What is the main buffer system of the ECF?

a. Protein buffer system

b. Carbonic acid–bicarbonate ion buffer system

c. Phosphate buffer system

d. None of the above

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

a. Potassium ions are responsible for the repolarization phase of the action potential.

Which of the following statements best describes the principle of mass balance?

a. The amount of a variable that is gained by the body through ingestion equals the amount that is lost from the body.

b. The body maintains a stable mass at all times.

c. The amount of each variable brought into the body must be balanced by all other variables.

d. The amount of a variable ingested is regulated by a positive feedback loop.

Your friend argues that all water conducts electricity, regardless of what it contains. You prepare three liquids to test this hypothesis: one with deionized water (with no solutes, only water molecules), one with 5% glucose in water, and one with 5% sodium chloride in water. Which of these solutions, if any, will conduct an electric current? Explain.

Elise Anderson is a 6-year-old girl who presents to the emergency department with a history of vomiting for the past 3 days. The nurse notices that her respiratory rate is abnormally low. What is the likely reason for this change in ventilation? Predict what Elise's arterial blood gas values would show.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

b. Insulin, aldosterone, and epinephrine stimulate the uptake of potassium ions into cells.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

c. Hyperkalemia tends to decrease the resting membrane potential and hyperpolarize excitable cells.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

d. Hypocalcemia causes neurons to become hyperexcitable, leading to potential tetanic contractions.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

e. Chloride ions are generally reabsorbed from the kidneys, along with bicarbonate ions.

The biggest source of metabolic acids in the body is:

a. lactic acid.

b. ketone bodies.

c. carbon dioxide.

d. uric acid.

Explain what happens to the pH of a buffered solution when hydrogen ions are added. Why does this happen?

Fill in the blanks: 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.

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.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

a. Respiratory acidosis is caused by hypoventilation.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

b. Renal compensation for acid-base disturbances begins within minutes, whereas respiratory compensation begins within several hours.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

c. Respiratory compensation for metabolic acidosis consists of hypoventilation.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

d. Renal compensation for metabolic alkalosis consists of reabsorption of hydrogen ions and secretion of bicarbonate ions.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

e. You would expect to find an elevated Pco₂ in arterial blood gas analysis of a patient with respiratory acidosis.

Which of the following statements correctly describe(s) the role of aldosterone?

a. Aldosterone triggers sodium ion and so water reabsorption.

b. Aldosterone triggers potassium ion secretion.

c. Aldosterone triggers hydrogen ion secretion.

d. Both a and b are correct.

e. All of the above are correct.

How does angiotensin-II help to restore fluid balance when a person is dehydrated?

How does an electrolyte differ from a nonelectrolyte?

A woman begins a diet and exercise regimen and loses 30 lb. Will her total body water increase, decrease, or stay the same? Why?

What do you think has happened to Elise's ECF volume and osmolarity over the past 3 days? Will this lead to a change in the volume of water in the cytosol of her cells? Explain.

What happens to the pH of a solution when hydrogen ions are added?

a. The pH increases.

b. The pH decreases.

c. The pH does not change.

d. The pH does not measure hydrogen ion concentration.

Explain how the amount of water in the body affects the concentration of ions and solutes in the ECF.

Ms. Johanssen is a patient in the hospital. The nurse examines her laboratory reports and notices that she has developed hyperkalemia and acidosis over the past several days. On closer examination of her medical chart, the nurse also sees that her physician recently doubled her dose of spironolactone, an aldosterone-blocking diuretic. How does this explain her laboratory findings?

As a percentage of body weight, the total body water tends to be higher in ________ and lower in ________ ​.

a. ​infants; men

b. women; men

c. men; infants

d. infants; women

Diabetic ketoacidosis is characterized by an increased level of ketone bodies, which causes metabolic acidosis. A patient in diabetic ketoacidosis will have an altered rate of ventilation. Will the patient be hyperventilating or hypoventilating? How will a change in the rate and depth of ventilation compensate for an acidosis that is metabolic in nature?

A laboratory printout of arterial blood gases indicates that a patient has an increased Pco₂ , decreased pH, and normal bicarbonate ion concentration. Is this patient in acidosis or alkalosis? Is the pH disturbance respiratory or metabolic in nature? Explain your reasoning. How long do you think the patient has had this pH disturbance? (Hint: Look at the bicarbonate ion concentration. What system controls the concentration of bicarbonate ions, and how quickly does it compensate for pH disturbances?)

Fill in the blanks. A cell in a/an ________ fluid will lose water, and a cell in a/an ________ fluid will gain water.