2. F&E Flashcards
(42 cards)
Factors that influence body fluid
Age – increase risk with age (skeletal muscle mass decreases as adipose tissue increases), after age 60 water content drops to 45% when 60% in huge healthy adult, infant or small child is also at risk
Gender - Men have more body fluid
Body fat – if pt obese then have less body water because fat cells contain little water
fluid compartments
Intracellular space and Extracellular space (Intravascular space, Interstitial space, Transcellular space)
Intracellular space –
fluid in the cells; 2/3 of body fluid
Extracellular space –
fluid outside the cells 1/3 of body fluid
Intravascular space –
fluid within the blood vessel; contains plasma; approx 3 L of the average 6 L blood volume is plasma (plasma – liquid portion of blood, 20%)
Interstitial space –
contains fluid that surrounds the cell and totals ~ 11-12 L in adult (Lymph is an example of Interstitial fluid) 80%
Transcellular space –
smallest division of the ECF compartment; contains ~ 1L of fluid at any given time (examples: cerbrospinal, pericardial, synovial, intraocular, and pleural fluids; sweat, and digestive secretions)
When a (hypotonic) solution is placed next to (hypertonic) solution, fluid shifts from
the hypotonic (less concentration) solution into a more concentrated (hypertonic) compartment to equalize the concentration
diffusion
solutes move from high concentration to low concentration, This requires no energy – natural tendency, Ex. Exchange of O2 and CO2 in the lung
osmosis
movement of water to dilute volume
Normal movement of fluids through the capillary wall into tissues depends on
Hydrostatic pressure (the pressure exerted by the fluid on the walls of the blood vessel) at both the arterial and the venous ends of the vessel and the osmotic pressure exerted by the protein of the plasma. The direction of fluid movement depends on the differences in these two opposing forces (hydrostatic versus osmotic pressure).
filtration
hydrostatic pressure in the capillaries tends to filter fluid out of the intravascular compartment into the interstitial fluid. Movement of water and solutes occurs from an area of high hydrostatic pressure to an area of low hydrostatic pressure. higher pressure on arterial side – hydrostatic pressure (produced by contracting of heart) – pushes fluid out into capillary beds Other side (venus side) onconic pressure pulls fluid back in, helped by albumin, exert pressure in plasma, draws in the waste and prevents water from being trapped
Sodium-Potassium Pump
active transport, so needs energy to help regulate
Sodium higher concentration outside cell
Potassium higher concentration inside cell
Larger molecules
ADH
(Antidiuretic Hormone) – release hormone from hypothalamus; when water levels low, released then increase reabsorption of water; stops excretion of excess water, when this occurs has increase urine concentration, increases blood volume (so retains water in the body and to constrict blood vessels)
RAAS
(Renin-Angiotension-Aldosterone System) – purpose absorption of salt, water follows salt so increasing fluid volume
adolesterone
reabsorbs salt and water follows salt
ANP
(Atrial Natriuretic Peptide) – senses fluid volume, if increased the releases for diaphoresis of water; inhibits ADH, so increased urinary output of water; right atrium; direct opposite of RAAS; watch urinary output because of potential UTI; in diabetes insipidus – higher diuretic effect
serum samples drawn from
when reading lab results, these are serum samples which is drawn from the extra cellular space, more specifically intravascular space (differs from Interacellular space) therefore it is telling you how much of the solute is outside of the cell
osmolarity
reflects the concentration of fluid that affects the movement of water between fluid compartments by osmosis; Measures the solute concentration per kilogram in blood and urine
urine specific gravity
how concentrated the urine is, the higher the urine specific gravity the higher the concentration, measures the kidney’s ability to excrete or conserve water, Urine normal range = 1.010 – 1.025
three processes involved in balancing electrolytes
- Distribution
- Intake and absorption )
- Output
Isotonic solutions
NS, D5W, Ringers Lactate (LR)
The solute concentration is about equal to that of serum. Therefore, it stays in the intravascular space after administration.
Same osmolality as intravascular space (so no net charge)
Hypotonic solutions
½ NS
The solute concentration is less than that of serum. Therefore, it shifts out of the intravascular compartment after administration.
Less solute per sterile water, draw in water from intracellular to cellular
(swelling of the cell)
Hypertonic solutions
D5 ½ NS, D5 NS, D10 W
The solute concentration is higher than that of serum. Therefore, it draws fluid into the intravascular spaces after administration. Although a hypertonic solution has more solutes than an adjacent solution it has less fluid.
Draw in fluids from tissue because of large molecules
(skinning of the cell)
