Review of Osmosis and Osmotic Equilibrium

A set of flashcards covering key concepts related to osmosis, osmotic equilibrium, and their physiological implications.

What is osmosis?

The flow of solvent molecules through a semi-permeable membrane from a region of lower solute concentration to a region of higher solute concentration.

What is osmotic pressure?

A measure of concentration that represents the exact pressure necessary to prevent osmosis from taking place.

What does the equation p = MRT represent?

It relates osmotic pressure (p) to molarity (M), the ideal gas constant (R), and temperature (T).

Differentiate between molarity and osmolarity.

Molarity measures the concentration of solute in solution, while osmolarity measures the total concentration of particles in solution, including dissociated ions.

What is the van’t Hoff factor?

The ratio of the actual number of particles in solution after dissociation to the number of formula units initially dissolved.

What is an isotonic solution with respect to red blood cells?

A solution that has the same osmotic pressure as red blood cells, such as 0.89% NaCl or 5% glucose.

What occurs when red blood cells are placed in a hypotonic solution?

Water moves into the cells, causing them to swell and potentially rupture (haemolysis).

What occurs when red blood cells are placed in a hypertonic solution?

Water moves from the cells to the surrounding solution, causing the cells to shrink (crenation).

What is the significance of osmolarity in intravenous solutions?

It ensures solutions are isotonic with blood to prevent cellular damage.

What is the normal range of blood serum osmolarity?

280 - 290 mosmol/L.

What is an example of a strong electrolyte?

Sodium chloride (NaCl) which dissociates into Na+ and Cl- ions.

What is an example of a nonelectrolyte?

Glucose, which does not dissociate into ions.

How does the concentration of blood plasma proteins relate to osmotic pressure?

Higher levels of proteins in blood compared to interstitial fluid create a higher osmotic pressure.

What is the effect of blood pressure on fluid movement at the arterial end of a capillary?

Blood pressure is higher than osmotic pressure, causing fluid and nutrients to move from blood into interstitial fluid.

What happens at the venous end of a capillary regarding osmotic and blood pressure?

Osmotic pressure is greater than blood pressure, allowing fluid to move from interstitial fluid back into the blood.

What is the osmolarity of a 0.1 M NaCl solution?

0.2 osmol/L due to dissociation into Na+ and Cl- ions.

What is the ideal gas constant (R) in osmotic pressure calculations?

0.08206 L atm K^{-1} mol^{-1}.

What is the effect of improper osmolarity in IV solutions?

It can lead to cellular damage or ineffective treatment.

How is osmolarity calculated for NaCl?

Osmolarity = i imes M, where i is the van’t Hoff factor and M is molarity.

What happens during hydration in a dilute solution?

Cations and anions are completely surrounded by water molecules.

What is a normal saline solution?

A 0.9% NaCl solution that is isotonic to red blood cells.

What happens when proteins dissociate in solution?

They increase the total number of particles, thereby affecting osmotic pressure.

How is the osmolarity of a 5% glucose solution calculated?

Osmolarity = 1 imes 0.28 = 0.28 osmol/L, as glucose does not dissociate.

What is the primary function of blood proteins?

To contribute to osmotic pressure and assist in nutrient transport.

What role does the capillary bed play in nutrient exchange?

It allows oxygen and nutrients to exit the bloodstream into the interstitial fluid and facilitates waste product return.

What is the consequence of excessive osmotic pressure in interstitial fluid?

It can lead to dehydration of interstitial spaces, affecting cell viability.

What factors determine the rate of diffusion in capillary beds?

Concentration gradients, osmotic pressure, and blood pressure.

Why are intravenous preparations made with isotonic solutions?

To maintain equilibrium and prevent cellular damage during infusion.

What happens to red blood cells in distilled water?

They undergo haemolysis due to being placed in a hypotonic solution.

How is molarity defined?

The number of moles of solute per liter of solution (mol/L).

What is crenation?

The shrinkage of red blood cells when placed in a hypertonic solution.

Why is it important for IV fluids to have the correct osmolarity?

To prevent osmotic imbalances that could damage tissues and cells.

Which cell type is primarily responsible for oxygen transport?

Red blood cells.

What is the significance of a 0.89% NaCl solution for patients?

It is isotonic and safe for intravenous infusion to maintain fluid balance.

What should be done when patients cannot swallow or are severely dehydrated?

Administer intravenous fluids that are isotonic.

What does the term hypotonic refer to?

A solution with a lower solute concentration compared to cells.

What does the term hypertonic refer to?

A solution with a higher solute concentration compared to cells.

What happens to fluid and nutrients at the arterial end of a capillary?

They move from blood into the interstitial fluid due to higher blood pressure.

What is the clinical implication of osmolarity comparisons?

They can indicate kidney function based on the osmolarity of blood and urine.

What is the primary force driving nutrients from blood into cells?

Osmotic pressure and diffusion due to concentration gradients.