
Osmoreceptors
in hypothalamus
Thirst
Hypothalamus
Drinking reduces
blood osmolarity
to set point
ADH
Pituitary
gland
Decreases permeability of distal tube and collecting duct
Distal
tubule
Collecting duct
Homeostasis:
Blood osmolarity

47. Vampire bats are unique, they feed on blood…

48. South American Vampire bats are unique, they feed on blood…

49. They use their teeth, & make an incision in their prey

50. They have anticoagulents so the blood does not clot, prey not harmed

51. They fly for HOURS to search for suitable victims, they need MUCH blood for energy

52. Problem: they would be too heavy to fly!!!

53. Their kidneys are specialized to offload MUCH water from the blood - VERY DILUTE URINE, now they can fly back home.

54. Next Problem: blood has much protein… lots of UREA, little access to drinking water while roosting!!!

55. Kidneys produce small quantities of highly concentrated urine.

56. WHAT AN EVOLUTIONARY ADAPTATION!!! GO DARWIN!

57. Structure and function are related in the various organ systems of animals. Select two of the following four organ systems in vertebrates: * respiratory * digestive * excretory * nervous For each of the two systems you choose, discuss the structure and function of two adaptations that aid in the transport or exchange of molecules (or ions). Be sure to related structure to function in each example.