ANSWERS

1. What percentage of the body is water?
   60-80%.
2. Is the water content of neonates higher or lower than in adult animals?
   Higher.
3. Describe the distribution of water in the body.
   • Intracellular fluid (ICF) = 66% of the total body water.
   • Extracellular fluid (ECF) = 33% of the total body water.
4. Name the 2 types of extracellular water.
   • Plasma (the fluid part of the blood) = 8% of the ECF.
   • Interstitial fluid (the fluid that bathes the cells of the body outside of the blood vascular system) = 25% of the ECF.
5. By what other name might interstitial fluid be known?
   Tissue fluid.
6. A very small proportion of the body fluid is formed by active secretion such as cerebrospinal fluid (CSF) and gastrointestinal secretions. What is the collective name for these fluids?
   Transcellular fluid.
7. List some functions of the body water.
   • Transport medium.
   • Temperature regulation.
   • Lubrication.
8. Explain the following terms: solution and solvent.
   • Solution = A liquid in which one or more substances have been dissolved.
   • Solvent = A liquid which dissolves or has power to dissolve.
9. What is meant by osmosis?
   The passage of fluid from a low concentration solution to one of a higher concentration through a semi-permeable membrane.
10. What is osmotic pressure?
    The pressure by which water is drawn through a semi-permeable membrane; proportionate to the number of particles in the solution.
11. How is water taken into the body?
    • Drinking.
    • Food.
    • Metabolism.
12. What is meant by "insensible" water losses from the body?
    Losses which cannot be increased or decreased by the body, but depend upon ambient temperatures and the necessity of particular body systems to use water; respiration, perspiration & defecation.
13. What is meant by "sensible" water losses from the body?
    Losses controlled by physiologic functions; urination, lactation & gastrointestinal losses.
14. Explain the following terms: isotonic, hypertonic & hypotonic.
    • Isotonic - a solution that exerts the same osmotic pressure as that of the body fluids.
    • Hypertonic - a solution that exerts a higher osmotic pressure than that of the body fluids.
    • Hypotonic - a solution that exerts a lower osmotic pressure than that of the body fluids.
15. What is an electrolyte?
    Any substance that will split up into ions when dissolved in water; ie. any compound that can conduct an electric current when in solution.
16. What is an ion?
    An atom or group of atoms having an electrical charge by virtue of having gained or lost one or more electrons.
17. What is a cation?
    A positively charged ion.
18. What is an anion?
    A negatively charged ion.
19. What is the main cation and anion of the ECF?
    • Cation - Sodium (Na+).
    • Anion - Chloride (Cl-) 20).
20. What is the main cation and anion of the ICF?
    • Cation - Potassium (K+).
    • Anion - (HC03-).
21. What is the difference between serum and plasma?
    Serum is the clear, fluid residue of blood from which the corpuscles and fibrin have been removed; whilst plasma is the fluid part of the blood in which the corpuscles are suspended.
22. What is pH?
    Per hydrogen; the measure of hydrogen content. pH is measured on a scale of 0-14, with 0 being a very strong acid and 14 being a very strong alkali (or base). A pH of 7 is neutral.
23. What substances are contained within lymph?
    • Water.
    • Gases.
    • Proteins.
    • Non-protein nitrogenous substances.
    • Glucose.
    • Hormones.
    • Enzymes.
    • Vitamins.
    • Immune substances.
24. State the daily water requirement of an adult dog.
    40-60mls/kg/day plus other sensible losses.
25. State the daily water requirement of an adult cat.
    60mls/kg/day.
26. State the daily water requirement of a kitten.
    Up to 150mls/kg/day.
27. What factors may affect the daily water requirements?
    • Pyrexia (fever) - this increases water requirements by 3mls/kg/degrees C increase in body temperature.
    • Water deprivation.
    • Inability to drink.
    • Environmental temperature.
    • Humidity.
    • Metabolic activity.
    • Disease.