1. Chapter 44 Osmoregulation and Excretion

2. Fig. 44-2 Selectively permeable membrane Net water flow Hyperosmotic side Hypoosmotic side Water Solutes

3. Osmoregulation- the control of the concentration of body fluids. Diffusion- movement of substance from an area of greater concentration to an area of lower concentration Osmosis- diffusion of water through a semipermeable membrane

4. Adaptation to Marine Environment Reducing salt Seabird and marine iguana- nasal salt secreting gland Sea snake- sublingual gland Crocodile- lacrimal gland Fish gills- chloride cells Shark- rectal gland

5. Salt Excretion in Birds

6. Nitrogenous Waste Excretion Ammonia- toxic -Excrete directly into water- jellies -Detoxify  urea Urea- need lots of water to get rid of Uric Acid- birds & reptiles -more costly to produce than urea, but needs less water to be removed

7. Strategies to remove Nitrogenous Waste

8. Osmoconformer: isoosmotic Osmoregulator: hyper-, hypo-, ureoosmotic Euryhaline: wide tolerance range Stenohaline: narrow tolerance range Balancing NaCl in Blood Osmols- total solute concentration in moles of solute/liter of solution

9. Marine Fish: hypoosmotic H 2 O continually leaves body continually drinks seawater excretes salt through gills produces small amts of dilute urine Less salt than external environment

10. Freshwater Fish: hyperosmotic H 2 O continually enters body does not drinks water produces large amts of dilute urine More salt than external environment

11. Shark and Coelacanth: ureoosmotic Maintains high levels of urea and TMAO in blood excretes salt through rectal gland coelacanthRana cancrivora

12. Hagfish: ionosmotic nonregulator Seawater concentration = internal concentration

13. Osmolarity- measure of total solutes(dissolved particles) IonsFW m osmol/l SW m osmol/l Na+1470 Cl-1550 Ca++ variable10 Total101000 Osmolarity in Freshwater and Saltwater

14. HabitatNa + Cl - Urea seawatersw478558 hagfish (Myxine)sw537542 lampreyfw12096 Goldfish (Carassius)fw115107 Toadfish (Opsanus)sw160 Crab-eating frog (Rana)sw252227350 Dogfishsw287240354 freshwater rayfw150149<1 coelacanthsw197199350

15. Adaptations to Dry Environment Many desert animals don’t drink water Kangaroo rats lose so little water that they can recover 90% of the loss from metabolic water and gain the remaining 10% in their diet of seeds. Also have long loop of Henle

17. Most excretory systems produce a filtrate by pressure-filtering body fluids into tubules.

18. Flatworms have an excretory system called protonephridia, consisting of a branching network of dead-end tubules. –The flame bulb draws water and solutes from the interstitial fluid, through the flame bulb, and into the tubule system. Diverse excretory systems are variations on a tubular theme

19. Metanephridia consist of internal openings that collect body fluids from the coelom through a ciliated funnel, the nephrostome, and release the fluid through the nephridiopore. –Found in most annelids, each segment of a worm has a pair of metanephridia.

20. Insects and other terrestrial arthropods have organs called Malpighian tubules that remove nitrogenous wastes and also function in osmoregulation. –These open into the digestive system and dead-end at tips that are immersed in the hemolymph.

22. Nephron

24. Hormonal Control via Negative Feedback

25. Fig. 18.16 Regulation of Aldosterone secretion by renin-angiotensin- aldosterone (RAA) pathway

26. Moment of Zen