1b Kidney Function

Question 1

If a patient is dehydrated, the filtrate present in which of these areas will have the highest osmolarity?

Answer 1

Tip of the loop of henle

Question 2

Why will a patient with hepatic cirrhosis have urine with a high osmolarity?

Answer 2

Due to abnormally high water and salt retention

Question 3

An athlete after finishing their London Marathon run drank 2L of distilled water. What will happen to their plasma osmolarity?

Answer 3

Decrease in plasma osmolarity

Question 4

The increase in plasma concentration of which solute will have no effect on ADH production?

Urea
Glucose
Salt
Ethanol

Answer 4

Urea

Question 5

Sodium excretion is very limited (less than 1% of filtered load) and several mechanisms exist to tightly regulate it. Increasing sodium excretion reduces water retention. Potassium excretion can vary over a very large range (from 1 to 80% of filtered load). Why doesn’t this variability in potassium excretion have a marked effect on water balance?

Answer 5

The amount of potassium in the plasma and extracellular is much lower than the amount sodium so that variations in this amount are insufficient to have a marked effect on water balance.

Question 6

Why do most diuretics increase potassium excretion?

Answer 6

The increase in flow rate is detected in the collecting duct and directly stimulates potassium excretion.

The increased tubular flow rate stimulates the primary cilium, which increases PDK 1 -> this increases the calcium concentration inside the cell which increases the openness of the apical potassium channels leading to more POTASSIUM EXCRETION

Question 7

Ms S, a 25-year-old woman while trekking the Himalayas develops symptoms of dizziness and pain. Following data was collected for her: Blood pH = 7.6, [HCO3-] = 16mEq/L, PCO2 = 25mmHg. Identify her acid-base disorder.
[Normal values: Blood pH = 7.4, [HCO3-] = 24mEq/L, PCO2 = 40mmHg]

Answer 7

Respiratory Alkalosis

Question 8

Ms L, a 25-year-old healthy woman on her holiday develops stomach infection with nausea and vomiting. Following data was collected for her: Blood pH = 7.1, [HCO3-] = 16mEq/L, PCO2 = 30mmHg. Identify the compensatory mechanism being used by her body. [Normal values: Blood pH=7.4, [HCO3-] = 24mEq/L, PCO2 = 40mmHg]

Answer 8

Respiratory compensation – Hyperventilation

Question 9

Ms J, a 25-year-old woman with a history of asthma, on her holiday develops stomach infection with diarrhoea. Following data was collected for her: Blood pH = 7.1, [HCO3-] = 16mEq/L, PCO2 = 45mmHg. Identify her acid-base disorder.
[Normal values: Blood pH = 7.4, [HCO3-] = 24mEq/L, PCO2 = 40mmHg]

Answer 9

Mixed Acidosis