Exam 42: Water and Electrolyte Balance in Animals

Freshwater fish reside in hypotonic environments.They do not drink water,and they excrete large volumes of hypotonic urine in an effort to osmoregulate.How do they obtain an adequate supply of electrolytes?

For filtration to take place through the fenestrated capillaries of the renal corpuscle,_____.

A potassium ion gradient is set up in the Malpighian tubules through an active transport process.As a result,potassium concentration is higher in the lumen of the tubules than in hemolymph.How would the potassium gradient affect water movement?

Which of the following most accurately describes selective permeability?

Gas exchange in insects takes place across the epithelium of the tracheae (a system of tubes).The tracheal system connects to the outside air by openings called spiracles.Muscles just inside each spiracle can control the opening to minimize water loss.What would happen if the muscles inside each spiracle were unable to function?

The filtrate formed in the renal corpuscle is analogous to the _____ formed in Malpighian tubules.

Why are the renal artery and renal vein critical to the process of osmoregulation in vertebrates?

What role do chloride cells play in osmoregulation of marine fish with bony skeletons?

The force driving simple diffusion is _____ while the energy source for active transport is _____.

Freshwater fish are hypertonic compared to their environment.To maintain homeostasis in this environment,they must _____.

Through studies on the Malpighian tubules,researchers found that K⁺ accumulated on the inner face of the tubule,against its concentration gradient.What can you infer about the mechanism of transport?

Hagfish (Eptatretus cirrhauts)are a jawless marine vertebrate that are isotonic with their environment and are considered to be osmoconformers.How might this interesting adaptation limit the habitat that the hagfish can tolerate?

One of the waste products that accumulates during cellular functions is carbon dioxide.It is removed via the respiratory system.What is another waste product that accumulates during normal physiological functions in vertebrates?

Water loss from insect surface is minimal due to which of the following structures?

Glucose is removed in the proximal convoluted tubules.Therefore,glucose is not expected to be found in a normal urine sample.However,glucose is found in the urine of diabetics.Why is this the case?

The loop of Henle dips into the renal cortex.This is an important feature of osmoregulation in terrestrial vertebrates because _____.

Salmon eggs hatch in freshwater.The fish then migrate to the ocean (a hypertonic solution)and,after several years of feeding and growing,return to freshwater to breed.How can these organisms make the transition from freshwater to ocean water and back to freshwater?

Sharks live in seawater.Their tissues are isotonic to seawater,but their concentrations of sodium ions,potassium ions,and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes.How is that possible?

If you are hiking through the desert for several days,one would pack which of the following to ensure proper hydration?

What is the function of the shark rectal gland?