01 Body Fluids Flashcards Preview

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Flashcards in 01 Body Fluids Deck (17)
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1
Q

Water constitutes approximately how much of total body weight?

A

50-60%

Average young adult male: 60%
Average young adult female: 50% (higher adipose tissue)

2
Q

Highest percentage of TBW (Total body water) is found in what group?

A

Newborns (80% TBW)

This decreases to approximately 65% by 1 year of age and thereafter remains fairly constant.

3
Q

Total Body Water (TBW) is relatively constant for an individual. It is primarily a reflection of?

A

Body fat. Estimates of percentage for TBW should be adjusted downward by approximately 10-20% for obese individuals, and upward by 10% for malnourished individuals.

4
Q

What are the functional fluid compartments of Total Body Water?

A

Extracellular Water: 20% of body weight (1/3 of TBW)

  • 5% Plasma
  • 15% Interstitial Fluid

Intracellular Water: 40% of body weight (2/3 of TBW)
- Largest proportion in skeletal muscle mass

5
Q

Normal chemical composition of the ECF?

A

Na+ (Sodium): Principal Cation

Cl- (Chloride) and HCO3- (Bicarbonate): Principal Anions

6
Q

Normal composition of the ICF?

A

K+ (Potassium) and Mg+2 (Magnesium): Principal Cations
PO4^3- (Phosphate) SO4^-3 (Sulfate): Principal Anions
Proteins

7
Q

How are sodium-containing fluids distributed in the ECF?

A

The administration of sodium-containing fluids expands the interstitial space by approximately three times as much as the plasma.

(For 1L of PNSS, 250mL will go to the intravascular space; 750mL will go to the interstitial space.)

8
Q

How do you calculate for serum osmolality?

A

Calculated serum osmolality = 2Na + (glucose/18) + (BUN/2.8)

9
Q

Normal serum osmolality?

A

The osmolality of intracellular and extra cellular fluids is maintained between 290 and 310 mOsm in each compartment.

10
Q

Highest percentage of TBW (Total body water) is found in what group?

A

Newborns (80% TBW)

This decreases to approximately 65% by 1 year of age and thereafter remains fairly constant.

11
Q

Total Body Water (TBW) is relatively constant for an individual. It is primarily a reflection of?

A

Body fat. Estimates of percentage for TBW should be adjusted downward by approximately 10-20% for obese individuals, and upward by 10% for malnourished individuals.

12
Q

What are the functional fluid compartments of Total Body Water?

A

Extracellular Water: 20% of body weight (1/3 of TBW)

  • 5% Plasma
  • 15% Interstitial Fluid

Intracellular Water: 40% of body weight (2/3 of TBW)
- Largest proportion in skeletal muscle mass

13
Q

Normal chemical composition of the ECF?

A

Na+ (Sodium): Principal Cation

Cl- (Chloride) and HCO3- (Bicarbonate): Principal Anions

14
Q

Normal composition of the ICF?

A

K+ (Potassium) and Mg+2 (Magnesium): Principal Cations
PO4^3- (Phosphate) SO4^-3 (Sulfate): Principal Anions
Proteins

15
Q

How are sodium-containing fluids distributed in the ECF?

A

The administration of sodium-containing fluids expands the interstitial space by approximately three times as much as the plasma.

(For 1L of PNSS, 250mL will go to the intravascular space; 750mL will go to the interstitial space.)

16
Q

How do you calculate for serum osmolality?

A

Calculated serum osmolality = 2Na + (glucose/18) + (BUN/2.8)

17
Q

Normal serum osmolality?

A

The osmolality of intracellular and extra cellular fluids is maintained between 290 and 310 mOsm in each compartment.