NMNC 3210 EXAM 1- FLUID AND ELECTROLYTES
Osmolality - Answers - measures the number of milliosmoles per weight of water, or
the concentration of molecules per weight of water. Preferred measure to evaluate the
concentration of plasma, urine, and other body fluids ((changes in the ECF osmolality
can significantly influence changes in the ICF osmolality))
Calculating plasma osmolality - Answers - (2xNa) + (BUN/2.8) + (glucose/18)
Tonicity - Answers - the capability of a solution to modify the volume of cells by altering
their water content
insensible water loss - Answers - through the skin and lungs, it can neither be
perceived or measured directly and is estimated to be between 600-800mL per day
without comorbidities, helps regulate body temperatures
hypovolemia (ECF volume deficit) - Answers - occurs with abnormal loss of body
fluids, inadequate fluid intake, or a shift from plasma to interstitial fluid
hypervolemia (ECF volume excess) - Answers - may result from excess intake of
fluids, abnormal retention of fluids, shift of fluid from interstitial fluid into plasma fluid
hypertonic solutions - Answers - solutions with greater solute concentration than in the
cell interior, i. makes water move out of the cell
isotonic solutions - Answers - solutions with the same osmolality as the cell interior
hypotonic solutions - Answers - solutions with less solute concentration than in the cell
interior, makes water move into the cell
main body fluid compartments - Answers - Intracellular fluid (ICF) and Extracellular
fluid (ECF)
Intracellular fluid (ICF) make up - Answers - 2/3 of body water and 40% of body weight
in adult
Extracellular fluid (ECF) make up - Answers - 1/3 of body water and 20% of body
weight in adult
Extracellular fluid (ECF) compartments - Answers - Interstitial fluid 2/3 , Intravascular
fluid 1/3
major electrolytes in the ECF - Answers - Sodium (Na+), Chloride (Cl-), Calcium
(Ca2+)
, major electrolytes in the ICF - Answers - Potassium (K+), Magnesium (Mg2+),
Phosphorus (P-)
Diffusion pressure definition - Answers - the movement of molecules from an area of
high concentration to low concentration
Osmosis pressure definition - Answers - the movement of water down a concentration
gradient from a region of low solute concentration to one of high solute concentration
Active transport definition - Answers - process in which molecules move against the
concentration gradient, using external energy
Hydrostatic pressure definition - Answers - the force of fluid in a compartment pushing
against a cell membrane or vessel wall, moves (pushes) fluid out of capillaries
Oncotic pressure definition - Answers - is the osmotic pressure caused by plasma
colloids in solution, pulling water into the capillary
What is third spacing? - Answers - Occurs when excess fluid collects in the
nonfunctional area between cells, this fluid is trapped where it is difficult or impossible
for it to move back into the cells or blood vessels
How is hypovolemia different from dehydration? - Answers - Dehydration refers to loss
of pure water, causing an increase in sodium and hypovolemia (fluid volume deficit)
refers to loss of water and sodium
Hypovolemia has a risk of circulatory compromise and dehydration has less risk of
circulatory compromise
What are the elements in the normal 24- hour fluid balance in the adult (I and O)? -
Answers - a. Intake (I)= 2500mL
i. Fluids 1200mL
ii. Solid food 1000mL
iii. Water from oxidation 300mL
b. Output (O)= 2500mL
i. Insensible loss (skin and lungs) 900mL
ii. In feces 100mL
iii. Urine 1500mL
Fluid volume deficit (hypovolemia) definition - Answers - decrease in extracellular fluid
generally secondary to combined sodium and water loss
Fluid volume deficit (hypovolemia) potential causes - Answers - abnormal loss of body
fluids (diarrhea, vomiting, hemorrhage, polyuria), inadequate fluid intake, diuretic,
diabetes mellites, AKI, burns, excessive sweating, decreased thirst or a shift from
plasma to intestinal fluid
Osmolality - Answers - measures the number of milliosmoles per weight of water, or
the concentration of molecules per weight of water. Preferred measure to evaluate the
concentration of plasma, urine, and other body fluids ((changes in the ECF osmolality
can significantly influence changes in the ICF osmolality))
Calculating plasma osmolality - Answers - (2xNa) + (BUN/2.8) + (glucose/18)
Tonicity - Answers - the capability of a solution to modify the volume of cells by altering
their water content
insensible water loss - Answers - through the skin and lungs, it can neither be
perceived or measured directly and is estimated to be between 600-800mL per day
without comorbidities, helps regulate body temperatures
hypovolemia (ECF volume deficit) - Answers - occurs with abnormal loss of body
fluids, inadequate fluid intake, or a shift from plasma to interstitial fluid
hypervolemia (ECF volume excess) - Answers - may result from excess intake of
fluids, abnormal retention of fluids, shift of fluid from interstitial fluid into plasma fluid
hypertonic solutions - Answers - solutions with greater solute concentration than in the
cell interior, i. makes water move out of the cell
isotonic solutions - Answers - solutions with the same osmolality as the cell interior
hypotonic solutions - Answers - solutions with less solute concentration than in the cell
interior, makes water move into the cell
main body fluid compartments - Answers - Intracellular fluid (ICF) and Extracellular
fluid (ECF)
Intracellular fluid (ICF) make up - Answers - 2/3 of body water and 40% of body weight
in adult
Extracellular fluid (ECF) make up - Answers - 1/3 of body water and 20% of body
weight in adult
Extracellular fluid (ECF) compartments - Answers - Interstitial fluid 2/3 , Intravascular
fluid 1/3
major electrolytes in the ECF - Answers - Sodium (Na+), Chloride (Cl-), Calcium
(Ca2+)
, major electrolytes in the ICF - Answers - Potassium (K+), Magnesium (Mg2+),
Phosphorus (P-)
Diffusion pressure definition - Answers - the movement of molecules from an area of
high concentration to low concentration
Osmosis pressure definition - Answers - the movement of water down a concentration
gradient from a region of low solute concentration to one of high solute concentration
Active transport definition - Answers - process in which molecules move against the
concentration gradient, using external energy
Hydrostatic pressure definition - Answers - the force of fluid in a compartment pushing
against a cell membrane or vessel wall, moves (pushes) fluid out of capillaries
Oncotic pressure definition - Answers - is the osmotic pressure caused by plasma
colloids in solution, pulling water into the capillary
What is third spacing? - Answers - Occurs when excess fluid collects in the
nonfunctional area between cells, this fluid is trapped where it is difficult or impossible
for it to move back into the cells or blood vessels
How is hypovolemia different from dehydration? - Answers - Dehydration refers to loss
of pure water, causing an increase in sodium and hypovolemia (fluid volume deficit)
refers to loss of water and sodium
Hypovolemia has a risk of circulatory compromise and dehydration has less risk of
circulatory compromise
What are the elements in the normal 24- hour fluid balance in the adult (I and O)? -
Answers - a. Intake (I)= 2500mL
i. Fluids 1200mL
ii. Solid food 1000mL
iii. Water from oxidation 300mL
b. Output (O)= 2500mL
i. Insensible loss (skin and lungs) 900mL
ii. In feces 100mL
iii. Urine 1500mL
Fluid volume deficit (hypovolemia) definition - Answers - decrease in extracellular fluid
generally secondary to combined sodium and water loss
Fluid volume deficit (hypovolemia) potential causes - Answers - abnormal loss of body
fluids (diarrhea, vomiting, hemorrhage, polyuria), inadequate fluid intake, diuretic,
diabetes mellites, AKI, burns, excessive sweating, decreased thirst or a shift from
plasma to intestinal fluid
