PPT Slide
- Semi-aquatic and aquatic amphibians of freshwater environments face a different osmotic challenge than arid adapted species.
- Osmolality of body fluids greater than that of surrounding medium. Because of highly permeable skin:
- Influx of water _ large amount of dilute urine.
- Loss of ions outward _ active transport across skin to replenish ions.
- Salt water and amphibians. ~12 salamanders & ~60 anurans inhabit/tolerate brackish environments.
- Accumulate/retain organic and inorganic solutes _ raises internal osmolalities of body fluids (300-500 mmole/kg H20).
- Internal osmolality greater than surrounding environment.