fchghgfc Flashcards
What is osmoregulation?
Osmoregulation is largely based on balancing the uptake and loss of water and solutes.
What drives the movement of solutes and water in osmoregulation?
The driving force is a concentration gradient of one or more solutes across the plasma membrane.
What is osmosis?
Osmosis is the process by which water enters and leaves cells.
What is osmolarity?
Osmolarity is the solute concentration of a solution, determining the movement of water across a selectively permeable membrane.
What happens when two solutions are isoosmotic?
Water molecules will cross the membrane at equal rates in both directions.
What is the net flow of water between solutions of different osmolarity?
The net flow of water is from the hypoosmotic to the hyperosmotic solution.
What are osmoregulators?
Osmoregulators expend energy to control water uptake and loss in a hyperosmotic or hypoosmotic environment.
How do marine bony fishes manage water loss?
They balance water loss by drinking large amounts of seawater and eliminating the ingested salts through their gills and kidneys.
How do freshwater animals maintain water balance?
They constantly take in water by osmosis and maintain water balance by drinking almost no water and excreting large amounts of dilute urine.
What is anhydrobiosis?
Anhydrobiosis is an adaptation where some aquatic invertebrates in temporary ponds lose almost all their body water and survive in a dormant state.
What adaptations do land animals have to reduce water loss?
Body coverings of most terrestrial animals help prevent dehydration.
What is the role of osmoregulatory energetics?
Osmoregulators must expend energy to maintain osmotic gradients.
What are transport epithelia?
Transport epithelia are epithelial cells specialized for moving solutes in specific directions.
What reflects an animal’s nitrogenous wastes?
An animal’s nitrogenous wastes reflect its phylogeny and habitat.
What are the forms of nitrogenous waste excretion?
Animals excrete nitrogenous wastes in different forms: ammonia, urea, or uric acid.
What are the key functions of most excretory systems?
Key functions include filtration, reabsorption, secretion, and excretion.
What are protonephridia?
Protonephridia are a network of dead-end tubules connected to external openings that excrete a dilute fluid.
What do metanephridia do?
Metanephridia consist of tubules that collect coelomic fluid and produce dilute urine for excretion.
What is the function of Malpighian tubules?
Malpighian tubules remove nitrogenous wastes from hemolymph in insects and function in osmoregulation.
What is the nephron?
The nephron is organized for stepwise processing of blood filtrate.
What occurs in the proximal tubule?
Reabsorption of ions, water, and nutrients takes place in the proximal tubule.
What happens in the descending limb of the Loop of Henle?
Reabsorption of water continues, driven by the high osmolarity of the interstitial fluid.
What occurs in the ascending limb of the Loop of Henle?
Salt but not water is able to diffuse from the tubule into the interstitial fluid.
What is the role of the collecting duct?
The collecting duct carries filtrate through the medulla to the renal pelvis and reabsorbs solutes and water.
How do mammals adapt their kidneys to diverse environments?
Variations in nephron structure and function equip the kidneys of different vertebrates for osmoregulation in various habitats.
What is the role of antidiuretic hormone (ADH)?
ADH regulates the release of water by increasing the number of aquaporin proteins in the membrane of collecting duct cells.
