PHGY 209 Lecture Notes - Lecture 3: Lipid Bilayer, Plasmapheresis, Particle Size
30 Oct 2017
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Plasma exchange through gi tract, kidneys, skin, lungs. Our fo(cid:272)us" are the (cid:272)apillary (cid:449)all (cid:894)1 (cid:272)ell thi(cid:272)k(cid:895) and the cell membrane. Organelles have compartments dividing cells and have their own membranes. Function of cell membrane: support distinct composition of icf and isf, be selectively permeable. Highly permeable: h2o, lipid soluble substances, dissolved gases (o2, co2), small uncharged molecules. Impermeable to: very large molecules (they are stuck inside) Factors affecting movement across cell membrane: lipid solubility, particle size, electric charge, availability/number of carriers and ion channels (max capacity especially w/carriers) Passive: energy independent (no need for atp or any other energy: diffusion movement of solute particles resulting form random thermal molecular motion; as they collide, they disperse. Net flux of solute particles always occurs from a region of high concentration to one of lower concentration. A single cell will not change the extracellular solute concentration it has a much greater volume than a single cell.
