You just received a freshwater aquarium as a gift and decide to add more fish. When you get to the pet store, you find that the most beautiful fish are saltwater animals, but you decide to buy them anyway. What will happen when you put your expensive saltwater fish in your freshwater aquarium?
The cells of the fish will take up too much water, and the fish will die.
The fish will dehydrate and die.
The fish will get larger more quickly in the healthier conditions of fresh water.
In the better conditions of fresh water, the fish adjust and do better than in salt water.
Nothing: the fish will live normally.
answer
The cells of the fish will take up too much water, and the fish will die.
question
Terrestrial animals are _____.
osmoregulators that must obtain water from the environment
likely to have the same problems with osmoregulation as do freshwater fish
usually nocturnal
obligated to protect their eggs from drying with water-resistant shells
either arthropods or vertebrates
answer
osmoregulators that must obtain water from the environment
question
Birds, insects, and many reptiles excrete nitrogenous waste in the form of uric acid, which _____.
is not very toxic compared to other nitrogenous wastes, but requires the loss of a lot of water with its excretion
reduces water loss compared to other nitrogenous wastes, but requires more metabolic energy to produce
reduces energy use compared to other nitrogenous wastes, but is highly toxic to animals that produce it
is much more soluble in water than other nitrogenous wastes, but is energetically costlier than other nitrogenous wastes to synthesize
reduces water loss compared to other nitrogenous wastes, but is highly toxic
answer
reduces water loss compared to other nitrogenous wastes, but requires more metabolic energy to produce
question
Freshwater fish excrete nitrogenous wastes as _____.
proteins
ammonia
guano
urea
uric acid
answer
ammonia
question
Urine formed by a kidney collects in the _____ before being drained from the kidney by the _____ and transported to the _____.
urethra ... urinary bladder ... ureter
renal pelvis ... medulla ... cortex
renal pelvis ... ureter ...urinary bladder
renal pelvis ... urethra ... urinary bladder
ureter ... renal pelvis ... urinary bladder
answer
renal pelvis ... ureter ...urinary bladder
question
Filtrate is formed as fluid is forced through the walls of the glomerulus and, initially, collects in the structure indicated by the letter
Question #3
A
B
C
D
E
answer
B
question
The _____ are the major blood vessels transporting blood to the kidneys.
pulmonary arteries
glomerulus
renal arteries
renal veins
venae cavae
answer
renal arteries
question
The outer part of the kidney is the _____.
medulla
nephron
lacteal
cortex
Bowman's capsule
answer
cortex
question
Which of these is the functional unit of a kidney?
neuron
villi
nephron
alveolus
osteon
answer
nephron
question
An appropriate group of animals to examine to observe a Malpighian tubule would be _____.
the annelids
the flatworms
the birds
the amphibians
the insects
answer
the insects
question
As a result of the non-selectivity of the kidney's filtration of small molecules, _____.
useful substances must be selectively reabsorbed
the proportions of all the substances in the blood are the same as in the urine
urine is always much less concentrated than blood
the kidneys have little control over body fluid composition
many useful substances are lost in the urine
answer
useful substances must be selectively reabsorbed
question
Which arrow indicates the direction of a gradient of increasing solute concentration in the interstitial fluid surrounding a nephron?
Question #12
A only
B only
B and C
C and D
A and D
answer
A Only
question
Glucose is removed from filtrate by _____.
secretion
diffusion
dialysis
active transport
osmosis
answer
active transport
question
The movement of substances out of the glomerulus and into Bowman's capsule is referred to as _____.
secretion
reabsorption
active transport
ion pumping
filtration
answer
filtration
question
The movement of substances from the blood into the proximal tubule is known as _____.
filtration
dialysis
secretion
reabsorption
none of these
answer
secretion
question
Which of these is reabsorbed from filtrate?
sodium chloride
glucose
water
amino acids
all of these
answer
all of these
question
As filtrate moves down the loop of Henle, the surrounding interstitial fluid becomes _____ concentrated than the filtrate, so _____ leaves the filtrate.
more ... urea
less ... urea
more ... water
less ... water
less ... water and urea
answer
more ... water
question
The most abundant solute in urine is _____.
glucose
water
plasma proteins
sodium chloride
urea (and other nitrogenous wastes)
answer
urea (and other nitrogenous wastes
question
Label the diagram of the kidney and nephron below.
Drag the labels to their appropriate locations on the diagram below. Labels can be used once, more than once, or not at all.
answer
The nephron is the functional unit of the kidney, meaning that filtrate is processed in the nephrons. Nephrons are positioned in the renal cortex and can extend into the renal medulla. A nephron consists of a glomerulus and a long tubule that includes Bowman's capsule, the proximal tubule, the loop of Henle, and the distal tubule. Filtration occurs at the glomerulus-Bowman's capsule interface, sometimes called the renal corpuscle. The filtrate then travels through the rest of the nephron and drains into the collecting duct. The filtrate, now called urine, exits the kidney through a ureter that drains into the urinary bladder. Finally, the urine is expelled from the body through the urethra.
question
The kidneys are regulated by hormones such as antidiuretic hormone (ADH) and aldosterone. These hormones are secreted in response to changes in the animal's internal water and salt balance. For example, sweating or blood loss can disrupt water and/or salt balance in the body, leading to a hormonal response that returns the system to homeostasis. Mechanisms for adjusting blood volume or osmolarity include increasing water and/or sodium reabsorption in the nephrons and collecting ducts.
How do the following stimuli affect water and sodium (Na+) reabsorption in the kidneys?
answer
Antidiuretic hormone (ADH) and aldosterone are two of the hormones that help to regulate blood osmolarity, blood pressure, and blood volume by acting on the kidney.
ADH is released from the posterior pituitary gland in response to increased blood osmolarity. Dehydration, sweating, and eating salty foods can all cause blood osmolarity to rise. To counteract that change, ADH acts on the distal tubules and collecting ducts, causing them to become more permeable to water. As a result, water is reabsorbed, lowering blood osmolarity, concentrating the urine, and reducing urine volume.
question
The kidneys of terrestrial mammals conserve water in the body by concentrating urine. The osmolarity of human blood is 300 mOsm/L, but human urine is generally about 1200 mOsm/L. The loop of Henle and the collecting duct are instrumental in maintaining osmotic gradients that make the concentration of urine possible.
Complete the diagram below using the following steps:
answer
Water is reabsorbed in the kidney because of the osmotic gradient established in the interstitial fluid. The osmolarity of the interstitial fluid increases deeper into the medulla. As a result, water diffuses out of the descending limb of the loop of Henle and out of the collecting duct, flowing from areas of lower osmolarity in the filtrate to areas of higher osmolarity in the interstitial fluid. This water diffuses into blood vessels surrounding the nephron, called the vasa recta, returning to the bloodstream and therefore not diluting the osmotic gradient.
The osmotic gradient in the interstitial fluid is maintained mostly by NaCl and urea. In the thin portion of the ascending limb of the loop of Henle, NaCl diffuses out of the nephron. In the thick upper portion of the ascending limb, NaCl is actively transported out of the nephron. (The ascending limb is impermeable to water, which helps maintain high osmolarity in the interstitial fluid.) Urea diffuses out of the lower portion of the collecting duct and is responsible for the high osmolarity in the inner medulla.
After traveling through the nephron and the collecting duct, urine is more concentrated than other body fluids and excretes urea and other wastes with a minimal loss of water. The ability of mammalian kidneys to conserve water in this way is a key terrestrial adaptation.
question
Under the influence of antidiuretic hormone (ADH), _____ is produced.
urine containing more glucose
bloody urine
urine containing a lower concentration of urea
more concentrated urine
less concentrated urine
answer
more concentrated urine
question
Antidiuretic hormone (ADH) makes the _____ permeable to water.
ascending portion of the loop of Henle
collecting duct
Bowman's capsule
proximal tubule
descending portion of the loop of Henle
answer
collecting duct
question
Which of the following statements is true?
The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates.
The kidneys are paired organs that remove nitrogenous wastes from the urine.
The kidneys regulate water and blood glucose in terrestrial vertebrates.
Most humans have one kidney, which regulates water and electrolyte balance, removes nitrogenous wastes from the blood, and eliminates the wastes in the urine.
answer
The kidneys are paired organs that regulate water and electrolyte balance in terrestrial vertebrates.
question
What is the basic functional unit of the kidney?
The Malpighian tubule.
The nephron.
The medulla.
The renal corpuscle.
answer
The nephron.
question
In which region of the nephron is a steep osmotic gradient created?
Collecting duct.
Distal tubule.
Proximal tubule.
Loop of Henle.
answer
Loop of Henle.
question
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 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.
ADH causes the distal tubule to increase Na+ reabsorption when Na+ levels in the blood are low.
answer
ADH causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration.
question
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 > proximal tubule > loop of Henle > distal tubule > collecting duct
Renal corpuscle > distal tubule > proximal tubule > loop of Henle > collecting duct
Renal corpuscle > loop of Henle > collecting duct > proximal tubule > distal tubule
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.
The presence of microvilli.
The diffusion of small solutes such as urea down a concentration gradient.
The presence of large pores in the glomerular capillaries and filtration slits.
answer
Higher pressure in glomerular capillaries than in the surrounding Bowman's capsule.
question
Which regions of the nephron function independently of hormonal control for the most part?
Proximal tubule, loop of Henle, and distal tubule.
Renal corpuscle, proximal tubule, and loop of Henle.
Distal tubule and collecting duct.
Renal corpuscle and collecting duct.
answer
Renal corpuscle, proximal tubule, and loop of Henle.
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