1. Fluid and Electrolyte Balance

2. Fluid and Electrolyte Balance
Water is most abundant compound in body;
60% of body weight in males;
50% in females,
80% in infants,
Volume averages 40 L in a 70-kg male

3. Fluid and Electrolyte Balance
Variation in total body water is related to:
Total body weight,
Fat content of the body,
Gender,
Age.
Fat content of body—the more fat the less water (adipose tissue is low in water content)
Gender—female body has about 10% less water than male body
Age-high in childhood of total body weight. In older adults, water per pound of weight decreases (muscle tissue—high in water—replaced by fat, which is lower in water)

4. Fluid and Electrolyte Balance
Functions of Water in the Body
Transporting nutrients to cells and wastes from cells,
Transporting hormones, enzymes, blood platelets, and red and white blood cells,
Facilitating cellular metabolism and proper cellular chemical functioning,
Acting as a solvent for electrolytes and nonelectrolytes,
Helping maintain normal body temperature,
Facilitating digestion and promoting elimination,
Acting as a tissue lubricant

5. Fluid and Electrolyte Balance
Total body fluid:
Intracellular Fluid (ICF) appx. 25L
Extracellular Fluid
Plasma: 3L
Interstitial and Transcellular Fluid: 12L
Intracellular fluid (ICF)
Largest fluid compartment
Located inside cells
Serves as solvent to facilitate intracellular chemical reactions
Extracellular fluid (ECF)
Plasma
Interstitial fluid (IF)
Transcellular fluid—lymph; joint fluids; cerebrospinal fluid; eye humors
Called internal environment of body
Surrounds cells and transports substances to and from them

6. Fluid and Electrolyte Balance

7. Fluid and Electrolyte Balance

8. Fluid and Electrolyte Balance
Osmosis – Fluid passes from areas of low solute concentration to areas of high solute concentration
Diffusion – tendency of solutes to move freely from areas of high concentration to low concentration
Active Transport – requires energy to move through a cell membrane from area of lesser concentration to greater concentration
Filtration – passage of fluid through a permeable membrane. Movement is from high to low pressure

9. Fluid and Electrolyte Balance
Osmolarity (concentration) of a solution:
Isotonic — same concentration of particles as plasma
Hypertonic — greater concentration of particles than plasma
Hypotonic — lesser concentration of particles than plasma

10. Fluid and Electrolyte Balance
No fluid movement
ISOTONIC
Fluid movement into veins
HYPERTONIC
Fluid movement out of veins
HYPOTONIC

11. Fluid and Electrolyte Balance
Osmosis: Movement of water through a
semipermeable membrane
Diffusion: Movement of particles from high
concentration to lower concentration
Filtration
Active transport

12. Fluid and Electrolyte Balance
Osmosis:

13. Fluid and Electrolyte Balance
Diffusion:

14. Fluid and Electrolyte Balance
Filtration:

15. Fluid and Electrolyte Balance
Active Transport: (Requires energy to transfer)

16. Fluid and Electrolyte Balance Mechanism
Fluid output, mainly urine volume, adjusts to fluid intake; antidiuretic hormone (ADH) from posterior pituitary gland acts to increase kidney tubule reabsorption of sodium and water from tubular urine into blood, thereby tending to increase ECF (and total body fluid) by decreasing urine volume

17. Fluid and Electrolyte Balance Mechanism cont’d
ECF electrolyte concentration (mainly Na+ concentration) influences ECF volume; an increase in ECF Na+ tends to increase ECF volume by increasing movement of water out of ICF and by increasing ADH secretion, which decreases urine volume, and this, in turn, increases ECF volume

18. Fluid and Electrolyte Balance Mechanism cont’d

19. Fluid and Electrolyte Balance Mechanism cont’d
Two main factors regulate the Plasma/Interstitial Fluid (IF) volume:
Capillary blood pressure pushes water out of plasma into IF,
High protein concentration in plasma pulls water from IF into plasma

20. Fluid and Electrolyte Balance
Electrolytes
Positively charged ions (e.g., potassium [K+] and sodium [Na+])
Negatively charged ions (e.g., chloride [Cl] and bicarbonate [HCO3 ]
Nonelectrolytes—organic substances that do not break up or dissociate when placed in water solution (e.g., glucose)
Electrolytes—compounds that break up or dissociate in water solution into separate particles called ions (e.g., sodium chloride)
Ions—the dissociated particles of an electrolyte that carry an electrical charge (e.g., sodium ion [Na+])
Positively charged ions (e.g., potassium [K+] and sodium [Na+], Magnesium Mg++)
Negatively charged particles (ions) (e.g., chloride [Cl] and bicarbonate [HCO3], and phosphate [HPO¯¯4]

21. Fluid and Electrolyte Balance
Electrolyte composition of blood plasma
Sodium—most important positively charged ion of plasma
Normal plasma level—142 mEq/L
Chief method of regulation—kidney
Aldosterone increases Na+ reabsorption in kidney tubules
SHOULD KNOW THE NORMAL LEVELS OF ALL PLASMA IONS:
NA, K, Mg, Cl, HCO, HPO

22. Functions of electrolytes and their normal ranges
Positive Ions
(Cations)
Functions in the body
Normal adult range*
Calcium (Ca++)
Necessary for muscle contraction, nerve function, blood clotting, cell division, healthy bones and teeth
mEq/L
Potassium (K+)
Regulates heart contraction, helps maintain fluid balance
mEq/L
Magnesium (Mg++)
Necessary for muscle contraction, nerve function, heart rhythm, bone strength, generating energy and building protein
mEq/L
Sodium (Na++)
Maintains fluid balance and necessary for muscle contraction and nerve function
mEq/L

23. Functions of electrolytes and their normal ranges
Negative Ions
(Anions)
Functions in the body
Normal adult range*
Bicarbonate (HCO3-)
Essential for acid base balance
22-26 mEq/L
Chloride (Cl-)
Maintains fluid balance, Regulates acid-base balance
mEq/L
Phosphate (PO4-)
Acid-base balance, cell division and transmission of heredity, nerve and muscle action
mEq/L

24. Fluid and Electrolyte Imbalance
Dehydration—total volume of body fluids less than normal; fluid output exceeds intake for an extended period
IF treatment is not given, ICF volume and plasma volume decrease; dehydration occurs
Causes:
Diarrhea, vomiting, fever, or taking diuretics
Extended heat exposure,
Excessive sweating, burns
Decreased fluid intake (physical/psychological)
Age
Dehydration—IF treatment is not given, ICF volume and plasma volume decrease; dehydration occurs when fluid output exceeds intake for an extended period

25. Fluid and Electrolyte Imbalance
Overhydration—total volume of body fluids greater than normal; occurs when fluid intake exceeds output;
Causes:
Rapid or excessive IV infusions,
Some kidney/heart diseases,
Intentional excessive intake,
Psychological disorders
Over hydration—total volume of body fluids greater than normal; occurs when fluid intake exceeds output; various factors may cause this (e.g., giving excessive amounts of intravenous fluids or giving them too rapidly may increase intake above output)

26. Electrolyte Imbalance
If the body's electrolytes are not in balance;
Seizures,
Irregular heartbeats,
Muscle weakness or cramps,
Confusion/lethargy,
BP changes may occur.

27. Electrolyte Imbalance
Electrolyte imbalances can be caused by a variety of health conditions, such as;
Chronic heart or kidney disease,
Endocrine diseases (adrenal, pituitary, thyroid, or parathyroid glands),
Eating disorders,
Bone disorders.