Fluid, Electrolyte, And Acid-Base Balance

Question 1

Indicate the relative fluid volume and solute composition of the fluid compartments of the body

Answer 1

Intercellular compartment contains slightly less than two/thirds by volume

Remaining third is distributed in extra cellular fluid (blood plasma and interstitial fluid)

Question 2

Contrast the overall osmotic effects of electrolytes and non-electrolytes

Answer 2

Electrolytes dissociate in water to ions, include inorganic salts, acids, bases, and some proteins

Electrolytes have greater osmotic pressure power

Electrolytes are most abundant solutes on bodily fluids

Nonelectrolytes include most organic molecules, dont dissociate in water, carry no electrical charge

Question 3

What is the major cation extracellular fluid? Intracellular?

Answer 3

Extracellular - sodium

Intracellular - Potassium

Question 4

Major anion in extracellular fluid? Intracellular?

Answer 4

Extracellular - chloride

Intracellular - phosphate

Question 5

Describe factors that determine fluid shifts in the body.

Answer 5

• Anything that changes solute concentration and leads to net water flows
• Nearly protein free plasma is forced out of the blood by hydrostatic pressure and almost completely reabsorbed
• Movement of water between the interstitial fluid and intracellular fluid involves two way osmotic flow that is equal in both directions

Question 6

List the routes by which water enters and leaves the body.

Answer 6

• Water intake = water output
• Enters by drinking
• Produced by cellular metabolism

Water output from sweat, defacation, urine

Question 7

List feedback mechanisms that regulate water intake and hormonal controls of water output in urine.

Answer 7

Feedback:
- Thirst triggered by decrease in plasma osmolarity (Dry mouth)

Hormonal:

• Amount of water reabsorbed in the renal collecting ducts is proportional to ADH release
• When ADH is low most water in the collecting ducts is NOT reabsorbed
• When ADH is high filtered water is reabsorbed resulting in low irons volume

Question 8

Describe the importance of ionic sodium in fluid and electrolyte balance in the body due to its abundance and osmotic pressure

Answer 8

Because all body fluids are in chemical equilibrium, any change in sodium levels causes a compensatory shift in water affecting plasma volume, blood pressure, and intracellular and interstitial fluid volumes