Question

1.   In the proximal tubule under normal conditions, 50% of glucose is reabsorbed back into the peritubular capillaries.
a.   true
b.   false

2.   The transport maximum (Tmax) is the upper limit of reabsorption of glucose and amino acids due to the saturation of carrier systems that return these substances back to the blood.
a.   true
b.   false

3.   Which of the following is an effect of aldosterone? MIGHT BE C***
a.   excretion of sodium ions
b.   conservation of potassium ions
c.   conservation of sodium ions
d.   all are correct

4.   Some hydrogen ions secreted into the collecting duct are buffered. These buffers are
a.   bicarbonate buffers
b.   ammonia (NH3)
c.   phosphate buffers
d.   all of the above

5.   The glomerular filtration rate average in an adult male is 125 ml/min. (Might be F)
a.   true
b.   false

Answer 1

1.true

The high volume reabsorption occurs at the proximal convoluted tubules ,it absorbs 50-60 % of the glomerular filtrate in the normal condition. The proximal convoluted tubules reabsorbs the glucose present in the glomerular filtrate and reabsorbed back in the peritubular Capillaries.

2. False

The transport maximum (Tmax) is the threshold after which the increase in the concentration of the molecules doesn't facilitate the movement of the molecules through the cell membrane. After attaining the transport maximum,some of the channel or carrier system gets saturated that doesn't allow the reabsorption through the kidney tubules and will be excreted via urine.

3.c.   conservation of sodium ions

The aldosterone hormone released from the adrenal cortex functions in reabsorption of salt and water from kidney tubules into the blood in order to increase the volume of blood,maintains the salt concentration and blood pressure.Thus, it conserve the sodium and in turn causes the release of potassium through urine flow.

4  all of the above

Secretion of free hydrogen ions (by the action of carbonic anhydrase) occurs in the collecting duct and distal tubules.The secretion of the hydrogen occurs due to the generation of bicarbonate ions that travels back to the extracellular fluid.The inorganic phosphate and ammonia absorbs the free hydrogen and secretes into the collecting tubules, thus considered as the urinary buffers.

5.True

The glomerular filtration rate average in the adult male is 90 and above (125 ml/min is the normal range for male ). The females have the slightly less GFR compare to males .