Osmoregulation/Excretion Questions
Which of the following statements best describes the actions of the hormone ADH on the nephron? ADH causes the loop of Henle to increase urea reabsorption under conditions of dehydration. ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration. ADH causes the distal tubule to increase Na+ reabsorption when Na+ levels in the blood are low. ADH causes the proximal tubule to increase glucose reabsorption when the body's energy needs are high.
ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration.
Select the correct statement about osmoregulation. All marine invertebrates are stenohaline. The less the gradient between an animal's internal osmolarity and its external osmolarity (that of its surroundings), the higher the cost of osmoregulation. All osmoconformers are marine animals.
All osmoconformers are marine animals.
What is the driving force for the filtration of blood by the renal corpuscle?
Higher pressure in glomerular capillaries than in the surrounding Bowman's capsule.
In which region of the nephron is a steep osmotic gradient created?
Loop of Henle.
Which of the following represents the correct sequence of flow through the nephron? Distal tubule > loop of Henle > collecting duct > renal corpuscle > proximal tubule Renal corpuscle > loop of Henle > collecting duct > proximal tubule > distal tubule Renal corpuscle > distal tubule > proximal tubule > loop of Henle > collecting duct Renal corpuscle > proximal tubule > loop of Henle > distal tubule > collecting duct
Renal corpuscle > proximal tubule > loop of Henle > distal tubule > collecting duct
Which regions of the nephron function independently of hormonal control for the most part?
Renal corpuscle, proximal tubule, and loop of Henle.
Which of the following statements is true? Most humans have one kidney, which regulates water and electrolyte balance, removes nitrogenous wastes from the blood, and eliminates the wastes in the urine. The kidneys are paired organs that remove nitrogenous wastes from the urine. The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates. The kidneys regulate water and blood glucose in terrestrial vertebrates.
The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates.
What is the basic functional unit of the kidney?
The nephron.
Select the correct statement describing the osmolarity of mammalian urine. The osmolarity of mammalian urine may vary over time. The osmolarity of mammalian urine varies little between species Mammalian urine is always hyperosmotic to blood.
The osmolarity of mammalian urine may vary over time.
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?
Urea and trimethylamine oxide contribute to intra- and extracellular osmolarity in shark tissues.
Aldosterone is _____.
a steroid hormone that reduces the amount of fluid excreted in the urine
Glucose is removed from filtrate by _____.
active transport
Which of these is reabsorbed from filtrate? sodium chloride glucose water amino acids all of these
all of these
The outer part of the kidney is the _____.
cortex
The loop of Henle dips into the renal cortex. This is an important feature of osmoregulation in terrestrial vertebrates because _____.
differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient
To maintain homeostasis freshwater fish must _____.
excrete large quantities of water
A human who has no access to fresh water but is forced to drink seawater instead will _____.
excrete more water molecules than taken in, because of the high load of ion ingestion
The movement of substances out of the glomerulus and into Bowman's capsule is referred to as _____.
filtration
Which process in the nephron is LEAST selective? filtration secretion reabsorption active transport
filtration
After drinking alcoholic beverages, increased urine excretion is the result of _____.
inhibited secretion of antidiuretic hormone (ADH)
The transfer of fluid from the glomerulus to Bowman's capsule _____.
is mainly a consequence of blood pressure in the capillaries of the glomerulus
Compared to the seawater around them, most marine invertebrates are _____.
isoosmotic
A necropsy (postmortem analysis) of a marine sea star that died after it was mistakenly placed in fresh water would likely show that it died because _____.
it was so hypertonic to the fresh water that it could not osmoregulate
As filtrate moves down the loop of Henle, the surrounding interstitial fluid becomes _____ concentrated than the filtrate, so _____ leaves the filtrate.
more ... water
Which of these is the functional unit of a kidney?
nephron
The _____ are the major blood vessels transporting blood to the kidneys.
renal arteries
Urine formed by a kidney collects in the _____ before being drained from the kidney by the _____ and transported to the _____.
renal pelvis ... ureter ...urinary bladder
The movement of substances from the blood into the proximal tubule is known as _____.
secretion
Materials are returned to the blood from the filtrate by which of the following processes?
selective reabsorption
Increased antidiuretic hormone (ADH) secretion is likely after _____.
sweating-induced dehydration increases plasma osmolarity
The force driving simple diffusion is _____, while the energy source for active transport is _____.
the concentration gradient; ATP
The most abundant solute in urine is _____.
urea (and other nitrogenous wastes)