Renal Compensation

Question 1

Renal compensation is

Answer 1

A change in the rates of hydrogen ion and HCO3 secretion or reabsorption by the kidneys in response to changes in plasma pH

Question 2

Under normal conditions, the body generates enough organic and fixed acids to add about

Answer 2

100 mEq of H to the ECF each day

Question 3

To maintain acid base balance

Answer 3

An equivalent number of hydrogen ions must be excreted in urine.
The kidneys assist the lungs by eliminating any CO2 that enters the renal tubule’s during filtration or diffuses into the tubular fluid as it travels toward the renal pelvis.

Question 4

Where are hydrogen ions secreted into the tubular fluid

Answer 4

Along the proximal convoluted tubule’s,
the distal convoluted tubule,
And the collecting system

Question 5

The ability to eliminate a large number of hydrogen ions in a normal volume of urine depends on

Answer 5

The presence of buffers in the urine

Question 6

If the tubular fluid lacked buffers to absorb the hydrogen ions what happens

Answer 6

The kidneys could secrete less than 1% of the acid produced each day before the pH reached this limit. Under these conditions the kidneys would have to produce 1000 L of urine each day to keep pace with the generation of hydrogen ions in the body

Question 7

Why buffers in tubular fluid are extremely important

Answer 7

Because they keep the pH high enough for hydrogen secretion to continue. Metabolic acids are constantly generated.
Without these buffering mechanisms the kidneys could not maintain homeostasis.

Question 8

What are the three major buffering mechanisms that stabilize the pH of tubular fluid

Answer 8

1. Carbonic acid bicarbonate buffer system 2. phosphate buffer system
2. ammonia buffer system

Question 9

—– puts components of the carbonic acid bicarbonate buffer system and the phosphate buffer system into the filtrate.

Answer 9

Glomerular filtration

Question 10

—-(mainly of the PCT) generate ammonia

Answer 10

Tubule cells

Question 11

Secretion of hydrogen ions relies on

Answer 11

Carbonic anhydrase activity within tubular cells.

Question 12

A hydrogen ions generated within tubular cells may be pumped into the lumen in exchange for

Answer 12

Sodium ions, individually or together with chloride ions.

Question 13

The net result is the secretion of hydrogen ions, accompanied by the removal of

Answer 13

CO2 and the release of sodium bicarbonate into the ECF

Question 14

The generation of ammonia with in the tubules

Answer 14

1. As tubule cells use the enzyme glutaminase to break down the amino acid glutamine, amino groups are released as either ammonium ion’s NH4 or ammonia NH3.
2. The ammonium ions NH4 are transported into the lumen in exchange for NA in the tubular fluid.
3. The ammonia NH3, which is highly volatile and toxic to cells,rapidly diffuse into the tubular fluid. There it reacts with a hydrogen ion, forming NH4