Diffusion

Water

Molality

Mass of solute per unit of volume

Particle size

Colloid solution

Sedimentation

Inflammation

Molarity

High polarity

Brownian motion

Sedimentation

Very slow

$\pi = iRTc$

Intracellular osmolarity sources

Hypertonic solution

The concentration of osmotically active particles in a solution

Dissociate into ions

Exchange of protons

7.5 - 8.0

Buffer solutions

Stable pH

Hydrogencarbonate buffer system

Osmosis is the movement of solvent molecules across a semipermeable membrane to equalize the concentration of solute on both sides. An example of osmosis in biological systems is the movement of water into and out of cells to maintain the cell's internal environment.

Osmotic pressure is represented by $π = iRTc$, where i is the number of particles formed from one molecule of solute, R is the universal gas constant, T is the thermodynamic temperature, and c is the molar concentration.

Cellular osmolarity is influenced by intracellular osmolarity sources, including small charged/polar inorganic ions and biopolymers, with the highest contribution coming from bound ions and molecules.

Isotonic, hypertonic, and hypotonic solutions have osmotic pressures identical to, higher than, and lower than that of human blood plasma, respectively.

Osmolarity is the concentration of osmotically active particles and can be calculated for solutions of electrolytes.

Electrolytes are substances that dissociate into ions in water, leading to ionic strength and interactions that cannot be described by ion concentrations alone.

Chemical reactions in aqueous solutions include acid-base reactions (e.g., HCl + NaOH → NaCl + H2O), oxidation-reduction reactions (e.g., Fe2+ + Cu2+ → Fe3+ + Cu), precipitation reactions (e.g., AgNO3 + NaCl → AgCl + NaNO3), and complex reactions.

Acid-base reactions involve the exchange of protons, and the pH of body fluids varies, ranging from 0.9 in gastric juice to 8.0 in pancreatic juice.

pH can be calculated for acids and bases, with strong acids and bases having simplified formulas compared to weak acids and bases.

Salt hydrolysis results in different pH effects based on the strength of the acid and base, and buffer solutions can prevent significant changes in pH after the addition of acids and bases.

Human blood has buffer systems such as hydrogencarbonate, phosphate, and plasma proteins, which help maintain a stable pH. The hydrogencarbonate buffer system acts to regulate excess $H^+$ and $OH^-$ ions and can be calculated using the Henderson-Hasselbach equation.

Molarity is the number of moles of solute in one liter of solution (mol/l, M), while molality is the number of moles of solute in one kilogram of solvent (mol/kg).

The four characteristics of water that make it an ideal solvent with respect to life are: high polarity (allowing for the solubility of salts, acids, bases, and many organic substances), high dielectric constant (facilitating the dissolution of polar solutes), relative high boiling temperature, and high heat capacity (which allows water to absorb and release large amounts of heat with minimal temperature change).

Mass concentration is the mass of solute per unit of volume (e.g. g/l) and is used for substances which do not have a defined composition (e.g. proteins, nucleic acids). Weight percent (w/w) is the mass of solute per mass of solution multiplied by 100, while volume percent (v/v) is the volume of solute per volume of solution multiplied by 100.

Solutions can be categorized as analytic (particle size < 1 nm, very fast particle movement, Brownian motion thermal motion, and ability to pass through all kinds of filters), colloid (particle size 1-1000 nm, very fast particle movement, Brownian motion thermal motion, and inability to pass through membrane filters), or crude (particle size > 1000 nm, very slow particle movement, any diffusion thermal motion, and inability to pass through membrane filters).

The separation of erythrocytes from plasma in a gravitation field can be observed using the FW – Fahraeus–Westergren test, which involves the sedimentation of erythrocytes. Increased values might indicate inflammation or cancer.

Blood can be categorized as an analytic solution (containing ions, nutrients, and metabolites), a colloid solution (containing proteins and lipoproteins), or a crude solution (containing erythrocytes, leukocytes, and platelets).

Osmotic pressure is the pressure that must be applied to a solution to prevent the inward flow of water across a semipermeable membrane. It is significant in biological systems for processes such as osmoregulation and maintenance of cell shape.

In colloid solutions, the particle movement is very fast, and the filter ability is limited as these particles do not pass through membrane filters. In crude solutions, the particle movement is very slow, and the particles do not pass through membrane filters.

The sedimentation of erythrocytes in a gravitation field, such as observed in the FW – Fahraeus–Westergren test, can indicate conditions such as inflammation or cancer when the values are increased.

Water's high polarity allows for the solubility of a wide range of substances, including salts, acids, bases, organic compounds, proteins, and nucleic acids. Its high dielectric constant and relative high boiling temperature contribute to its effectiveness as a solvent, while its high heat capacity allows it to absorb and release large amounts of heat with minimal temperature change, making it ideal for life-sustaining processes.

Analytic solutions have very fast particle movement and the ability to pass through all kinds of filters due to their small particle size and rapid particle motion.

Molarity is the number of moles of solute in one liter of solution, and its unit of measurement is mol/l or M.

The separation of erythrocytes from plasma in a gravitation field, such as observed in the FW – Fahraeus–Westergren test, can provide diagnostic information related to conditions such as inflammation or cancer when the sedimentation values are increased.