Osmoregulation and Excretion quiz Flashcards

Osmoregulation is the homeostatic mechanism that allows organisms to balance their solute concentration and deal with water loss.

The primary function of the excretory system is to eliminate waste from the body, which involves the loss of solutes and water.

The main organ involved in the excretory system is the kidney, which filters blood plasma and forms urine.

Ammonia is formed from the breakdown of proteins and nucleic acids, which contain nitrogen in their structures.

Ammonia is toxic because it needs to be heavily diluted to be safe in the body.

Urea is less toxic than ammonia and can be excreted with minimal water loss, making it suitable for organisms with limited water availability.

Uric acid is almost insoluble and can be excreted with minimal water loss, which is crucial for organisms in dry climates.

The nephron filters blood, reabsorbs valuable solutes and water, and secretes waste products to form urine.

The loop of Henle reabsorbs water and salt and helps maintain the osmotic gradients necessary for kidney function.

Selective permeability allows certain solutes to cross a membrane while preventing others, facilitating osmosis to balance solute concentrations.

Aquaporins are water channels that facilitate the efficient passage of water through the cell membrane.

ADH increases the permeability of the distal tubule and collecting duct to water, enhancing water reabsorption and reducing blood osmolarity.