26. Fluid and Electrolyte Balance, Acid Base Balance

Explain how emphysema and congestive heart failure can lead to acid-base imbalance.

Which of the following mechanisms is/are used by the kidneys to regulate the pH of the blood? Circle all that apply.

a. Hydrogen ions are secreted from the proximal and distal tubules and the collecting system.

b. Hydrogen ions are reabsorbed from the nephron loop.

c. New bicarbonate ions are formed from glutamine and carbon dioxide in the interstitial fluid that enters proximal tubule cells.

d. Bicarbonate ions can be secreted.

e. Bicarbonate ions are reabsorbed directly from the filtrate.

Write the missing names and molecular formulas for the following reactions between the carbonic acid–bicarbonate buffer system and the bicarbonate reserve.

a. ___

b. ___

c. ___

An increase in ventilation ________ the pH of the blood due to a/an ________ of carbon dioxide in the blood. A decrease in ventilation ________ the pH of the blood due to a/an ________ of carbon dioxide in the blood.

What is the difference between metabolic acidosis and respiratory acidosis? What can cause these conditions?

Two substances secreted into the proximal convoluted tubules in exchange for sodium ions are:

a. Ammonium ions

b. Bicarbonate

c. Calcium

d. Chloride

e. Hydrogen ions

f. Magnesium

g. Phosphate

h. Potassium

i. Sodium

j. Water

David’s grandfather suffers from hypertension. His doctor tells him that part of his problem stems from renal arteriosclerosis. Why would this cause hypertension?

What are the three major buffer systems in body fluids? How does each system work?

Explain the relationship of the following to renal secretion and excretion of hydrogen ions:

Plasma carbon dioxide levels

Phosphate

Sodium bicarbonate reabsorption

The control of blood pH by the kidneys during acidosis involves 

(a) The secretion of hydrogen ions and reabsorption of bicarbonate ions from the tubular fluid

(b) A decrease in the amount of water reabsorbed

(c) Hydrogen ion reabsorption and bicarbonate ion loss

(d) Potassium ion secretion

During a routine medical checkup, Shelby, a 26-year-old physiotherapy student, is surprised to hear that her blood pressure is 180/110. She also has a rumbling systolic and diastolic abdominal bruit (murmur) that is loudest at the mid-epigastric area. Her physician suspects renal artery stenosis (narrowing). She orders an abdominal ultrasound and renal artery arteriography, which confirm that Shelby has a small right kidney and the distal part of her right renal artery is narrowed by more than 70%. Her physician prescribes diuretics and calcium channel blockers as temporary measures, and refers Shelby to a cardiovascular surgeon. Explain the connection between Shelby's renal artery stenosis and her hypertension. Why is her right kidney smaller than her left? What would you expect Shelby's blood levels of K⁺, Na⁺, aldosterone, angiotensin II, and renin to be?

While visiting a foreign country, Milly inadvertently drinks some water, even though she had been advised not to. She contracts an intestinal disease that causes severe diarrhea. How would you expect her condition to affect her blood pH, urine pH, and pattern of ventilation?