Fluid Distribution Flashcards
What percentage of water are men and women
Men - 60%
Women - 50%
What are the approximate values of fluid in the body compartments
Intracellular - 40% of body weight.
Extracellular - 20% of body weight. It consists of interstitial fluid (80%) and plasma (20%)
What is a non-electrolyte?
Molecules usually have covalent bonds which prevents them from dissociating in solutions. Therefore most non-electrolytes are organic molecules
What are electrolytes?
Chemical compounds that do dissociate into ions in water. Therefore they can conduct an electrical current. Typically these are ionised salts
Why do electrolytes have greater osmotic power than non-electrolytes?
Electrolytes dissociated into at least two ions whereas the non-electrolyte will remain undissociated and therefore only have 1 .
Contract the composition of ICF and ECF
ECF - high concs of sodium and chloride
ICF - high concs of potassium and phosphate
What causes fluid to move between the fluid compartments?
Hydrostatic pressure,
Osmotic Gradient,
the ICF volume is determined by the ECF solute concentration
What are the routes by which the body gains and loses water
Intake via ingested fluid and foods and some via metabolic water.
Output - Vaporises in lungs, diffuses through skin, perspiration, faeces and largely excreted by kidneys in urine
draw a flow chart explaining the thirst mechanism
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explain the mechanisms and consequences of ADH release
- Decrease in ECF solute concentration inhibits ADH release whereas an increase in ECF solute concentration causes release of ADH. ADH increases reabsorption of water in kidney tubules, increasing volume of ECF
What are the common causes of disturbances in water balance
Causes - Dehydration, oedema and hypotonic hydration.
What are signs, symptoms and consequences of dehydration
Sticky oral mucosa, thirst, dry flushed skin and decreased urine output. It can later cause weight loss, mental confusion and fever. Consequences - it may lead to hypovolaemic shock
