Chapter 28: Water & Salt Environment
replacement of water
1. drink seawater (gains NaCl ions from ocean) 2. low excretion of urine (HYPERosmotic)
modes of water loss
1. integument 2. respiration 3. excretion (evaporative water loss is integument and respiration combined)
passive salt and water exchanged determined by:
1. magnitude of osmotic and ionic gradients 2. permeability of animal's outer body 3. surface area
marine elasmobranch fish (sharks, rays)
HYPERosmotic and hypoionic osmotic pressure is slightly higher than saltwater (less ions in body but maintain hyperosmotic pressure, through urea and rectal salt glands that excrete)
all freshwater fish are ________
HYPERosmotic regulators (higher ion concentration than freshwater environment)
marine teleost fish are _______ to seawater
HYPOosmotic (less ions inside body than inside) (think of ocean: a desiccating/dry environment)
reptiles and birds
HYPOosmotic regulators (water loss and salt loading through salt glands)
Do fish drink water?
No, water is already diffusing into fish
excretion of Cl is _____
active
Freshwater animals transport sodium into their body from the environment via
active transport
marine invertebrates
are isosmotic to seawater (octopi, sponges, annelid) ACTIVE uptake of ions from seawater
hyper-isosmotic regulators
blue crab, amphipod, carp (first HYPER because it is above the line, then isoosmotic)
If a freshwater fish takes in a quantity of water from its dilute environment by osmosis, the osmotic pressure in its plasma will tend to (Thought process: what would happen after a while?)
decrease (after awhile it will equalize)
more lipids in integumentary areas
equals LESS water loss
more SA
equals MORE evaporative water loss
freshwater crabs maintain higher osmotic pressure?
excrete isosmotic urine
(Freshwater fish) How do fish handle an influx of water?
excretion (hyperosmotic regulators) ACTIVE ion uptake (requires ATP)
Which of the following animals is NOT a hypoosmotic regulator?
freshwater fish (hyper)
compare and contrast marine and freshwater fish. What are their environments like? How do they osmoregulate? (short answer)
freshwater: hyperosmotic, water DIFFUSES into fish, gills: MRC (mitochondria rich cells =) active UPTAKE of Na and Cl low osmolarity in environment marine: water DIFFUSES OUT, Cl actively transported OUT high osmolarity in environment hypoosmotic regulators
water turn over is _______ in ______ than in ectotherms
higher, endotherms
low salinities (hyper-hypoosmotic)
hyperosmotic
low salinities (hyper-isosmotic)
hyperosmotic
high salinities (hyper-hypoosmotic)
hypoosmotic
arthropods are
isosmotic
high salinities (hyper-isosmotic)
isosmotic
higher temperatures
lose more water because lipids lose their form
trout living in very "soft" freshwater have what kind of cells in gills?
mitochondria rich cell
hard water contains _____ minerals.
more
excretion (dry environment)
more HYPERosmotic (greater concentration)
marine mammals
most concentrated urine of all species hypoosmotic pressure salt glands but answer is unclear
hagfish
only vertebrate that is isosmotic to seawater
Gaining water (largely through diffusion) determined by
passive transport
respiratory water loss
perspiration (dogs and noses)
exhaling cooler air
reduces body temperature, lose LESS water vapor (think back to hot environments=more water vapor loss and vice versa) **MINIMIZE WATER LOSS
weight specific water loss is _______ between large and small animals
the SAME
freshwater fish (where do water and ions flow?)
water diffuses INTO fish active UPTAKE of Na and Cl
marine fish (where do water and ions flow?)
water diffuses OUT of fish ACTIVE EXCRETION of CL