Urinary diffusion

• Body fluids consist of intracellular fluid (within cells, consists of 2/3 of fluids) and extracellular fluid (includes interstitial fluid, plasma and lymph)
• Solvent is the liquid doing the dissolving. It is generally water in the body VS solute is the dissolved material (particles or gas)
• Concentration is the amount of solute in a set amount of solvent VS concentration gradient is the difference in concentration between 2 areas of solution
• Diffusion is a passive transport so it does not require energy, it requires a concentration gradient. The solutes move from high to low concentration until the equilibrium is reached.
• Simple diffusion requires a concentration gradient of solute to be present. It is used with lipid soluble or very small uncharged particles to cross the plasma membrane (lipid bilayer)
• Facilitated diffusion is used for substances who do not it through the membrane such as glucose and salt. It requires a carrier in the membrane but is still passive since the solute follows the concentration gradient
• Facilitated diffusion maximum transport speed depends on the number of carriers in the membrane. For example, insulin increases the number of carriers for glucose in the plasma membrane
• Many channels in facilitated diffusion are gated, meaning they can open or close, eg: ion channels for sodium, potassium or chloride ions
• Osmosis is a passive process meaning no energy is required. It represents the net movement of water from high to low concentration through the plasma membrane (selectively permeable membrane)
• If a cell wants to transport solutes against a concentration gradient, it requires active transport. Active transport requires a carrier called a pump and energy (ATP). It is critical for moving important ions such as the sodium potassium pump
• The sodium potassium pump moves solutes from low concentration to high concentration.