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Membrane Transport. Chp. 3, 5. Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - Active transport Chemical equilibrium Electrical equilibrium The membrane potential. Outline. Body Fluid Compartments. Figure 3-2.
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Membrane Transport • Chp. 3, 5
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Body Fluid Compartments Figure 3-2
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Cell Membrane: Function • Physical barrier • Gateway for exchange • Communication • Cell structure • Phospholipid bilayer
Cell Membrane: Structure The fluid mosaic model of a biological membrane Figure 3-4
Lipids Micelles Liposomes Sphingolipids Proteins Integral Peripheral Lipid-anchored Cell Membrane: Composition
Cell Membrane: Formation Membrane phospholipids form bilayers, micelles, or liposomes Figure 3-5a
Cell Membrane: Formation Figure 3-5b
Cell Membrane: Proteins The three types of membrane proteins: integral, peripheral, and lipid-anchored Figure 3-6
Cell Membrane Map of cell membrane components Figure 3-9
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Distribution of Epithelia in the Body Figure 3-24
Exchange Epithelia • Leaky junctions • Rapid transport • Oxygen • Carbon dioxide • Ions and fluids • Capillaries and lung alveoli
Exchange Epithelia Figure 3-25a
Transporting Epithelia • Exchange of ions and nutrients • Tight junctions • Intestine and kidney
Transporting Epithelia Figure 3-25b
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - diffusion - facilitated diffusion - osmosis - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Diffusion: Seven Properties • Passive process • High concentration to low concentration • Net movement until concentration is equal • Rapid over short distances • Directly related to temperature • Inversely related to molecular size • In open system or across a partition
Simple Diffusion Fick’s law of diffusion Figure 5-6
Permeable to: H2O Lipids Gases Small neutral molecules Impermeable to: Large molecules Charged molecules Cell membrane
Large molecules and charged molecules cannot cross the phospholipid bilayer. They have to use special channels to cross (movement well controlled) or They have to pass through spaces between cells (movement not so tightly controlled) Cell membrane permeability
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - diffusion - facilitated diffusion - osmosis - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - diffusion - facilitated diffusion - osmosis - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - diffusion - facilitated diffusion - osmosis - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Molecules are carried from low concentration to high conc. areas Active transport Figure 5-16
Fluid compartments Membrane structure Movement of electrolytes other solutes and water - Passive transport - diffusion - facilitated diffusion - osmosis - Active transport Chemical equilibrium Electrical equilibrium The membrane potential Outline
Chemical equilibrium • Compounds will move between the various fluid compartments depending their concentrations, permeability and the presence of carriers