1. Osmoregulation in Animals
Chapter 44

2. Osmoconformers vs. Osmoregulators

3. How does a salmon survive?
Usually osmoregulation uses about 5% of metabolism.
Osmoregulation in extreme saline conditions: up to 30%

4. Compare and Contrast
Osmoregulation in saltwater vs. freshwater fish!

5. Compare and Contrast the Following Excretory Organs
Name of Structure
Organisms
How structure works
Protonephrida
Metanephridia
Malphigian Tubules

6. The Pee Problem What happens to nutrients after they enter the body?
What gets used? What gets stored? How is waste removed?
Compare the elements contained in proteins to the elements in the storage molecules. What is it that doesn’t get stored?

7. Waste products affect water balance
Habitat dictates the toxicity of waste that an animal can tolerate
Energy cost to producing less toxic urea and insoluble uric acid

8. Diffusion, osmosis, & active transport in the body
The Kidney & Dialysis
Diffusion, osmosis, & active transport in the body

9. Gross Anatomy Posterior in the abdominal cavity Bean shaped
Just below the rib cage
Size of a fist

10. What do they do? Kidneys filter waste products and make urine
Waste products from cells end up in the blood
Blood circulates around the body including the kidneys
Artery = away from the heart, into the kidney
Capillaries = thin walls allow waste to leave
Vein = leaves the kidney, back to the heart

12. Kidney Facts
The rate of filtration is approximately 125 ml/min or 45 gallons (180 liters) each day. Considering that you have 7 to 8 liters of blood in your body, this means that your entire blood volume gets filtered approximately 20 to 25 times each day!

13. A closer look

14. Nephron The repeating functional unit of the kidney
A semi-permeable tube whose job is:
Filtration
Reabsorption
Secretion

15. How is the nephron organized?
Areas of the nephron:
Glomerulus
Bowman’s capsule
Proximal Tubule
Loop of Henle -
ascending
Descending
Distal Tubule
Collecting duct

16. Components of Blood

17. Filtration Plasma is the liquid portion of the blood
Plasma contains water, ions, glucose, amino acids, and waste
Blood pressure pushes plamsa out capillaries and into the nephron tube

18. Reabsorption
Both active and passive transport move good molecules from the nephron tube back into the blood stream
Sodium is pumped (actively transported) back into the capillaries
Water follows  osmosis
Bad stuff like waste is left in the tube headed to the bladder
Anything that doesn’t get reabsorbed into the blood gets “peed” out (becomes urine)

19. Secretion Opposite of reabsorption
Waste (H+ ions, drugs) are pumped from capillaries directly into the tube

20. Review of major processes

21. Recipe for urine?

22. Key Concept: Active transport drives the passive transport of water
Counter-current multiplier system

23. How does structure meet function?
Cells that make up the tube are different depending on their jobs!

24. Structure Meets Function
Fluids must pass through transport epithelial cells for regulation
Tight junctions force fluids to enter cells
Semipermeable cell membranes (of transport epithelial) control the movement of solutes between internal fluids and the external environment by sorting, pumping, and secreting solutes

25. Hormonal Balance Two systems: What is the stimulus for each system?
What hormones are involved?
How do hormones cause a response?

26. ADH

27. RAAS

28. Reviewing Hormones
Mini Case Study: Alcohol inhibits ADH. A college student was binge drinking. The student passed out and friends just figured they’d let him “sleep it off.” Knowing what you know about the feedback and osmoregulation, why is this a bad choice?

29. What if it doesn’t work? Kidney usage is usually measured in percent
If you lose a kidney you can still filter 100% (you really only need one)
When total kidney function drops below 20% it can be lethal
Treatment- dialysis

30. Hemodialysis hemo = blood
Internal filters don’t work, use an external filter
Blood is filtered through an external machine

31. The dialyzer Nephron is to kidney as dialyzer is to hemodialysis
Much simpler than the nephron
Blood on one side, liquid on the other
Semi-permeable membrane between

32. Why does it work?
A waste product like urea is more concentrated in the blood than in the fluid (dialysate) so the urea passes through and is washed away

33. Life on dialysis Kidneys work 24/7 to get the job done
Dialysis is periodic, not continuous
Dialysis takes 4-5 hours
Why can’t all the blood be filtered at once?
Patients go to a clinic 3 times a week (MWF or THS)

34. Is hemodialysis just as good as a kidney?
What do you think?

35. Hemodialysis Effectiveness
About 10% as effective as normal kidneys
Became available in the early 60s
Some of the first patients are still alive
Not a full life expectancy
Without dialysis- certain death
20 million Americans

36. Be the doctor! Manipulating the dialysate
In end-stage renal (kidney) failure potassium concentrations get really high
This can cause big problems (Na+/K+ pump)
What should you do to the concentration of potassium ions in the dialysate to fix this problem?