Osmotic Regulation (Test Three) Flashcards
What is the chief reason for animals needing water?
Water is where life’s chemical reactions occur.
What are two reasons why animals need salt?
- To maintain blood pressure
- Essential for nerve and muscle function
What is the maintenance of homeostasis of water and salt content referred to as?
Osmoregulation
What does osmoregulation aim to accomplish?
To maintain internal solute concentration within a range that allows for cellular function.
What can osmoregulation have a negative effect on?
Cellular metabolism
What structure regulates the ion concentration?
Selectively permeable membrane
(can alter ion and water flow on each side)
Discuss the salt/water balance of marine invertebrates.
Since their body surfaces are permeable to water and salts, the concentration rises/falls with changes in sea water, which is relatively stable.
Where in the ocean would general concentration fluctuate much more?
Along coasts and estuaries (where salt water meets fresh water)
What is one example of an animal that has better osmoregulation because of their habitat?
The shore crab has better osmoregulation than the spider crabs.
What was the draw and one drawback to jawed fish entering freshwater rivers during the Silurian and Devonian periods?
Draw - abundant food unexplored habitat
Drawback - challenge of osmoregulation
How did the first freshwater fish deal with taking on excess water caused by the new environment?
By developing many adaptive mechanisms to unload excess water
What is the Glomeruli?
The Glomeruli is the tiny network of capillaries that compose the functional unit of the kidney (nephron) which filters waste products from the blood.
How do freshwater fish maintain an osmotic and ionic balance in their environment?
The fish actively absorbs sodium chloride across the gills, and some salt comes with food to balance themselves in their ultra hypotonic environment
How do freshwater fish get rid of excess water?
The glomerular kidney of the fish reabsorbs the sodium chloride and produces dilute urine which is then excreted.
Where do modern, oceanic, bony fishes descend from?
They are descend from freshwater fishes that returned to the sea.
How do Marine fish and freshwater fish differ in the challenges they face?
A freshwater fish, in a hypotonic environment, must deal with the problem of keeping the salt that comes in and removing excess water.
A marine fish must drink saltwater to replace the water that is lost since the environment is hypertonic. The gills actively secrete NaCl outward while water is lost osmotically. The kidneys also excrete MgSO4 and little water
Describe the movement of water and solutes across frog skin.
Water can freely enter the permeable skin and the skin actively transports ions from the environment.
Similar to freshwater fish, to eliminate excess water, the kidneys absorb NaCl and form dilute urine, but the urine is instead stored temporarily in the bladder, and remaining NaCl is removed and returned to the blood
Where do all metabolic activities, and Fertilization occur?
In water
Where is water produced in aerobic respiration?
At the end of the electron transport chain, because Oxygen is the final electron acceptor.
What are some ways that animals take on water?
- From stored fats while swimming
- Absorption from air
- Strictly aerobic respiration
- Drinking
Why did excretion of wastes become a special problem in water conservation?
Because the end product of protein breakdown (NH4) ammonia is highly toxic, and is water soluble.
How do fish deal with ammonia?
They excrete it across the gills and water washes it away
How do insects, reptiles, and birds deal with ammonia?
They convert it to uric acid which is insoluble.
How do mammals deal with ammonia?
They convert it to urea, which is less toxic
