Renal 1 Flashcards
Constant (2)
of body fluid compartments are essential
for homeostasis:
volume and stable composition
Constant volume and stable composition
of body fluid compartments are essential
for homeostasis:
“A frequent problem in treating seriously
ill patients is…
maintaining adequate fluids
in one or both of the intracellular and
extracellular compartments.”
Water in =
Water out
Electrolytes in =
Electrolytes out
pH =
7.4
Fluid distribution in the body influences — concentrations
electrolyte
Electrolyte concentrations influence
fluid distribution in the body.
Na+
–Imbalance changes
vascular and total body
volumes
K+
–Imbalance alters
cardiac and neural functions
Ca++
–Imbalance alters (3)
skeletal muscle, cardiac, neural function and bone structure
H+ (mainly from metabolism)
–Imbalance alters
multiple systems
Total body water
volume is
42L,
~60% body
weight (kg)
Plasma & Interstitial fluid mix rapidly (except proteins): (2)
- Hydrostatic and colloid osmotic pressure via capillary pores is
main force. - Bulk flow
Fluid distribution between ICF & ECF determined by osmotic effect
of small solutes acting across cell membrane: (2)
- Na+ and Cl- (other anions) ≈ 90% of total ECF osmolarity
- K+ and other ions ≈ 90% of total ICF osmolarity.
Cell membrane: (2)
- high permeability to H2O;
- relative impermeability to small solutes (Na+, Cl- & other
electrolytes) .
Cell volume is at the
mercy of
ECF tonicity
ECF (2) Constantly
Challenged
Osmolarity and
Volume
Daily life (2)
Eat and drink
Do not eat and drink
skipped
Conditions/Illnesses (4)
Vomiting, diarrhea Burns and other causes of skin loss Heat-induced sweating Renal disease
Composition and volume of ECF change determines
composition and volume of fluid replacement
The kidneys regulate body
fluid volume and composition
by controlling (2)
ECF volume and
composition.
Edema
• Too much water in
tissues.
— edema
much more common
than —.
Extracellular
intracellular
Intracellular Edema
Causes: (3)
- Hyponatremia.
- Decreased metabolism (blood flow): Na+/K+
pump failure. - Inflammation (infection, burns) – increased
membrane permeability and leakage.