PCB 3703CHuman PhysiologySummer B 2013Chapter 1 PowerPoint Outline-Cell: Basic structural and functional units of life; includes all living organisms. (Unicellular/ Multi-Cellular.)Structure of a Cell:(1) Plasma Membrane(2) Cytoplasm(3) Nucleus(1)Plasma Membrane- Plasmalemma; outer thin and flexible membrane of the cell; separates the intracellular from extracellular area (fluids.) Selective permeability between intra- and extracellular regions. Structure of Plasma Membrane: Composed of double later of lipids; Phospholipids, cholesterol,and glycolipids,with proteins embedded within. (Contains both Hydrophilic/ Hydrophobic regions)A.Phospholipids- Mot abundant lipids in plasma membrane; 1.Hydrophilic Heads; Polar; contain Nitrogenous cmpd, phosphate bridge and glycerol, and attached to water (main constituent of intra- and extracellular fluids)2.Hydrophobic Tails: Non-polar; made up of Saturday (solid) fatty acids; align in the center of the membrane.B.Membrane Proteins; imbed the plasma membrane, through both layers of lipids1.Integral Proteins-Most abundant proteins of membrane; can be transmembrane (imbed entire membrane). a.Function:Acts as a receptor site. 2.Peripheral Protein- Found in Cytoplasmic side.a.Function:Support by network of filaments.3.Glycocalyx-(sugar cover/cell coat) short chain of carbohydrates produced by corneal epithelial surface cells; projected from external glycoproteins or glycolipids. a.Function:Cell-to-Cell binding and recognition; bind mucins onto the corneal surface. Functions of the Plasma Membrane-1.Serves as an external cell barrier against substances and forces outside the cell.2.External proteins act as receptors (Integral) and in Cell-to-Cell recognition. (Glycocalyx)3.Act in transport of substances into or out of the cell. Properties of Plasma Membrane-A.Selective movements of substances across the plasma membrane1.Passive Process-Substances pass freely with concentration gradient (More conc. To less conc. Region.) NO ATP.a.Diffusion- Movement of small, uncharged molecules (Oxygen, Co2, and fat soluble molecules)
2.Active Process- Substances move againsta concentration gradient from Low conc. To high conc., ATP needed.a.Active Transport-Larger, water-soluble and charged molecules (glucose, AA, and ions) transported by a pump with integral proteins. 3.Vesicular (bulk) transport- Pass large particles and macromolecules; exocytosis andendocytosis. a.Exocytosis: Membrane-Lined cytoplasmic vesicles (vSNAREs) join with plasma membrane (tSNAREs) to release contents outside the cell.1.Mucus and Protein secretion from glands.b.Endocytosis: Infolding of plasma membrane by clathrin protein to enclose large molecules into cytoplasmic vesicles, and bring into the cell. 1.Phagocytosis, (Cell eating); plasma membrane forms membranous vesicle, phagosome, to engulf macromolecules, with lysosomes (white blood cells) forenzymatic break down.
You've reached the end of your free preview.
Want to read all 4 pages?
- Spring '07