PHSI 208 Chapter 3: PHSI 208.6 Chapter 3 Notes (VC2)
Document Summary
Membrane physiology (def): all signals from nervous system happen at the membrane level. Functional compartments: extracellular fluid; plasma, interstitial fluid. The ecf-icf dividing wall is the cell membrane. There are three main types of lipids: phospholipids, sphingolipids and cholesterol. In aqueous solution, they orient themselves so that the polar heads interact with water while non-polar tails hide. They arrange themselves so that their nonpolar tails are not in contact with aqueous solutions such as extracellular fluid. Amphipathic molecules, like the one demonstrated on the left can arrange themselves as phospholipid bilayers, micelles, or liposomes. Cell membrane functions: physical isolation: physical barrier separating intra and extracellular fluids. Refer to letters: peripheral proteins are non-covalently bonded with integral proteins (see circled portion), most integral membrane proteins have membrane-spanning alpha-helical domains of about 20 amino acids, some have multiple membrane-spanning domains. The more metabolically active a membrane is, the more proteins it contains. Therefore, inner mitochondrial membranes are the most metabolically active.
