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A&P II Chapter 25 Study Guide – Fluid, Electrolyte, and Acid-Base Balance

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Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Q1. How does an electrolyte differ from a nonelectrolyte?

Background

Topic: Electrolytes vs. Nonelectrolytes

This question tests your understanding of the chemical properties of substances in solution, specifically their ability to conduct electricity.

Key Terms:

  • Electrolyte: A substance that dissociates into ions when dissolved in water, allowing the solution to conduct electricity.

  • Nonelectrolyte: A substance that does not dissociate into ions in solution and therefore does not conduct electricity.

Step-by-Step Guidance

  1. Recall that electrolytes, such as salts, acids, and bases, break apart into charged particles (ions) in water.

  2. Think about how ions in solution allow for the movement of electrical current.

  3. Contrast this with nonelectrolytes, such as glucose or urea, which dissolve in water but do not form ions.

  4. Consider how the presence or absence of ions affects the solution's ability to conduct electricity.

Try explaining the difference in your own words before checking the answer!

Q2. What happens to the pH of a solution when hydrogen ions are added?

Background

Topic: pH and Hydrogen Ion Concentration

This question tests your understanding of the relationship between hydrogen ion concentration and pH.

Key Terms and Formula:

  • pH: A measure of the hydrogen ion concentration in a solution.

  • Formula:

Step-by-Step Guidance

  1. Recall that pH is inversely related to the concentration of hydrogen ions ().

  2. Think about what happens mathematically to the pH value when increases.

  3. Review the answer choices and eliminate those that do not fit the relationship between pH and .

Try reasoning through the relationship before checking the answer!

Q3. As a percentage of body weight, the total body water tends to be higher in ________ and lower in ________.

Background

Topic: Body Water Distribution

This question tests your knowledge of how body water content varies with age and sex.

Key Concepts:

  • Infants, men, and women have different percentages of body water due to differences in fat content and muscle mass.

Step-by-Step Guidance

  1. Recall which group (infants, men, or women) typically has the highest percentage of body water.

  2. Consider which group has the lowest percentage and why (think about fat vs. muscle content).

  3. Match your reasoning to the answer choices provided.

Try to fill in the blanks before checking the answer!

Q4. Fill in the blanks. A cell in a/an _______ fluid will lose water, and a cell in a/an ________ fluid will gain water.

Background

Topic: Osmosis and Tonicity

This question tests your understanding of how cells respond to different types of extracellular fluids.

Key Terms:

  • Hypertonic solution: Higher solute concentration outside the cell; water moves out.

  • Hypotonic solution: Lower solute concentration outside the cell; water moves in.

Step-by-Step Guidance

  1. Recall the definitions of hypertonic and hypotonic solutions.

  2. Think about the direction water moves in each case (osmosis).

  3. Apply this to the blanks: which type of fluid causes water to leave or enter the cell?

Try to fill in the blanks before checking the answer!

Q5. Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Background

Topic: Fluid Balance and Hormonal Regulation

This question tests your ability to evaluate statements about water loss and hormonal control of fluid balance.

Key Concepts:

  • Sensible water loss: Water loss that is noticeable (e.g., urine, sweat).

  • ADH (antidiuretic hormone): Main hormone regulating water reabsorption in kidneys.

  • Atrial natriuretic peptide (ANP): Hormone that reduces water and sodium reabsorption.

Step-by-Step Guidance

  1. Read each statement carefully and recall the definitions and functions of the terms involved.

  2. Decide if each statement is accurate based on your knowledge.

  3. If a statement is false, think about how you would correct it to make it true.

Try marking each statement before checking the answer!

Q6. Which of the following is false with respect to sodium ions in human physiology?

Background

Topic: Sodium Ion Distribution and Function

This question tests your understanding of the roles and distribution of sodium ions in the body.

Key Concepts:

  • Sodium is the main extracellular cation.

  • Sodium is important for osmotic balance and action potentials.

Step-by-Step Guidance

  1. Review each statement and recall the physiological role and location of sodium ions.

  2. Identify which statement does not accurately describe sodium's role or distribution.

  3. Eliminate the true statements to find the false one.

Try to identify the false statement before checking the answer!

Q7. The biggest source of metabolic acids in the body is:

Background

Topic: Metabolic Acid Production

This question tests your knowledge of the main sources of acid in the body from metabolism.

Key Concepts:

  • Metabolic acids are produced during normal cellular metabolism.

  • Carbon dioxide, lactic acid, ketone bodies, and uric acid are all metabolic byproducts.

Step-by-Step Guidance

  1. Recall which metabolic process produces the most acid in the body.

  2. Consider the relative amounts of each acid produced daily.

  3. Match your reasoning to the answer choices.

Try to select the main source before checking the answer!

Q8. What is the main buffer system of the ECF?

Background

Topic: Buffer Systems

This question tests your understanding of how the body maintains pH in the extracellular fluid (ECF).

Key Terms:

  • Buffer system: A system that minimizes changes in pH by binding or releasing hydrogen ions.

  • Common buffer systems: protein, phosphate, carbonic acid–bicarbonate.

Step-by-Step Guidance

  1. Recall which buffer system is most important in the ECF.

  2. Consider the location and function of each buffer system listed.

  3. Match your reasoning to the answer choices.

Try to identify the main buffer system before checking the answer!

Q9. Explain what happens to the pH of a buffered solution when hydrogen ions are added. Why does this happen?

Background

Topic: Buffer Action

This question tests your understanding of how buffers resist changes in pH.

Key Concepts:

  • Buffers can absorb excess hydrogen ions to minimize pH changes.

Step-by-Step Guidance

  1. Recall the definition and function of a buffer.

  2. Think about what happens when hydrogen ions are added to a buffered solution.

  3. Explain why the pH does not change as much as it would in an unbuffered solution.

Try to explain the effect before checking the answer!

Q10. 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.

Background

Topic: Respiratory Regulation of pH

This question tests your understanding of how breathing affects blood pH and CO2 levels.

Key Concepts:

  • CO2 is converted to carbonic acid in the blood, affecting pH.

  • Ventilation changes CO2 levels, which in turn affects pH.

Step-by-Step Guidance

  1. Recall what happens to CO2 levels when ventilation increases or decreases.

  2. Think about how changes in CO2 affect the concentration of hydrogen ions and thus pH.

  3. Fill in the blanks with the correct terms based on your reasoning.

Try to fill in the blanks before checking the answer!

Q11. Which of the following mechanisms is/are used by the kidneys to regulate the pH of the blood? Circle all that apply.

Background

Topic: Renal Regulation of Acid-Base Balance

This question tests your knowledge of how the kidneys help maintain blood pH.

Key Concepts:

  • The kidneys can secrete or reabsorb hydrogen and bicarbonate ions.

  • Some mechanisms involve the formation of new bicarbonate ions.

Step-by-Step Guidance

  1. Review each mechanism listed and recall how the kidneys regulate acid-base balance.

  2. Identify which mechanisms are involved in pH regulation.

  3. Circle all correct options based on your understanding.

Try to select the mechanisms before checking the answer!

Q12. Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Background

Topic: Acid-Base Disorders and Compensation

This question tests your understanding of respiratory and renal compensation for acid-base imbalances.

Key Concepts:

  • Respiratory acidosis and alkalosis are related to ventilation changes.

  • Renal and respiratory systems compensate for acid-base disturbances at different rates.

Step-by-Step Guidance

  1. Read each statement carefully and recall the mechanisms of compensation.

  2. Decide if each statement is accurate based on your knowledge.

  3. If a statement is false, think about how you would correct it to make it true.

Try marking each statement before checking the answer!

Q13. Your friend argues that all water conducts electricity, regardless of what it contains. You prepare three liquids to test this hypothesis: one with distilled water (with no solutes, only water molecules), one with 5% glucose in distilled water, and one with 5% sodium chloride in water. Which of these solutions, if any, will conduct an electric current? Explain.

Background

Topic: Electrical Conductivity of Solutions

This question tests your understanding of the role of ions in conducting electricity in solutions.

Key Concepts:

  • Only solutions containing ions (electrolytes) conduct electricity.

  • Nonelectrolytes (like glucose) do not dissociate into ions.

Step-by-Step Guidance

  1. Consider the composition of each solution: distilled water, glucose solution, and sodium chloride solution.

  2. Recall which substances dissociate into ions in water.

  3. Determine which solution(s) will conduct electricity based on the presence of ions.

Try to explain your reasoning before checking the answer!

Q14. A woman begins a diet and exercise regimen and loses 30 lb. Will her total body water increase, decrease, or stay the same? Why?

Background

Topic: Body Water and Weight Loss

This question tests your understanding of how changes in body composition affect total body water.

Key Concepts:

  • Fat tissue contains less water than lean tissue.

  • Weight loss can affect total body water depending on what is lost (fat vs. muscle).

Step-by-Step Guidance

  1. Consider what type of tissue is typically lost during weight loss.

  2. Recall the water content of fat versus muscle tissue.

  3. Predict how losing 30 lb would affect total body water.

Try to reason through the effect before checking the answer!

Q15. Explain how the amount of water in the body affects the concentration of ions and solutes in the ECF.

Background

Topic: Water Balance and Osmolarity

This question tests your understanding of how water volume influences solute concentration in the extracellular fluid.

Key Concepts:

  • Osmolarity is the concentration of solutes in a solution.

  • Changes in water volume affect solute concentration.

Step-by-Step Guidance

  1. Recall the definition of osmolarity and how it relates to water and solute amounts.

  2. Think about what happens to solute concentration if water increases or decreases.

  3. Explain the relationship between water volume and solute concentration in the ECF.

Try to explain the relationship before checking the answer!

Q16. 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?

Background

Topic: Respiratory Compensation for Metabolic Acidosis

This question tests your understanding of how the respiratory system compensates for metabolic acidosis.

Key Concepts:

  • Metabolic acidosis lowers blood pH.

  • The body can adjust ventilation to help restore pH balance.

Step-by-Step Guidance

  1. Recall what happens to blood pH in metabolic acidosis.

  2. Think about how the respiratory system can compensate (by changing CO2 levels).

  3. Decide whether hyperventilation or hypoventilation would help correct the acidosis.

  4. Explain how this change in ventilation affects blood CO2 and pH.

Try to reason through the compensation before checking the answer!

Q17. 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.

Background

Topic: Acid-Base Imbalances and Compensation

This question tests your ability to connect clinical symptoms with acid-base disturbances and compensatory mechanisms.

Key Concepts:

  • Vomiting can cause metabolic alkalosis (loss of stomach acid).

  • The body may compensate by altering respiratory rate.

Step-by-Step Guidance

  1. Recall what acid-base disturbance is likely after prolonged vomiting.

  2. Think about how the body compensates for metabolic alkalosis (respiratory changes).

  3. Predict what would happen to arterial blood gas values (pH, CO2, bicarbonate).

Try to connect the symptoms to the acid-base disturbance before checking the answer!

Q18. What happens to the concentration of sodium ions in the ECF if you consume a large amount of salt without consuming any water? How will this affect the osmotic pressure of the ECF? Why could this lead to an elevation in blood pressure?

Background

Topic: Sodium Balance, Osmotic Pressure, and Blood Pressure

This question tests your understanding of how sodium intake affects fluid balance and blood pressure.

Key Concepts:

  • Increased sodium intake raises ECF sodium concentration.

  • Osmotic pressure is determined by solute concentration.

  • Changes in osmotic pressure can affect blood volume and pressure.

Step-by-Step Guidance

  1. Recall what happens to ECF sodium concentration when salt is consumed without water.

  2. Think about how this affects osmotic pressure in the ECF.

  3. Explain how increased osmotic pressure can lead to increased blood volume and blood pressure.

Try to reason through the sequence before checking the answer!

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