Fluids/Fluid Shifts Flashcards
Define:Diffusion
Move from area high concentration to area of low until concentrations are equal
Define:Facilitated Diffusion
Passive transport that allows substances to cross membranes with assistance of special transport proteins
Define: Active Transport
Movement of a substance across a cell membrane against its concentration gradient (from low to high concentration) – uses chemical energy of ATP (high-energy molecule that stores the energy we need to do just about everything we do; present in the cytoplasm and nucleoplasm of every cell
Name two electrolytes that utilize active transport?
Used by sodium and potassium to move in/out of cells
Define:Osmosis
Particles cross semipermeable membrane from area of low solute concentration to high
Define: Hydrostatic Pressure
Pressure exerted by a fluid at equilibrium due to the force of gravity; pressure of fluids at rest
Define: Osmotic Pressure
Pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane – minimum pressure to nullify osmosis
What is a colloid?
Large molecules don’t pass through semipermeable membranes – i.e. blood and blood products, albumin
What is a crystalloid?
Easily dissolved – may be electrolytes, such as dextrose – flow easily across semipermeable membranes allowing transfer into blood stream – distinguished by relative tonicity – IV fluids
Types of crystalloids?
Isotonic (250 – 375 mmol/L)
Hypotonic (less than 250 mmol/L)
Hypertonic (greater than 375 mmol/L)
What is an isotonic IV fluid?
no fluid shift because same concentration of solutes as plasma; remains in extracellular fluid and distributed between intravascular and interstitial compartments – normal saline, R/L, D5W (turns to hypotonic once the dextrose burns off in the body)
Name the 2 fluid compartments
Intracellular
Extracellular
Who am I: I make up the Intravascular (plasma),
Interstitial, Transcellular space
Extracellular Compartment
Who am I: I am the fluid compartment located inside the cells
Intracellular
Who am I: 1/3 of body weight, between cells (interstitial fluid), lymph, plasma, and transcellular fliud (small but important – cerebrospinal fluid, GI, pleural/synovial/peritoneal spaces)
Extracellular fluid
Compartment spacing: 1st Spacing
Normal distribution within ECF and ICF
What type of spacing am I: Edema
2nd Spacing
Type of spacing: Ascites
3rd Spacing
What type of spacing am I: Accumulation within the interstitial compartments
2nd Spacing
Edema forms but fluid is still available for physiological exchange between compartments
2nd Spacing
What is 3rd spacing?
Fluid accumulation in parts of the body where it’s not available for exchange between the different compartments
Ascites, tissue inflammation, some burns (type of blank spacing)
3rd spacing
Why would edema in burns be considered 3rd spacing?
With regard to severe burns, fluids may pool on the burn site (i.e. fluid lying outside of the interstitial tissue, exposed to evaporation) and cause depletion of the fluids in the first and second compartments
What happens in severe cases of ascites? What happens to the overall circulating volume?
In severe cases, fluid is shifted into peritoneal space along with protein and electrolytes causing a third spacing fluid shift which contributes to decrease in circulating volume.
What is Homeostasis?
State of equilibrium in the body
Naturally maintained by adaptive responses
Body fluids and electrolytes are maintained within narrow limits
Fill in the blank: Maintaining fluid (blank) in various compartments of body involves balancing fluid intake, absorption, distribution, and excretion
Homeostasis
