NURS3300 Fluids & Electrolytes
Exam Study Set
What does water do? (4) - Answer - Lubricates
- Carries waste and O2 around body
- Regulates temperature
- Aids in food digestion
5 Water Facts - Answer - Primary component of the body
- 50-60% of adult body weight is water
- % of water is > in men
- Fat cells contain < water than lean muscle
- 1 L of water = 2.2 lb = 1 kg
What is average I&O of water? - Answer - 2000-3000 mL
- 1500mL output is urine
- 600-900mL output is insensible loss
- GI secretes ~8000mL digestive fluids that are reabsorbed
Describe simple diffusion - Answer - requires no energy
- movement of molecules from high to low concentration
- movement stops when concentration is = on both sides
Describe facilitated diffusion - Answer - requires no energy
- facilitated by a "carrier" molecule
- movement of molecules from high to low concentration
- movement stops when concentration is = on both sides
Describe active transport - Answer - energy (ATP) is required
- molecules move against concentration gradient
- used when it is necessary to maintain higher or lower levels of molecules on a
particular side of the membrane
,- ex: sodium-potassium pump
Describe osmosis - Answer - movement of water from a less concentrated compartment
to more concentrated compartment
- movement stops when concentration is equal or hydrostatic pressure prevents
movement
Describe hydrostatic pressure - Answer - force within fluid compartment
- hydrostatic pressure = blood pressure
- major force that pushes water out of vessel at capillary level
Describe oncotic pressure - Answer - pressure exerted by colloids in solution
- protein (albumin) major molecule responsible
- attracts water, pulls it from tissues into vascular space
Define isotonic solution - Answer solutions with same osmolality of fluid in the cell
Define hypertonic solution - Answer solutions with > osmolality than interior of cells
(shrink cell, pull water from cell)
Define hypotonic solution - Answer solutions with < osmolality than interior of cells
(expand cell, give for dehydration)
List 3 extracellular compartments - Answer 1. interstitial (between cells)
2. intravascular (in blood vessels)
3. transcellular (specialized areas , ie. pericardial sac)
List 3 theories of fluid spacing - Answer 1st spacing (normal)
2nd spacing (edema, accumulation in interstitial space)
3rd spacing (accumulation in transcellular space)
4 forces that move fluid between capillaries and interstitium - Answer - capillary
hydrostatic pressure
- plasma oncotic pressure
- interstitial hydrostatic pressure
- interstitial oncotic pressure (low)
How does water move out of arterial capillaries? - Answer - capillary hydrostatic
pressure pushes fluid out
, - interstitial oncotic pressure pulls fluid into tissues
How does water move into venous capillaries? - Answer - plasma oncotic pressure pulls
fluids into venous capillaries
- interstitial hydrostatic pressure pushes fluid out of tissues
What contributes to edema? - Answer - any increase in capillary venous hydrostatic
pressure will prevent uptake of fluid (ie fluid overload, HF, liver failure)
- decrease in plasma oncotic pressure (protein low due to malnutrition)
- increase interstitial oncotic pressure (trauma, burns allow proteins to leak out of
capillary walls and into interstitium)
How to correct edema? - Answer 1. Assess & correct underlying problem
2. Give hypertonic IV (pull water out of interstitium)
3. Apply pressure with compression devices (push water back to vessels) Ex. TED hose
Describe hypothalamic regulation - Answer - increase plasma osmolality or FVD is
sensed by osmoreceptors in hypothalamus
- stimulates thirst & release of ADH
- ADH stimulates H2O retention in kidneys by making distal convoluted tubules &
collecting ducts permeable to H2O
- H20 is conserved to correct FVD or decrease plasma osmolality
Describe adrenal cortex regulation - Answer - hypothalamus releases CRH which acts
on anterior pituitary gland
- anterior pituitary releases adrenocortico-tropic hormone which acts on adrenal cortex
- adrenal cortex secretes aldosterone & cortisol
- cortisol enhances Na retention (H2O retention is secondary)
Describe renal regulation - Answer - RAAS system (renin-angiotensin-aldosterone
system)
- helps balance fluid & electrolytes by selectively re-absorbing H2O & electrolytes
Describe cardiac regulation - Answer - hormones produced by cardiomyocytes -
produced in response to increased blood volume in atria and high Na
- suppress RAAS system & lead to Na & H2O excretion in tubules
Describe gastrointestinal regulation - Answer - 8000mL of gastric secretions
reabsorbed daily
Exam Study Set
What does water do? (4) - Answer - Lubricates
- Carries waste and O2 around body
- Regulates temperature
- Aids in food digestion
5 Water Facts - Answer - Primary component of the body
- 50-60% of adult body weight is water
- % of water is > in men
- Fat cells contain < water than lean muscle
- 1 L of water = 2.2 lb = 1 kg
What is average I&O of water? - Answer - 2000-3000 mL
- 1500mL output is urine
- 600-900mL output is insensible loss
- GI secretes ~8000mL digestive fluids that are reabsorbed
Describe simple diffusion - Answer - requires no energy
- movement of molecules from high to low concentration
- movement stops when concentration is = on both sides
Describe facilitated diffusion - Answer - requires no energy
- facilitated by a "carrier" molecule
- movement of molecules from high to low concentration
- movement stops when concentration is = on both sides
Describe active transport - Answer - energy (ATP) is required
- molecules move against concentration gradient
- used when it is necessary to maintain higher or lower levels of molecules on a
particular side of the membrane
,- ex: sodium-potassium pump
Describe osmosis - Answer - movement of water from a less concentrated compartment
to more concentrated compartment
- movement stops when concentration is equal or hydrostatic pressure prevents
movement
Describe hydrostatic pressure - Answer - force within fluid compartment
- hydrostatic pressure = blood pressure
- major force that pushes water out of vessel at capillary level
Describe oncotic pressure - Answer - pressure exerted by colloids in solution
- protein (albumin) major molecule responsible
- attracts water, pulls it from tissues into vascular space
Define isotonic solution - Answer solutions with same osmolality of fluid in the cell
Define hypertonic solution - Answer solutions with > osmolality than interior of cells
(shrink cell, pull water from cell)
Define hypotonic solution - Answer solutions with < osmolality than interior of cells
(expand cell, give for dehydration)
List 3 extracellular compartments - Answer 1. interstitial (between cells)
2. intravascular (in blood vessels)
3. transcellular (specialized areas , ie. pericardial sac)
List 3 theories of fluid spacing - Answer 1st spacing (normal)
2nd spacing (edema, accumulation in interstitial space)
3rd spacing (accumulation in transcellular space)
4 forces that move fluid between capillaries and interstitium - Answer - capillary
hydrostatic pressure
- plasma oncotic pressure
- interstitial hydrostatic pressure
- interstitial oncotic pressure (low)
How does water move out of arterial capillaries? - Answer - capillary hydrostatic
pressure pushes fluid out
, - interstitial oncotic pressure pulls fluid into tissues
How does water move into venous capillaries? - Answer - plasma oncotic pressure pulls
fluids into venous capillaries
- interstitial hydrostatic pressure pushes fluid out of tissues
What contributes to edema? - Answer - any increase in capillary venous hydrostatic
pressure will prevent uptake of fluid (ie fluid overload, HF, liver failure)
- decrease in plasma oncotic pressure (protein low due to malnutrition)
- increase interstitial oncotic pressure (trauma, burns allow proteins to leak out of
capillary walls and into interstitium)
How to correct edema? - Answer 1. Assess & correct underlying problem
2. Give hypertonic IV (pull water out of interstitium)
3. Apply pressure with compression devices (push water back to vessels) Ex. TED hose
Describe hypothalamic regulation - Answer - increase plasma osmolality or FVD is
sensed by osmoreceptors in hypothalamus
- stimulates thirst & release of ADH
- ADH stimulates H2O retention in kidneys by making distal convoluted tubules &
collecting ducts permeable to H2O
- H20 is conserved to correct FVD or decrease plasma osmolality
Describe adrenal cortex regulation - Answer - hypothalamus releases CRH which acts
on anterior pituitary gland
- anterior pituitary releases adrenocortico-tropic hormone which acts on adrenal cortex
- adrenal cortex secretes aldosterone & cortisol
- cortisol enhances Na retention (H2O retention is secondary)
Describe renal regulation - Answer - RAAS system (renin-angiotensin-aldosterone
system)
- helps balance fluid & electrolytes by selectively re-absorbing H2O & electrolytes
Describe cardiac regulation - Answer - hormones produced by cardiomyocytes -
produced in response to increased blood volume in atria and high Na
- suppress RAAS system & lead to Na & H2O excretion in tubules
Describe gastrointestinal regulation - Answer - 8000mL of gastric secretions
reabsorbed daily
