Lecture 25 Flashcards
What is osmoregulation?
A: The process of balancing water and solute concentrations to maintain internal homeostasis.
What do desert and marine animals have in common regarding water balance?
A: They both face desiccating environments and risk water loss.
How do freshwater animals maintain water and solute balance?
A: By conserving solutes, absorbing salts, and producing dilute urine.
What is excretion?
A: The removal of nitrogenous waste and other metabolic byproducts from the body.
How do albatrosses maintain osmolarity while drinking seawater?
A: Using specialized salt glands near the eyes to excrete excess salt.
Difference between osmolarity and tonicity?
A: Osmolarity is total solute concentration; tonicity refers to the effect on cell volume.
What are osmoconformers?
A: Animals (mostly marine invertebrates) that are isoosmotic with their environment.
What are osmoregulators?
A: Animals that expend energy to maintain osmotic balance, regardless of environment.
Stenohaline vs. Euryhaline animals?
A: Stenohaline tolerate only narrow osmolarity ranges; euryhaline tolerate wide fluctuations.
How do freshwater fish osmoregulate?
A: Avoid drinking, excrete lots of dilute urine, and actively absorb salts through gills.
What is anhydrobiosis? Give an example.
A: Survival strategy in dry environments where organisms lose body water.
E.g.: Water bears (tardigrades).
Energetic cost of osmoregulation depends on…?
A: The osmotic difference with the environment, membrane permeability, and solute transport energy.
What are the 4 key steps in excretory systems?
A: Filtration, Reabsorption, Secretion, Excretion
What is collected in the nephron’s Bowman’s capsule?
A: Filtrate containing salts, glucose, amino acids, vitamins, and nitrogenous wastes.
Some aquatic
invertebrates in
temporary ponds lose
most of their body water
and survive in a dormant
state. What kind of adaptation is this?
Anhydrobiosis
