Water Transport Osmosis Flashcards
Where solute concentration is high and osmolarity is high the concentration of water is _____ (high/low)? What is normal osmolarity in a lab test?
Water is Low. Normal osmolarity is 300 mOsm/L
Total Body Water in liters is what percentage of Body weight? For a standardized patient weighing 70Kg how many liters of water is their TBW?
~60%. The standard patient would be 42L of water.
Intracellular fluid is what fraction of Total Body Water? Or what percent of body weight? What is the amount of fluid in a standard 70Kg patient
2/3 of TBW. Or 40% of body weight. This comes out to be 28L of fluid.
The extracellular fluid is what percent of Total Body Water? Or what percent of body weight? What is the amount of fluid in a standard 70Kg patient.
1/3 of TBW. Or 20% of body weight. This is 14L of fluid.
What is the 60-40-20 rule?
TBW is 60% of body weight. The Intracellular fluid is 40% of total body weight. The Extracellular fluid is 20% of total body weight.
What two compartments is the ECF distributed in?
The compartments are either inside or outside of the vaculature. The intravascular fluid is approximately 7% of body weight (or 5L for a 70kg adult). The extravascular fluid is interstitial fluid and is 75% of the ECF or about 11L.
How is ECF regulated? How is ICF regulated?
ECF is regulated within normal limits by balancing the excretion of water by the kidney to match the consump[tion of water by the mouth. ICF is regulated within narrow limits by solute transport mechanisms and ultimately osmosis. Optimal concentration of intracellular solutes is essential for function.
Aquaporins mediate water transport by a process known as ______. They do/ do not allow solutes to cross the membrane?
Facilitated diffusion and they DO NOT allow solute transport.
A low osmolarity means what in terms of chemical potential and water concentration?
The chemical potential is high and the concentration of water is high. Water would move from this area to one of high osmolarity and lower chemical potential.
What would be the effect of adding water to the ECF of a patient on the ECF and ICF?
It would increase ECF volume and decrease ECF osmolarity. Water would move into the ICF and increase ICF volume and dilute its osmolarity.
What would be the effect of adding an isotonic saline solution to the ECF of a patient on the ECF and ICF?
It would increase ECF without changing osmolarity. It would have no effect on the ICF volume and osmolarity.
What would be the effect of adding a hypertonic saline solution to the ECF of a patient on the ECF and ICF?
It would increase the osmolarity of both the ICF and ECF as well as to decrease ICF volume and increase ECF volume.
What do cells try to always keep constant, volume or osmolarity?
Cells try to keep a constant volume. They permit a change in ICF osmolarity while maintaining ICF volume constant in order to maintain a constant ICF concentration of regulatory factors import for normal cell function.
