Question 1

What hormone stimulates the release of aldosterone?

Accepted Answer

Angiotensin II stimulates the release of aldosterone from the adrenal cortex, which helps regulate blood pressure by increasing sodium and water reabsorption in the kidneys.

Question 2

A patient is exhibiting several signs of acid -base imbalance. Blood tests reveal that blood pH is 7.3, and bicarbonate and carbon dioxide levels in blood are both low. What is the state of this patient?

Accepted Answer

The patient is experiencing metabolic acidosis, as indicated by the low blood pH (normal range is 7.35-7.45) and low bicarbonate levels. The low carbon dioxide levels suggest that the body is compensating through hyperventilation to remove CO2, which is a form of respiratory compensation.

Question 3

The role of a buffer is to

Accepted Answer

Buffers are designed to minimize changes in pH when acids or bases are added to a solution. They do this by absorbing excess hydrogen ions (H+) or donating them when their concentration falls, thereby stabilizing the pH of the solution.

Question 4

What hormone activates the cAMP second messenger system in principal cells of the distal tubules and collecting ducts?

Accepted Answer

ADH (Antidiuretic Hormone), also known as vasopressin, activates the cAMP second messenger system in principal cells of the distal tubules and collecting ducts, which plays a crucial role in water reabsorption.

Question 5

If hydrogen ions are added to a solution, the pH will

Accepted Answer

Adding hydrogen ions to a solution increases its acidity, which results in a decrease in the pH value.

Question 6

Which of the following is an effect of the transporters in the proximal tubules?

Accepted Answer

The transporters in the proximal tubules primarily facilitate the reabsorption of bicarbonate, helping to regulate the body's pH balance.

Question 7

Bicarbonate crosses the apical membrane of the proximal tubule by

Accepted Answer

Bicarbonate crosses the apical membrane of the proximal tubule primarily through conversion to carbon dioxide, which then diffuses into the cells.

Question 8

In the proximal tubule, hydrogen ions are transported into the filtrate by

Accepted Answer

In the proximal tubule, hydrogen ions are transported into the filtrate by both Na+/H+ countertransporters and H+ primary active transporters. This dual mechanism allows for the efficient regulation of pH and the reabsorption of bicarbonate.

Question 9

In order to compensate for a hyperventilation, the

Accepted Answer

During hyperventilation, the body loses carbon dioxide, leading to respiratory alkalosis. To compensate, the kidneys decrease the reabsorption of bicarbonate to help lower blood pH back to normal.

Question 10

What is the secondary defense against changes in pH that requires minutes to be activated?

Accepted Answer

Respiratory compensation is the secondary defense against changes in pH that can be activated within minutes by adjusting the rate of CO2 removal through breathing.

Question 11

What hormone increases water reabsorption by inserting aquaporin -2 proteins into the apical membrane of principal cells?

Accepted Answer

ADH (Antidiuretic Hormone), also known as vasopressin, increases water reabsorption in the kidneys by promoting the insertion of aquaporin-2 channels into the apical membrane of principal cells in the collecting ducts, allowing more water to be reabsorbed back into the bloodstream.

Question 12

When an increase in hydrogen ions remains after one hour, this will lead to a(n)

Accepted Answer

An increase in hydrogen ions in the body signals a state of acidosis. The kidneys respond to this by increasing the secretion of hydrogen ions into the urine to help restore the body's pH balance. This process helps to reduce the acidity of the blood.

Question 13

If hydrogen ions are taken out of a solution, the pH will

Accepted Answer

Removing hydrogen ions from a solution decreases its acidity, thereby increasing the pH value.

Question 14

Release of what hormone is stimulated by high levels of potassium?

Accepted Answer

Aldosterone release is stimulated by high levels of potassium in the blood. This hormone helps the kidneys to excrete potassium, thus helping to regulate its concentration in the body.

Question 15

A patient is exhibiting several signs of acid -base imbalance. Blood tests reveal that blood pH is 7.5, and bicarbonate and carbon dioxide levels in blood are both low. What is the state of this patient?

Accepted Answer

The patient is experiencing respiratory alkalosis, indicated by the elevated blood pH of 7.5. The low levels of bicarbonate and carbon dioxide suggest that the kidneys are attempting to compensate by excreting bicarbonate to lower the pH back to normal.

Question 16

Under severe acidic conditions, the proximal tubules can convert________into bicarbonate.

Accepted Answer

Glutamine is metabolized by the proximal tubules under severe acidic conditions to produce bicarbonate, which helps in the regulation of the body's pH balance.

Question 17

In the basolateral membrane of proximal tubular cells, bicarbonate is moved out of the cells by

Accepted Answer

Bicarbonate is moved out of the cells in the basolateral membrane of proximal tubular cells by both HCO3-/Cl- countertransporters and Na+/HCO3- cotransporters.

Question 18

Which of the following ions acts as a buffer to minimize changes in intracellular pH?

Accepted Answer

Phosphate ions act as a buffer in the intracellular fluid, helping to maintain a stable pH by neutralizing excess acids or bases.

Question 19

The most important buffer system in the extracellular fluid is

Accepted Answer

The bicarbonate buffer system is the most important buffer system in the extracellular fluid. It helps maintain the pH of the blood and other extracellular fluids by regulating levels of carbonic acid and bicarbonate.

Question 20

Respiratory compensation for changes in pH is originated by

Accepted Answer

Peripheral chemoreceptors detect changes in blood pH and signal the respiratory centers to adjust breathing rate and depth to compensate for pH changes.

Quiz 19: The Urinary System: Fluid and Electrolyte Balance