AP110 Chp 21 Body fluids

Question 1

Importance of water

Answer 1

• Body fluid maintenance
• Thirst mechanism maintains volume
• Kidney activity regulates volume and composition
• Hormones regulate fluid volume and electrolytes
• Buffers, respiration, and kidney function regulate pH.

Question 2

Fluid components

Answer 2

Intracellular fluid (ICF)
-Two-thirds to three-fourths of all body fluids

Extracellular fluid (ECF)

• Interstitial fluid (15% of body weight)
• Blood plasma (4% of body weight)
• Lymph (1% of body weight)
• Fluid in special compartments (1% to 3% of total body fluids)

Question 3

Water balance

Answer 3

Average adult takes in about 2300 mL of water from
Beverages
Food
Cellular respiration

Water loss from
Kidneys (1 to 1.5 L daily)
Skin 
Lungs
Intestinal tract

Question 4

Sense of thirst

Answer 4

Control center located in the hypothalamus
Regulates total fluid volume
Excessive thirst (polydipsia)

Question 5

Electrolytes and their functions

Answer 5

Conduct electrical current in solution
Positive ions (cations)
Sodium (most abundant ion in interstitial fluid)
Potassium (most abundant ion in intracellular fluid)
Calcium

Negative ions (anions)
Phosphate (most abundant ion in intracellular fluid)
Chloride (most abundant ion in interstitial fluid)
Bicarbonate

Question 6

Electrolyte balance

Answer 6

Kidneys do majority of balancing
Hormones involved
Aldosterone (reabsorb sodium)
Antidiuretic ADH (reabsorbtion of water back into blood)
Parathyroid hormone (reabsorb calcium into blood)
Calcitonin hormone (reabsorb calcium)

Question 7

Regulation of pH

Answer 7

Buffer systems accept or release ions as needed.
Bicarbonate
Phosphate
Proteins

Respiration provides short term regulation

Kidney function provides long term regulation

Question 8

Abnormal pH

Answer 8

Acidosis

• pH less than 7.35
• Depressed nervous system

Alkalosis

• pH greater than 7.45
• Excited nervous system

Origins

• Respiratory - change in blood CO2
• Metabolic - change in other acids

Question 9

Disorders of body fluids

Answer 9

Edema (excess interstitial fluid in the tissues)
Water intoxication (dilution of body fluids in both intracellular and extracellular compartments, swelling may lead to convulsions, coma and finally death)
Ascites (accumulation of fluid within the abdominal cavity)
Dehydration (sever deficit of body fluids, will result in death if it is prolonged.)

Question 10

Fluid therapy

Answer 10

Fluids administered
Normal saline (0.9%)
5% dextrose in 0.45% saline
5% dextrose in water
Ringer lactate solution
Serum albumin 25%
Nutritional solutions