A 75 year old man was

moderately dehydrated following an abdominal operation. His mean arterial blood

pressure was at the lower limit of normal. The anaesthetist estimated that his

total peripheral resistance was increased in order to compensate for the hypovolaemia.  The junior doctor on the team prescribed a

non-steroidal anti-inflammatory (NSAID) drug (PGE 2 inhibitor) for pain relief.

Two days later, the patient’s creatinine clearance was found to be markedly

decreased.

Which is the most likely

mechanism responsible for the drop in creatinine clearance?

A 55 year old man attends

for a routine check-up with his General Practitioner. Routine tests reveal the

presence of a moderate amount of protein in his urine.

Which of the following

processes is likely to have contributed to this finding?

A research physiologist

decides to use a marker to measure the volume of total body water in a

volunteer.

Which of the following

substances would be most appropriate?

Under normal conditions, 100% of the filtered load of

glucose is reabsorbed by the renal tubule.

Which part of the tubule lumen would be expected to

have the highest concentration of glucose under normal conditions?

A 65 year old man received 2 L of 0.9% saline (normal

saline) following a minor surgical procedure. This resulted in increased atrial

filling and distension.

Which of the following is most likely to be secreted in response?

The following data were collected from a healthy volunteer before and after an intervention. Assume that plasma osmolarity and glomerular filtration rate remain constant.

                                                                                Before             After

Urine osmolarity (mOsm/L)                                 900                         250                  

Urine flow rate (ml/min)                                      0.65                        2.3

Fractional clearance of sodium                            1%                          1%

Fractional clearance of potassium                       1%                          1%

The following data were collected from a healthy volunteer before and after an intervention. Assume that plasma osmolarity and glomerular filtration rate remain constant.

                                                                                Before             After

Urine osmolarity (mOsm/L)                                 900                         250                  

Urine flow rate (ml/min)                                      0.65                        2.3

Fractional clearance of sodium                            1%                          1%

Fractional clearance of potassium                       1%                          1%

Which of the following interventions would best account for the observed changes?

A researcher is studying

the interaction of the substance para-aminohippuric acid (PAH) with the kidney.

She injects a volunteer with the substance.

Which of the following can

be determined after calculating the clearance of PAH?

As part of an experimental study a volunteer agrees to

have 10g mannitol injected intravenously. After sufficient time for

equilibration, blood is drawn and the concentration of mannitol in the plasma

is found to be 65 mg / 100 ml. Urinalysis reveals 10% of the mannitol had been

excreted into the urine during this time period.

What is the approximate (to the nearest litre (L))

extracellular fluid volume of this volunteer?

You are given the following

measurements:

Glomerular hydrostatic pressure = 44 mmHg

Bowman’s capsule hydrostatic pressure = 9 mmHg

Osmotic pressure of plasma = 28 mmHg

Osmotic pressure of tubular fluid = 0 mmHg

What is the net filtration

pressure at the glomerulus?