Maintenance of the Body
Unit 9: Fluids & Electrolytes
Unit outline
Part 1: Body Fluids and Fluid Compartments
- Body water content
- Fluid compartments
- Intracellular fluid
- Extracellular fluid
- Electrolyte balance
- Roles of electrolytes
Part 2: Acid-Base Balance
- Acids
- Bases
- The concept of pH
- Buffers
- Homeostatic imbalance of acids and bases
- Acid-base balance
- Buffer systems in the body
- Respiratory regulation of acid-base balance
- Renal regulation of acid-base balance
- Disorders of acid-base balance
- Metabolic acidosis: primary bicarbonate deficiency
- Respiratory acidosis: primary carbonic acid/CO2 excess
- Respiratory alkalosis: primary carbonic acid/CO2 deficiency
- Compensation Mechanisms
- Respiratory compensation
- Metabolic compensation
Learning Objectives
At the end of this unit, you should be able to:
I. Define and describe the measurement of pH.
II. Describe the electrolyte composition of the body.
III. Describe the mechanisms for the control of electrolytes in the body.
Learning Objectives and Guiding Questions
At the end of this unit, you should be able to complete all the following tasks, including answering the guiding questions associated with each task.
I. Define and describe the measurement of pH.
II. Describe the electrolyte composition of the body.
III. Describe the mechanisms for the control of electrolytes in the body.
- Describe the difference between compounds that are electrolytes and those that are non-electrolytes.
- Specify four functions of ions in the body.
- Compare and contrast the electrolyte composition of each of the following pairs of body fluid compartments:
- Intracellular fluid and blood plasma
- Intracellular fluid and interstitial fluid
- Blood plasma and interstitial fluid
- Of the three major fluid compartments in the human body (intracellular fluid, blood plasma, and interstitial fluid), which two are most similar to each other? Explain why this grouping is not unexpected.
- Define the following terms: electrolyte, acid, base, buffer.
- Define and clearly distinguish between an electrolyte, an acid, and a base.
- Explain the chemical nature of a buffer solution. Describe the function of such solutions in the human body and explain how they perform that function.
- Describe pH and the pH scale.
- Describe how to use the pH scale to determine hydrogen ion concentration, and how to use it to compare two solutions, by completing the following questions:
- Explain in words how to calculate the difference in hydrogen ion concentration between a solution with a pH of 4 and one with a pH of 9.
- State whether each solution described above is acidic, basic or neutral.
- For each of the following solutions, state (a) whether it is acidic or basic, AND (b) whether it is “more acidic” or “less acidic” than a solution with a pH of 7.3:
- A solution with a pH of 7.2
- A solution with a pH of 6.4
- A solution with a pH of 7.8
- Describe the sources of acids and bases in the body.
- Describe the mec