Flashcards in Homeostasis - part 1 Deck (23)
What are the 5 basic groups of fish that display the different types of ionic regulation?
Hagfish - osmoconformer
What is an osmoconformer?
Blood chemistry matches that of its environment. Narrow range in which it can live.
What is an osmoregulator?
Fish that will change blood osmolality/osmolarity to be different from its environment.
What is hyperosmoregulation?
Blood osmolarity above environment. (Freshwater)
What is hypoosmoregulation?
Blood osmolarity below environment, (Marine)
Describe a stenohaline fish.
Narrow range of environmental osmolarity that the fish can withstand.
Describe a euryhaline fish?
Can withstand a broad salinity range.
What is osmosis?
Passive movement of water along its concentration gradient.
For salwater fish, what is the direction of water flow?
- more salt in environment so water flows out of fish
- more particles in fish so water flows into the fish
What are the different ion exchange surfaces in fish?
What are the most important ones?
Rectal gland (elasmobranchs)
What are the two parts of gills important for ion exchange?
Filaments and lamellae
What are lamellae for?
What are filaments for?
Support lamellae and are the site of osmoregulation, especially in teleosts.
How are kidneys involved in osmoregulation?
absorb or secrete ions
get rid of wastes
How is the GI tract involved in osmoregulation?
Mostly in water exchange and uptake.
How is the Rectal gland involved in osmoregulation?
Location of ion exchange in sharks and rays (only in them).
Site of active excretion of ions (take from blood and excrete them)
Active transport of ions into rectal gland
What is the osmolarity of freshwater?
How does a hagfish compare to osmolarity of a marine environment?
Largely the same for: Na, Cl, Ca, Urea and total.
How does the marine shark compare with the marine environment?
Total similar but higher
Urea way higher
How does a marine teleost compare to a marine environment?
Ca close but lower
Total much lower
How does a freshwater shark compare to a freshwater environment?
How does a freshwater teleost compare to its environment?
Ca same but higher