Osmoregulation and Waste Disposal Flashcards
Osmoregulation
Management of the bodies water content and solute composition
How do animals regulate chemical composition of their body fluids
Balancing the uptake and loss of water and fluids (but must also manage metabolic waste products)
Osmoregulators
Expend energy to control their internal osmolarity
Osmoconformers
Isosmotic with their surroundings
What kind of osmoregulation are most marine invertebrates
Osmoconformers
What is osmolarity
The concentration of all the particles dissolved in body fluid
What kind of osmoregulation are most marine vertebrates
Osmoregulators
Marine fish osmoregulation
FIsh constantly loose water through their skin and gills
To balance this, these fish obtain water and food by drinking large amounts of seawater and they excrete. ions by active transport out of the gills.
Freshwater animal issue with osmoregulation
Constantly gain water by osmosis and lose salts by diffusion
How do freshwater protists balance excess water
Have contractile vacuoles that pump out excess water
How do freshwater fish maintain balance
- Excreting large amounts of very dilute urine
- Regaining lost salts in food
- Active uptake of salts from their surroundings
What does the amount/kind of nitrogenous waste depend on
- Energy budget
- How much and what kind of food animal eats
- Evolutionary history and habitat (especially water availability)
Animals that excrete nitrogenous waste as ammonia
- Need access to lots of water as ammonia is very soluble but can only be tolerated at very low concentrations
Aquatic species nitrogenous waste form
Often ammonia. Most of ammonia is lost as ammonium ions (NH4+) at the gill epithelium
What can freshwater fish do with ammonia ions
Exchange NH4+ for Na+ from the environment
Issues with excreting ammonia
Because ammonia is so toxic, it can only be transported and excreted in large volumes of very dilute solutions - A big issue for organisms that are water limited
How do water limited organisms dispose of nitrogenous waste without ammonia
Urea is synthesised in the liver by combining ammonia with carbon dioxide and excreted by the kidneys
Issues with urea as disposal
Energetically expensive
What animals use uric acid
Insects, birds, and reptiles
How is Uric acid different from ammonia and urea
Largely insoluble in water can can be excreted as a semisolid paste with small water loss
Pro and con of uric acid
Saves even more water than urea, however is even more energetically expensive to produce
How do shelled eggs of birds deal with nitrogenous wastes
Shelled eggs are impermeable, therefore soluble nitrogenous wastes trapped within could accumulate to dangerous levels. Therefore in these animals, Uric acid precipitatess out of solution and is stored within the egg as a harmless solid
What does osmotic regulation and metabolic waste disposal depend on in most animals
Ability of a layer, or layers, of transport epithelium to move specific solutes in controlled amounts in particular directions
Countercurrent exchange in fish
As blood moves anteriorly in gill capillary, it becomes more and more oxygen saturated. But, simultaneously encounters water with even higher oxygen concentrations because it is just beginning its passge over the gills.
anhydrobiosis in aquatic vertebrates
Dehydrate, losing almost all their body water, and survive in a dormant state
Trimethylamine oxide
A salt that sharks store making the sharks more salty than their environment
Purpose of Trimethylamine oxide
Salt ions dont constantly diffuse from the ocean into the shark
Why shouldn’t you shave a camel
Results in greater daily water loss
Beetle in desert adaptation to water conservation
Stand on a hillside and and water that collects on a beetle overnight will roll down into the beetles mouth so it can drink
How do we gain water and salts
Food, liquid, metabolism
How do we lose water and salt
Urine, Feces, Evaporation
Chemical reason as to why we produce nitrogenous waste
Proteins –> Amino acids
Nucleic acids –> Nitrogenous bases
Amino acid + Nitrogenous base = Amino group
Hyperosmotic
The amount of solutes in the fish is greater than that of the water
Hyposmotic
amount of solutes in fish is less than that of surroundings
