Water balance part 4 and 5 Flashcards
Osmosis
movement of water through a semipermeable membrane
osmotic pressure exerted by particles is based on mass or number of particles per unit of volume
number of particles per unit of volume
each particle in solution exerts the same amount of pressure against a membrane regardless of mass. True or false?
True
Molar Concentration
the amount of substance per unit volume
Molal concentration
the amount of substance per unit mass of solvent
In what form is water in in the interstitial?
1) gel (proteoglycans and water)
2) rivulets of free fluid
3) free fluid vesicles
how are compartment volumes measured?
by determining the volume of distribution of a tracer substance
compartment volume equation:
Volume = the amount of tracer/ the concentration of tracer
What are two examples of tracers?
1) Ionics-enters other compartments- overestimation
2) Crystalloids-lack of full distribution in ECF- low estimate
Glomerular filtration rate can be used to measure what?
analyzes renal function
What happens to inulin in the glomerulus when H2O is reabsorbed?
Inulin increases
GFR = what?
the the plasma is cleared of a substance if that substance is freely filterable
What is diabetes insipidus?
the kidneys are unable to prevent the excretion of water so a large amount of dilute urine is excreted.
What are the two types of diabetes insipidus?
1) Diabetes insipidus centralis
2) Diabetes insipidus renalis
What are the two types of diabetes insipidus?
1) Diabetes insipidus centralis
2) Diabetes insipidus renalis
Diabetes insipidus centralis?
caused by a lack of ADH synthesis in the pituitary gland
Diabetes insipidus renalis?
ADH is produced but cannot act in the kidneys
Clinical signs of diabetes insipidus?
PU/PD, noctoria, urine test can show ADH level
How can the cell protect against volume fluctuations?
mechanosensors regulate ion flow in and out of cell
Insensible water loss
waterless that cannot be measured (sensed)
- water vapor exhaled
- skin (not sweat)
Sensible water loss
water loss that can be measured
- skin-sweat
- feces
- urine production
Hypovolemia
blood volume loss
Dehydration
reduced fluid volume (less than normal)
Hypertonic (During Dehydration)
- is the most common form of dehydration /water loss
- water loss exceed electrolyte loss
- ECF has increased osmolality
- increased osmolality of ICF
Isotonic (during dehydration)
water loss equals electrolyte loss
- hypovolemia
- decreased volume of ECF
- sweat, hemorrhage
Hypotonic (during dehydration)
loss of electrolytes exceeds loss of water
- not common
- osmolality of ECF decreases
- caused by kidney disease, diarrhea
Overhydration
fluid volume is greater than normal
-hypervolemia
