基础化学 教学chapter_2-20140917-7y.ppt

* * *  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * §3. Osmosis Example 2-9: Calculate the osmolarity of 9.00 g·L-1 NaCl solution and 50.0 g·L-1 glucose solution. Solution: NaCl ? Na+ + Cl- §3. Osmosis Osmolarities of osmotic active substance in normal blood plasma 2. Isotonic, hypertonic, and hypotonic solution §3. Osmosis The osmolarity of the solution is equal to that of the cell; the cell has its normal round shape with depressed center. Isotonic solution (等渗溶液) Cell membrane: a semipermeable membrane §3. Osmosis Hypotonic solution (低渗溶液) The osmolarity of the solution is less than that of the cell; the cell has a bloated shape. Hemolysis (溶血) §3. Osmosis Hypertonic solution (高渗溶液) The osmolarity of the solution is greater than that of the cell; the cell has collapsed. Embolism (栓塞) §3. Osmosis Isotonic solution: cos= 280 ? 320 mmol · L-1 Hypertonic solution: cos 320 mmol · L-1 Hypotonic solution: cos 280 mmol · L-1 Reference: blood plasma, cos=303.7 mmol · L-1 Clinical isotonic solution: NaCl: 9.0 g · L-1 Glucose: 50.0 g · L-1 Isotonic, hypertonic, and hypotonic solutions in medical sciences For the intravenous feeding (adding a nutrient solution to the venous (静脉) blood supply of a patient), it is necessary that the nutrient solution have exactly the osmotic pressure of blood plasma. §3. Osmosis The body has portions of organs that are at different osmotic pressures, and an active pumping mechanism is required to offset osmosis. For example, cells of the transparent tissue of the exterior eye, the cornea, have a more concentrated optical fluid than does the aqueous humor, a solution just behind the cornea. 3. Osmosis and transplantation of cornea (角膜移植) §3. Osmosis To prevent the cornea from taking up additional water from the aqueous humor, cells that pump water are located in the corneal tissue adjacent to the aqueous humor. Corneas that are to be stored and used fo