1. The Excretory System
9.5
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2. Unicellular Organisms
water balance is often maintained by contractile vacuoles
video of Paramecium:

3. Excretion in Earthworms
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4. Excretion in Grasshoppers
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5. Human Excretory System
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6. Renal Blood Flow)
blood is brought to the kidneys by the renal arteries
filtered blood leaves the kidneys through the renal veins
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7. The Urinary System
kidneys can hold up to 25% of the body’s blood at a time
kidneys filter the blood
urine (with wastes and toxins) is conducted to the bladder through the ureters

8. Kidney Structure Basic structure: cortex medulla renal pelvis
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9. Kidney Kiwi
Found this website of a medical illustrator on December 6, 2011
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10. Kidney Kiwi Dissection

11. Nephron the functional unit of the kidney is the nephron
there are about 1 million nephrons in each kidney

13. Review Kidney Structure…

14. Image from: http://commons. wikimedia

16. Image from :http://kcfac. kilgore. cc. tx

17. (Image from: http://www. medical-illustrations
Afferent Arrives…Efferent Exits

18. How is urine formed?

19. Urine Formation filtration reabsorption secretion
(Image on previous slide from: ,-Sterile.html

20. Filtration higher blood pressure in glomerulus
water, ions, smaller dissolved molecules (glucose, amino acids, urea) can move through the walls of the glomerulus
your kidneys filter your entire blood plasma 65 times every day!
glucose, NaCl, H+ ions, amino acids,

21. Reabsorption ion pumps reabsorb Na+, K+, Cl- (active)
active transport proteins reabsorb pretty much all amino acids, glucose & other nutrients
filtrate becomes hypoosmotic to interstitial fluid, so water is reabsorbed by osmosis and through aquaporins
If you produced 120 mL of urine a minute…
(your bladder’s stretch receptors signal to your brain when there is 200mL of urine; can hold up to )
Osmotic gradient created by glucose, amino acids moves water back to blood.

22. Where? a lot of reabsorption occurs in the proximal convoluted tubule
filtrate with high concentration of urea and other wastes enters loop of Henle and then distal convoluted tubule:
more water and ions (Na+& Cl-)are reabsorbed

23. Where (cont’d)?
collecting ducts are permeable to water but not salt ions, so more water is reabsorbed
at bottom of medulla, urea is reabsorbed through passive urea transporters (increasing concentration gradient…more water reabsorbed)

24. Secretion
H+ ions (active) to adjust blood pH (HCO3- is also reabsorbed to balance)
products of detoxified poisons (passive)
water-soluble drugs (passive)
nitrogen-containing wastes (such as small amounts of NH3)
in the proximal and distal convoluted tubules

25. Animations I like this narrated animation; diagram is easy to follow:
Narrated animation on urine formation; good amount of detail:
Slideshow with animation; shows detail on what substances are reabsorbed, secreted & where:

26. Kidney Disorders

27. Urinalysis
can be used to detect many metabolic and kidney disorders as well as urinary tract infections
urine can be assessed using a dipstick or at a laboratory

28. Multiple Test Dipstick
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29. Diabetes Mellitus Type 1 - body cannot produce insulin
Type 2 - cells fail to use insulin properly
gestational - hormones of pregnancy interfere with action of insulin
urinalysis would show high levels of glucose (and greater volumes of urine)

30. Kidney Stones
caused by precipitation of minerals, can be alkaline or acidic
VERY painful
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31. Kidney Stones - Treatment
time…
lithotripsy (shock-wave therapy)
ureteroscopy (and placement of stent or surgical removal of stone)
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32. Dialysis
for low-functioning kidneys, dialysis machine can filter blood
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33. (Image from: http://www.metrohealth.org/body.cfm?id=1452)