Question

During countercurrent multiplication, water is reabsorbed into the blood from the descending limb of the loop of Henle because

a. NaCl is transported out of the ascending limb

b. It is co-transported with Na+

c. Na+ is reabsorbed from the proximal convoluted tubule

d. Glucose is reabsorbed by the proximal convoluted tubule

e. Cl- is secreted into the distal convoluted tubule

2. A low salt (NaCl) diet is recommended for individuals with high blood pressure because

a. salt is the main cause of high blood pressure, so it needs to be consumed in low amounts.

b. extra Na+ in the diet causes blood vessels to stiffen which raises blood pressure over time

c. water follows Na+ and excess salt in the body will increase water retention and blood volume and thus, blood pressure

d. excess salt will force water into cells which may interrupt cell function or cause damage

e. excess salt will accumulate in blood vessels and block blood flow to tissues

3. To compensate for a state of acidosis, the kidney will

a. Increase H+ reabsorption to the blood

b. Slow metabolic production of acids like CO2

c. Slow the production of bicarbonate by tubular epithelial cells

d. Inhibit reabsorption of bicarbonate to the blood

e. Secrete H+ to the filtrate to be excreted

4. Chemical buffers

a. Only buffer the intracellular fluid and urine.

b. Eliminate excess acids or bases from the body.

c. Induce hypoventilation in response to abnormal carbon dioxide levels in the blood.

d. Only buffer the extracellular fluid.

e. temporarily tie up carbon dioxide or hydrogen ions until the lungs or kidneys are able to expel them from the body.

Answer 1

1. a. NaCl is transported out of the ascending limb

Explanation: In counter-current multiplication, salts are absorbed in ascending loop of Henle, leading to hypertonicity of the interstitial fluid, this exerts osmotic pressure to cause absorption of water from the descending limb of loop of henle.

2. c. water follows Na+ and excess salt in the body will increase water retention and blood volume and thus, blood pressure

Explanation: Increase salt consumption results in increased osmolarity of the blood which in turn causes retention of water and fluid in the vascular compartment leading to increase in blood volume and blood pressure.

3. e. Secrete H+ to the filtrate to be excreted

Explanation: Acidosis is due to increase in H+ ion level of the blood. to compensate acidosis, kidney excrete more H+ and reabsorb more bicarbonate to bring pH back to normal range.

4. e. temporarily tie up carbon dioxide or hydrogen ions until the lungs or kidneys are able to expel them from the body.