Fluid and Electrolytes

• What are the two main compartments of body fluids?

  Intracellular fluid (ICF) and extracellular fluid (ECF)
• What is the difference between intracellular fluid (ICF) and extracellular fluid (ECF)?

  ICF is the fluid inside cells, while ECF is the fluid outside the cells.
• What are the two components of extracellular fluid (ECF)?

  Plasma and interstitial fluid
• What is plasma in the context of body fluids?

  Plasma is the fluid component of blood.
• What is interstitial fluid?

  Interstitial fluid is the fluid between cells.
• How do cell membranes affect the composition of body fluid compartments?

  Cell membranes separate the compartments and maintain distinct compositions of electrolytes.
• What proportion of total body water is found in the intracellular fluid (ICF)?

  Approximately ⅔ of total body water
• What proportion of total body water is found in the extracellular fluid (ECF)?

  Approximately ⅓ of total body water
• What percentage of total body weight is water?

  Approximately 60%
• What is the relationship between intracellular fluid and cellular processes?

  Intracellular fluid plays a crucial role in cellular processes.
• What happens to intracellular fluid (ICF) volume when extracellular fluid (ECF) osmolality increases?

  ICF volume decreases as water moves to the ECF.
• What principle explains the movement of water between ICF and ECF?

  The principle of osmosis explains the movement of water.
• How does water move in relation to solute concentration?

  Water moves towards a higher solute concentration across a semi-permeable membrane.
• How do you estimate total body water (TBW) given body weight and body fat percentage?

  Multiply the lean body mass by a factor of approximately 0.73.
• What is the formula for calculating lean body mass?

  Lean body mass = total body weight x (1 - body fat percentage)
• If a person weighs 70 kg and has a body fat percentage of 20%, what is their lean body mass?

  56 kg
• How do you calculate total body water (TBW) if the lean body mass is 56 kg?

  TBW = 56 kg x 0.73 = 40.88 kg
• How do you calculate extracellular fluid (ECF) volume from lean body mass?

  ECF Volume = lean body mass x 0.2
• If the lean body mass is 56 kg, what is the extracellular fluid volume?

  11.2 liters
• How do you calculate intracellular fluid (ICF) volume from total body water?

  ICF = total body water x (⅔)
• If total body water is 33.6 kg, what is the intracellular fluid volume?

  22.4 kg
• How do you calculate blood volume from lean body mass?

  Blood volume = lean body mass x 70 ml/kg
• If the lean body mass is 56 kg, what is the blood volume?

  3920 ml
• What is the normal ECF osmolarity?

  About 290 mOsm/L
• What are the major differences in electrolyte concentrations between intracellular fluid and extracellular fluid?

  ICF has higher concentrations of K+ and proteins, while ECF has higher concentrations of Na+ and Cl-.
• What happens to cells when extracellular fluid osmolality increases?

  Cells shrink as water moves from the intracellular compartment to the extracellular compartment.
• What happens to cells when extracellular fluid osmolality decreases?

  Cells swell as water moves into the intracellular compartment.
• How does water move in relation to solute concentration during osmosis?

  Water moves from a region of lower solute concentration to a region of higher solute concentration.
• What is a hypertonic solution?

  A hypertonic solution has a higher osmolality than the reference solution.
• What is an isotonic solution?

  An isotonic solution has the same osmolality as the reference solution.
• What is a hypotonic solution?

  A hypotonic solution has a lower osmolality than the reference solution.
• How is tonicity determined?

  Tonicity is determined by comparing the concentration of solutes in the fluid to the reference solution.
• What are the major routes for water intake?

  Drinking fluids, consuming food containing water, and metabolic water.
• What is the primary source of water intake?

  Drinking fluids.
• What types of fluids contribute to water intake?

  Plain water, beverages like juice, tea, and soups.
• How does food contribute to water intake?

  Water content in food like fruits and vegetables contributes significantly.
• What is metabolic water?

  Metabolic water is water produced during cellular metabolism.
• What are the primary routes for water loss?

  Urine, sweat, respiration, and feces.
• What is the major route of water excretion?

  Urine.
• How does sweat contribute to water loss?

  Sweat causes evaporative water loss through the skin, increasing with physical activity and high temperatures.