Body Fluids Flashcards
What fluid compartment has the largest fluid volume
Intracellular fluid (28.0 L)
Interstitial fluid volume
11.0L
Fluid volume in plasma
3.0 L
Intracellular fluid volume
28.0L
Total volume of extracellular fluid
14.0 L 3 L (plasma)+11 L (Interstitial fluid)
Methods for fluid output
kidneys, lungs, feces, Sweat, and Skin
What is Osmolarity
-mOsm (milliosmoles)/L= Concentration of particles per liter of solution
What is Osmolality
- mOsm/kg= concentration of particles per kg solvent
List cation and anion concentration in the extracellular space in decreasing order
NA+>Cl->Bicarbonate>Proteins>Potassium>Calcium
List anion and cation Intracellular concentration in decreasing order
Potassium>Phosphate> Proteins>Magnesium> Sodium> Bicarbonate> Chloride
Effective osmole
Refers to a solute that does not easily cross a membrane. It is an effective osmole because it creates an osmotic forces for water.
what are effective osmoles for the vascular compartment
Proteins
What is the most prominent non electrolyte of plasma
Phospholipids (280mg/dl)
List the non-electrolyte composition of plasma in decreasing order
Phospholipids>Cholesterol>Neutral fat>Glucose>Urea>Lactic Acid>Uric Acid>creatinine> Billirubin>Bile salts
Daily ingested water intake is how much
2100 ml/day
Daily intake of water via metabolism is how much
200 ml/day
What is the total daily intake of water
2300 ml/day
What is the total daily volume of water loss
2300 ml/day
What is the daily volume of water lost by insensible evaporation
350 ml/day through skin (3-5 liters/day for severe burns)
350ml/day via the lungs
What is the daily volume of water lost from sweatign
100 mL/day (5000 mL/day during exercise)
What is the volume of water lost through feces
100mL/day
What is the total volume of water lost through Urine
1400 mL/day (500 mL/day during exercise)
The intracellular compartments hold what percent of fluid content
40%
What is the total volume of water in the body in a 70kg male
42 liters
What percent of female body weight is water
50%
What percent of premature and newborn’s body weight is water
70-75%
What are the components of a BMP
Sodium, potassium, Chloride, bicarbonate, BUN, Creatnine , and Glucose
What are the normal BMP
Sodium-140 Potassium- 4 Chloride- 104 bicarbonate- 24 BUN- 15 mg/dl Creatnine- 1 mg/dl Glucose- 80 mg/dl
What is an osmolar gap
- difference between the measured osmolality and the estimated osmolatity (normal greater than or equal to 15)
- ECF effective osmolality=2(Na+) mEq/L + (glucose mg%/18)+ (urea mg%/2.8)
What are 5 common things that can elevate osmolar gap
Ethanol, Methanol, Ethylene glycol, Acetone, Mannitol
Why is the ionic composition of plasma and interstitial fluid so similar
-because they are separated by highly permeable capillary membranes
Why is their a higher concentration of proteins in plasma
because capillaries have a low permeability to plasma proteins
Intracellular fluid composition
- Small amounts of sodium and Chloride ions
- almost no calcium ions
- large amounts of potassium and phosphate ions
- Moderate amounts of magnesium and sulphate ions
The indicator-dilution principle applies to measurement of
fluid volumes in body fluid compartments
What are the requirements for indicator-dilution principle
-Disperses evenly throughout compartment
- Disperses only in compartment being measured
- Not metabolized or excreted
- Not toxic
(volume B)= Volume A x concentration A/ concentration B
Relative amounts of extracellular fluids in interstitial spaces and plasma are determined primarily by
balance of hydrostatic and colloid forces across capillary membranes
Distribution of fluid between intracellular and extracellular compartments is determined mostly by
osmotic effects primarily of sodium and chloride ions
The units of concentration in body fluids are typically expressed in terms of
milliosmoles (mOsm)
For each mOsm concentration gradient of an impermeant solute, about _____ Hg osmotic pressure is exerted across the membrane
19.3 mm Hg
The total number of particles in a solution is measured in
osmoles
What is Osmolality
When the concentration is expressed as osmoles/Kg water
What is Osmolarity
When the concentration is expressed as osmoles/liter
about 80% of total osmolarity of the interstitial fluid and plasma is due to
sodium and chloride
For intracellular fluid, about half of the osmolarity is due to
potassium ions
if the cell membrane is exposed to pure water and the osmolarity of intracellular fluid is 282 mOsm/L The potential osmotic pressure that can develop across the cell membrane
is more than 5400 mm Hg
Addition of isotonic saline to extracellular fluid compartment has what effect on extracellular osmolarity and volume
- osmolarity does not change
- volume increases
A solution of impermeant solutes having an osmolarity of 282 mOsm/L is
isotonic
What are some examples of an isotonic solution
0.9% NaCl or 5% Glucose
in an isotonic solution water
cannot enter or leave the cell
Addition of hypertonic saline to extracellular fluid compartment has what effect on intracellular and extraceullar volume and osmolarity
Intracellular volume decreases
Extracellular volume increases
Osmolarity in both compartments increases
A solution of impermeant solutes having an osmolarity > 282 mOsm/L is
hypertonic
Addition of a hypotonic saline to extracellular fluid compartment has what effect on osmolarity and volume of the extracellular and intracellular compartement
Volume of both compartments increases
Osmolarity in both compartments decreases
A solution of impermeant solutes having an osmolarity
Hypertonic
No matter if the fluid is isotonic, hypotonic, or hypertonic, the extracellular fluid
always has a net gain of fluid and the volume always enlarges
The safety factor against edema is
-3 mm Hg
When interstitial fluid pressure is below 0, does fluid accumulate in the tissues
only a little fluid accumulates in the tissues
When interstitial fluid pressure rises above 0, what happens to free fluid
it accumulates in the tissues
What are the causes of hyponatremia
decreased plasma sodium concentration can result form loss of sodium chloride from the extracellular fluid or addition of excess water to the extracellular fluid.
Can be caused by diarrhea and vomiting, overuse of diuretics , and Addison’s disease (which results from decreased secretion of the hormone aldosterone, and impairs the ability of the kidneys to reabsorb sodium and can cause a modest degree of hyponatremia
Hyponatremia-dehydration- causes and effects on plasma sodium concentration as well as intracellular and extracellular fluid volume
Cause- adrenal insufficiency, overuse of diuretics
effects: Plasma Na+ concentration-decreases, Extracellular fluid volume decreases, Intracellular fluid volume Increases
Hyponatremia-overhydration- causes and effects on plasma sodium concentration as well as intracellular and extracellular fluid volume
Causes: Excess ADH, Bronchogenic tumors
Effects: Plasma Na+ concentration decreases, Extracellular Fluid Volume Increases, Intracellular fluid volume Increases
Hypernatremia-dehydration causes and effects on plasma sodium concentration as well as intracellular and extracellular fluid volume
causes: Diabetes insipidus, excessive sweating
Effects: Plasma Na+ concentration increases, Extracellular fluid volume decreases, Intracellular fluid volume decreases
Hypernatremia-Overhydration- causes and effects on plasma sodium concentration as well as intracellular and extracellular fluid volume
Causes: Cushing’s syndrome, primary aldosteronism
Effects: Plasma Na+ concentration increases, Extracellular fluid volume increases, Intracellular fluid volume decreases
A rapid reduction in plasma sodium concentrations can have what effect on the brain
Brain cell edema and neurological symptoms, including headache, nausea, lethargy, and disorientation.
IF plasma sodium concentration rapidly falls below ___ to ___ mmol/L, brain swelling may lead to seizures, coma, permanent brain damage, and death.
115-120 mmol/L
The brain cannot increase its volume by more than about ____ percent without being forced down the neck (herniation),, which can lead to permanent brain injury and death
10 percent
What is the most common electrolyte disorder encountered in clinical practice and may occur in up to 15% to 25% of hospitalized patients
Hyponatremia
The osmotic-mediated demylination of neurons associated with correcting hyponatremia to quickly can be avoided by
limiting the correction of chronic hyponatremia to less than 10-12 mmol/L in 24 hours and to less than 18 mmol/L in 48 hours
What are the causes of Hypernatremia
Increase in loss of water form extracellular fluid or excess sodium in extracellular fluid
Primary loss of water: hypernatremia and dehydration may be due to lack/inability to secrete ADH, which leads to an increase in water excreted as urine (diabetes insipidus)
Gain of sodium- Hypernatremia– overhydration- increase secretion of aldosterone leads to increase Na+ (not it also leads to ADH release and thus large increase in water reabsorption)
How to correct for hyponatremia
Administering hypo-osmotic sodium chloride or dextrose solutions.
3 major causes of intracellular edema
hyponatremia, depresssion of metabolic systems of the tissues, lack of adequate nutrition to the cells.
Two major general causes of extracellular edema
abnormal leakage of fluid from the plasma to the interstitial spaces across the capillaries, failure of the lymphatics to return fluid from the interstitium back into the blood (lymphedema).
What is the most common clinical causes of interstitial fluid accumulation
excessive capillary fluid filtration
What three factors can increase capillary filtration rate
Increased capillary filtration coefficient
Increased capillary hydrostatic pressure
Decreased plasma colloid osmotic pressure
Conditions that cause extracellular edema by increased capillary pressure
A.) Excessive kidney retention of salt and water (acute/chronic renal failure, mineralocorticoid excess)
B.) High venous pressure and venous constriction
(heart failure, Venous obstruction, Failure of venous pumps) ( Paralysis of muscles, Immobilization of parts of the body, failure of venous valves)
C.) Decreased arteriolar resistance
(Excessive body heat, insufficieny of sympathetic nervous system, Vasodilator drugs)
Conditions that cause extracellular edema by decreased plasma proteins
A.) Loss of proteins in urine (nephrotic sysndrome)
B.) Loss of proteins from denuded skin areas
(burns, wounds)
C.) Failure to produce proteins (liver disease, serious protein or caloric malnutrition)
Conditions that cause extracellular edema by Increased capillary permeability
A.) immune reactions that cause release of histamine and other immune products
B.) Toxins
C.) Bacterial Infections
D.) Vitamin deficiency, especially Vitamin C
E.) Prolonged ischemia
F.) Burns
Conditions that cause extracellular edema by blockage of lymph return
A.) Cancer
B.) Infections (ex. Filaria nematodes)
C.) Surgery
D.) Congenital absence or abnormality of lymphatic vessels
What are the 3 safety factors that prevent excessive edema
low compliance of the interstitium when interstitial fluid pressure is in the negative pressure range,
The ability of lymph flow to increase 10-to-50fold,
“washdown” of interstitial fluid protein concentration, which reduces interstitial fluid colloid osmotic pressure as capillary filtration increases
What is the safety factor caused by increased lymph flow that prevents interstitial edema
7mm Hg
What is the total safety factor (include the three individual factors) against edema
about 17 mmHg
What is the range for pitting edema
intersitial free fluid pressure of +2 to +4
Interstitial fluid volume (44 Liters)
