Physiology 2130 Lecture Notes - Lecture 4: Pressure Gradient, Osmotic Concentration, Osmosis

• School: Western University
• Department: Physiology
• Course: Physiology 2130
• Professor: Anita Woods

Document Summary

Osmosis: movement of water across a membrane in response to a solute concentration gradient, water moves to dilute the more concentrated solution, osmosis is affected by 3 things. Osmotic pressure: pressure applied to oppose the osmotic movement of water. In the previous example, the osmotic pressure would be the pressure needed to prevent the movement of water from a to b. Osmolarity: to calculate osmolarity we need to know. The number of moles of the substance in solution. Tonicity: the ability of a solution to cause osmosis across biological cell membranes, osmolarity of body fluids: 300mosm, hypotonic: lower osmolarity than body fluids, hypertonic: higher osmolarity than body fluids. Movement of ions: the plasma membrane can also control the movement of ions (such as na+) across its membrane, the movement of ions is affected by both the chemical and electrical gradients.