Block 6 Renal Physiology Part 2

Based on the given figure, point D represents acute respiratory acidosis. This can be inferred because point D falls below the normal range of arterial pH and above the normal range of arterial PCO2. Acute respiratory acidosis occurs when there is an increase in arterial PCO2, leading to a decrease in arterial pH. Therefore, point D represents a condition of elevated arterial PCO2 and decreased arterial pH, indicating acute respiratory acidosis.

Hyperventilation is the act of breathing rapidly and deeply, leading to excessive elimination of carbon dioxide from the body. This causes a decrease in the concentration of carbon dioxide in the blood, which leads to respiratory alkalosis. Respiratory alkalosis is a condition characterized by a higher pH level in the blood. It is considered a compensation for metabolic acidosis, which is a condition characterized by a lower pH level in the blood due to an excess of acid or a loss of bicarbonate. Therefore, option b is the correct answer.

Chronic diarrhea can lead to metabolic acidosis because the loss of fluids and electrolytes in the stool can disrupt the balance of acids and bases in the body. This can result in an accumulation of acid in the blood, leading to a decrease in pH and an acidic environment.

The given electrolyte values show a low level of bicarbonate (HCO3-), which is an indicator of metabolic acidosis. In metabolic acidosis, there is an excess of acid or a loss of bicarbonate, leading to a decrease in the pH of the blood. The low bicarbonate level in this patient's values supports the diagnosis of metabolic acidosis.

An elevated arterial pH, elevated arterial Pco2, and elevated arterial [HCO3-] indicate a condition called metabolic alkalosis. In metabolic alkalosis, there is an excess of bicarbonate ions in the blood, leading to an increase in pH. The elevated arterial Pco2 suggests that the respiratory system is compensating for the alkalosis by retaining carbon dioxide. This helps to decrease the pH and bring it back towards normal.

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Increased formation of ammonia from glutamine is a compensation for respiratory acidosis because it helps to increase the excretion of hydrogen ions (H+) in the urine. When the body is in respiratory acidosis, there is an excess of carbon dioxide (CO2) in the blood, leading to an increase in the production of carbonic acid (H2CO3) and hydrogen ions. The increased formation of ammonia from glutamine helps to buffer these excess hydrogen ions by combining with them to form ammonium ions (NH4+), which can be excreted in the urine, thereby reducing the acidosis.

Aldosterone stimulates the H+-ATPase on intercalated cells, which leads to increased secretion of hydrogen ions (H+) into the urine and reabsorption of bicarbonate ions (HCO3-) in the kidneys. This results in an excess of bicarbonate in the blood, leading to metabolic alkalosis. Therefore, the correct answer is b. Metabolic alkalosis.

During acidosis, the body tries to buffer the excess H+ ions by increasing the levels of phosphate in the plasma and ultrafiltrate. However, this increased buffering by phosphate can lead to a detrimental consequence of bone fragility. This is because phosphate is an important component of bone mineralization, and when it is used to buffer H+ ions, it can lead to a loss of phosphate from the bones, weakening them and increasing the risk of fractures.

Based on the figure, point C represents metabolic acidosis. This is because point C is located in the lower left quadrant of the graph, indicating a low arterial pH and a high arterial PCO2. In metabolic acidosis, there is an excess accumulation of acid or a loss of bicarbonate, resulting in a decrease in pH and an increase in PCO2. Therefore, point C aligns with the characteristics of metabolic acidosis.

Acetazolamide is a medication that is commonly used to treat glaucoma and altitude sickness. It works by inhibiting the enzyme carbonic anhydrase, which plays a role in the production of bicarbonate ions. By inhibiting this enzyme, acetazolamide reduces the production of bicarbonate ions, leading to a decrease in the blood pH and the development of metabolic acidosis. Severe vomiting can also lead to metabolic acidosis by causing a loss of bicarbonate ions through the stomach. High altitude and tracheal obstruction do not directly cause metabolic acidosis. Excessive ingestion of antacids can actually lead to metabolic alkalosis, not acidosis.

The patient suffering from an anxiety-induced panic attack would have a decreased pH, decreased [HCO3-], and an increased PCO2. Among the given options, option c is the only one that matches these criteria. The pH is 7.52 (decreased), the [HCO3-] is 20 (decreased), and the PCO2 is 25 (increased). Therefore, the patient in option c is likely suffering from an anxiety-induced panic attack.

The patient with the values of pH 7.15, [HCO3-] 4, and PCO2 10 has a low pH and low bicarbonate levels, indicating metabolic acidosis. In response to this acidosis, the patient compensates by hyperventilating, resulting in a low PCO2 value. This is consistent with respiratory compensation, where the body tries to decrease the PCO2 levels by increasing ventilation. Therefore, the correct answer is b.

In chronic respiratory acidosis, there is an accumulation of carbon dioxide in the blood due to impaired lung function. This leads to a decrease in arterial pH, resulting in acidosis. Over time, with proper treatment and management of the underlying condition, the lungs may regain some function, allowing for better elimination of carbon dioxide. As a result, the arterial pH would be expected to return to a normal value.

Metabolic alkalosis is not associated with bone loss in kidney failure. Kidney failure can lead to impaired conversion of vitamin D, impaired intestinal calcium absorption, impaired calcium reabsorption, and increased plasma phosphate concentration, all of which contribute to bone loss. However, metabolic alkalosis does not directly contribute to bone loss in this context.

The patient with a pH of 7.35, [HCO3-] of 44, and PCO2 of 85 is suffering from chronic obstruction of the airways. This can be determined by looking at the PCO2 value, which is elevated, indicating that the patient is retaining carbon dioxide due to impaired ventilation. This is a characteristic finding in patients with chronic obstructive pulmonary disease (COPD), a condition that causes obstruction of the airways and leads to impaired gas exchange.

In a patient with renal shutdown, the kidneys are unable to effectively remove waste products and maintain the balance of electrolytes and acid-base levels in the body. As a result, there is a buildup of acidic waste products in the blood, leading to a decrease in pH.

Aspirin overdose leads to a mixed acid-base disorder because it causes metabolic acidosis by producing excess acid. Additionally, aspirin acts as a stimulant of the respiratory center, leading to hyperventilation and respiratory alkalosis. This means that the body eliminates more carbon dioxide, which decreases the levels of carbonic acid in the blood and causes alkalosis. Therefore, option a is the correct answer.

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Endothelin is believed to play a role as an intrarenal vasoconstrictor. Endothelin is a potent vasoconstrictor that is produced by endothelial cells and acts on smooth muscle cells in blood vessels. It plays a role in regulating blood flow and blood pressure within the kidneys. The vasoconstrictive effects of endothelin can reduce blood flow to the kidneys, potentially leading to decreased kidney function. Therefore, endothelin is considered to be an important factor in the regulation of renal blood flow and renal function.

Nephrosis is a condition characterized by excessive urinary protein loss. When the liver is unable to compensate for this loss, the plasma volume increases. This increased plasma volume leads to increased capillary pressure, which in turn causes fluid to leak out of the capillaries and into the surrounding tissues, resulting in edema. Therefore, the correct answer is "because of the increased plasma volume and resulting increased capillary pressure."

The tumor is putting pressure on the left renal artery, causing it to be partially occluded. This would result in a decrease in blood flow to the left kidney. The decrease in blood flow to the kidney would activate the renin-angiotensin-aldosterone system, leading to an increase in plasma renin levels and subsequently an increase in plasma aldosterone levels. Increased aldosterone levels would cause sodium and water retention, leading to an increase in total peripheral resistance. However, the tumor's effect on the left renal artery would not directly affect heart rate.

Based on the given information, the patient with a pH of 7.56, [HCO3-] of 48, and PCO2 of 55 is experiencing respiratory alkalosis. This is indicated by the high pH and PCO2 levels. Anorexia is not directly related to the acid-base balance in the body, so it cannot be determined solely based on the given information. Therefore, the correct answer cannot be determined.

Tidal volume refers to the amount of air that is inhaled and exhaled during normal breathing. In the case of metabolic alkalosis, which is a condition characterized by an increase in blood pH, the body compensates by decreasing the respiratory rate and increasing the tidal volume. This adjustment helps to retain more carbon dioxide in the body, which can lower the blood pH and counteract the alkalosis. Therefore, an increase in tidal volume is a response to metabolic alkalosis.

Based on the given information, the individual is producing 1 L of urine per day. The urine HCO3- concentration is 5 mEq/L, urinary ammonium is 20 mEq/L, and titratable acid is 10 mEq/L. To determine the amount of new HCO3- being made daily, we subtract the urinary HCO3- concentration from the sum of urinary ammonium and titratable acid. Therefore, 20 mEq/L + 10 mEq/L - 5 mEq/L = 25 mEq/L. Since the individual is producing 1 L of urine per day, the amount of new HCO3- being made daily is 25 mEq/L * 1 L = 25 mEq. Thus, the correct answer is c. making 35 mEq new HCO3- daily.

Pyelonephritis is an infection of the kidneys that can lead to inflammation and damage to the renal tubules. This can impair the kidneys' ability to concentrate urine, resulting in a dilute urine. However, it does not typically affect the ability to generate a concentrated urine. Therefore, the patient is most likely to have problems generating a concentrated but not a dilute urine with pyelonephritis.

During anuria, there is a complete absence of urine production, leading to the buildup of waste products and electrolytes in the extracellular fluid (ECF). Phosphate (HPO4-) is one of the electrolytes that can accumulate in the ECF due to the lack of excretion through urine. Therefore, with anuria lasting 3-5 days, the concentration of phosphate (HPO4-) in the ECF will likely increase.