Explain how the chemical buffer systems resist changes in pH.

Mr. Jessup, a 55-year-old man, is operated on for a cerebral tumor. About a month later, he appears at his physician's office complaining of excessive thirst. He claims to have been drinking about 20 liters of water daily for the past week and says he has been voiding nearly continuously. A urine sample is collected and its specific gravity is reported as 1.001.

What is your diagnosis of Mr. Jessup's problem?

What connection might exist between his previous surgery and his present problem?

Explain why and how ECF osmolality is maintained.

For each of the following sets of blood values, name the acid-base imbalance (acidosis or alkalosis), determine its cause (metabolic or respiratory), decide whether the condition is being compensated, and cite at least one possible cause of the imbalance. Problem 1: pH 7.63; Pco₂ 19 mm Hg; Hco₃⁻ 19.5 mEq/L Problem 2: pH 7.22; Pco₂ 30 mm Hg; Hco₃⁻ 12.0 mEq/L

Explain why and how total body sodium content, ECF volume, and blood pressure are jointly regulated.

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

Plasma carbon dioxide levels

Phosphate

Sodium bicarbonate reabsorption

Describe the role of the respiratory system in controlling acid-base balance.