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85 Cards in this Set
- Front
- Back
- 3rd side (hint)
Why is F/E balance important?
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To maintain health and function in all systems
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What groups of people may have problems in maintaining normal F/E balance?
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1. Unhealthy
2. Immobile 3. Older/Younger 4. Decreased LOC |
O DUI
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What systems are involved in I/O of water and electrolytes
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Renal
Hormonal Neural |
RHN
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What are electrolytes (2 definitions)?
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Ions that are dissolved into body fluids
Are vital to many body functions |
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What are non-electrolytes? Give 3 examples.
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Complex molecules dissolved in body fluid but that remain as a complete molecule.
Glucose, creatinine, urea |
GCU
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What are 4 main uses of water in the body?
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1. universal solvent
2. moisture for reactions 3. regulates body T (sweating) 4. Transports solutes/ carries wastes |
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How much water does an adult have?
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~45L or 60% of adult weight
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What are two distinct fluid compartments?
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ICF
ECF |
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Where is most body fluid?
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ICF has 62% of all
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What is the distribution of body fluid?
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ICF = 62%
ISF = 30% IVF = 8% |
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Where the the stablest portion of body fluid?
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ICF
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What are the components of ECF?
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ISF = b/w cells
IVF = plasma = w/in bl vessels TCF = intraocular, CSF, pleural, peritoneal, synovial... |
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What is first spacing?
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Normal distribution of fluid in ICF and ECF
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What is second spacing?
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abnormal interstitial t/f ECF
eg. edema |
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What is third spacing?
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When fluid becomes trapped in a body part that does not easily exchange fluid with rest of ECF - ascities, burn edema, peritonitis
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What electrolytes are present in higher concentrations in ICF
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K, P, Mg
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What ions are present in higher concentrations in ISF?
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Na
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What is considered to be reserve fluid?
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ISF = it can replace fluid in either the bl vessels or the cells
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What ions are present in IVF?
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Na, Cl,
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Which fluid is the least stable?
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IVF
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Which ion is the major regulator of body fluid volume? Where is it mostly found?
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Na
ECF |
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What is the purpose of plasma protein?
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Keeps fluid in intravascular space - oncotic pressure
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What is the most common plasma protein?
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albumin
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What organs are involved in F/E balance?
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kidney
heart liver adrenals pituitary nervous |
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What affects the F/E balance?
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1. fluid volume
2. distribution of fluids 3. concentration of solutes |
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What is the normal range for Na?
Where is it mainly found? |
135-145mmol/L
ECF |
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What is the normal range for K?
Where is it mainly found? |
3.5-5.0 mmol/L
ICF |
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What is the normal range for Cl?
Where is it mainly found? |
95-105
ECF |
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What is the normal range for Bicarbonate?
Where is it mainly found? |
22-26 (arterial)
EFC |
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What is the normal range for Calcium?
Where is it mainly found? |
4.5-5.5
equal in ECF and ICF |
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What is the normal range for Mg?
Where is it mainly found? |
0.6-1.0
ICF |
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What is the normal range for P?
Where is it mainly found? |
1.0-1.5
ICF |
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What 3 pressures/forces influence fluid movement?
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1. Membrane permeability
2. Oncotic pressure 3. Hydrostatic pressure |
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How are membranes permeable?
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Water passes through easily,
ions and molecules are selective |
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What is oncotic pressure
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AKA Colloid osmotic pressure
pressure exerted by non-diffusible plasma protein |
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What is hydrostatic pressure?
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Pressure exerted by pumping of the heart
- pushing force |
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What 4 processes move F/E across semi-permeable membranes?
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1. osmosis
2. diffusion 3. filtration 4. active transport |
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What 2 processes move solutes?
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1. Diffusion
2. active transport |
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What 2 processes move fluid?
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1. osmosis
2. capillary filtration/reabsorption |
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What is osmosis?
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mvmt of water from lower solute concentration to higher solute concentration across a semi permeable membrane to equalise concentration on both
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What is osmolality?
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AKA - tonicity
Force that pulls water into/out of cell |
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What is diffusion?
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mvmt of solute across a semi-permeable membrane from an area of low concentration to
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Movement of O2/CO2 in lungs is an example of?
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Diffusion
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What is filtration?
What moves with filtration? Where is filtration common? |
Mvmt from higher hydrostatic pressure to lower pressure
Water and solutes capillary beds |
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By what 2 processes do F/E move across capillary walls?
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1. Capillary filtration
2. Capillary reabsorption |
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What is capillary filtration?
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Hydrostatic pressure higher at arterial end of capillary, forces F/E into ISF
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What is capillary reabsorption?
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Hydrostatic pressure lower on venous end of capillary, so F/E move back into capillary
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How does CHF alter fluid balance?
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Higher venous hydrostatic pressure so movement of fluid back into capillaries is reduced, resulting in edema
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What is colloid/oncotic pressure
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colloid refers to albumin
capillaries have albumin, so after capillary filtration it pulls water back due to concentration gradient |
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what is active transport?
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requires energy, moves material against their concentration gradient
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What processes control body fluids (homeostasis)?
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1. hormonal
2. fluid intake 3. fluid output |
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What are 3 hormonal fluid control systems?
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1. RAA
2. Aldosterone 3. ADH |
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What is renin?
When is it released (3)? |
Enzyme secreted by kidney in response to
- low blood volume, - changes in arterial pressure - low sodium in plasma |
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What does renin do?
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Converts angiotensin to AgT1
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Where is AgT1 converted to AgTII?
What does it do (3)? |
In the lungs,
- Powerful vasoconstrictor - regulates release of aldosterone - increases Na reabsorption |
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What is aldosterone?
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hormone secreted by adrenal glands in response to
- low Na, high K in ECF - decreased circulating volume - raised AgTII |
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What does aldosterone do?
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increases Na and water reabsorption and K excretion by kidney
--> increases blood pressure |
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What 5 things cause a relase in aldosterone?
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High K
Low Na Low BV Low CO Low aBP --> all cause decreased renal perfusion |
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What is ADH?
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AKA Vasopressin
- regulates water retention - released by pituitary - high Na - hypotension |
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What does ADH do?
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Increased water reabsorption
--> increased BP |
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How is thirst controlled?
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Hypothalamus stimulated with increased serum osmolality
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When is thirst stimulated (5)?
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When 2% of body weight lost through hypovolemia, RAA, K depletion, psycological, mouth dry
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What would D5NS do to thirst?
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Increase, since it is a hypertonic solution it would increase plasma osmolality
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What organs (4) are involved with fluid output?
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Kidney
Skin Lungs GI |
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How much urine is normally produced per day?
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1200-1500 mL
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What is insensible water loss?
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Through skin and lungs - can't tell it is being lost
Assists temperature control around 900mL/day ONLY WATER (no electrolytes like with sweating) |
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What is sensible water loss?
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Excessive sweating caused by fever or exercise - large WATER and ELECTROLYTE loss
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How much fluid is lost per day from GI?
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100-200 mL
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What is atrial natriuretic peptide?
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ANP released from R atrium when overstretched
Blocks ADH - promotes diuresis Block aldosterone release - promotes Na excretion (and water) Vasodilation |
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What is the primary way in which fluids move between ICF and ECF?
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Osmotic forces
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What is the Starling hypothesis?
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Net filtration = forces favouring filtration - forces opposing filtration
Overall - filtration = arterial end Reabsorption = venous end |
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What forces favour filtration?
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hydrostatic pressure
interstitial oncotic pressure |
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What forces oppose filtration?
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Plasma oncotic pressure
interstitial hydrostatic pressure |
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Water and Cl follow what electrolyte?
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Na
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What is the primary regulator of water balance?
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ADH (Posterior pituitary)
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What is the primary regulator of Na?
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Aldosterone by adrenal cortex, promotes reabsorption in renal tubules
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What are causes of F/E imbalances?
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Illness - CHF, burns
Therapeutic - IV fluids, diuretics |
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What is the effect of hypernatremia at a cellular level?
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Water moves out of cell into ECF - cellular dehydration
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What is the primary protection against hyperosmolality/hypernatremia?
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Hypothalamus development of thirst
- therefore, frail, elderly, LOC down all have inability to obtain fluids |
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What are some clinical conditions that can produce hypernatremia?
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Central diabetes insipidus - ADH decrease
Nephrogenic diabetes insipidus - decrease kidney response to ADH hyperosmolar tube feed osmotic diuretic hyperglycemia (DM) result in dilute urine production excessive sweating |
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What are S&S of hypernatremia?
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intense thirst, lethargy, agitation, seizures, coma
+ volume imbalance |
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What is a cause of hyponatremia?
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loss of Na containing fluid or from excess water loss causing water shift into cells
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What are common causes of water excess?
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add too much water
lose Na - |
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What are symptoms of hyponatremia?
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related to cellular swelling
- irritability, apprehension, confusion, headache, lassitude, apathy, weakness, confusion, muscle spasm, seizures, coma |
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What are the rules of fluid replacement?
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Blood - blood
plasma - colloid (plasma/albumin) resuscitate - colloid ECF with saline Rehydrate with dextrose |
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