Overview of A&P1 Labs Lab Syllabus Text is lab manual – bring it to each lab Web of Life – Lab Worksheets/ResourcesWeb of Life Quizzes – weekly, oral/written format –Do not be late – questions not repeated –No Make-ups –12 taken, 10 best averaged Work as a team with your table Access to Lab Clean up MDufilho 8/24/20121

Lab 1 Membrane transport processes Body Cavities, Abdominopelvic Quadrants, and Organs Organ locations Directional Terminology 8/24/2012MDufilho2

Membrane Transport Processes What membrane are we talking about? Why is it important to transport materials across the membrane? 8/24/2012MDufilho3

Membrane Transport Plasma membranes selectively permeableselectively permeable –Some molecules pass through easily; some do not Two ways substances cross membrane –Passive processes –Active processes 8/24/20124

MDufilho Types of Membrane Transport Passive processes –No cellular energy (ATP) required –Substance moves down its concentration gradient Active processes –Energy (ATP) required –Occurs only in living cell membranes 8/24/20125

MDufilho Passive Processes Two types of passive transport –Diffusion Simple diffusion Carrier- and channel-mediated facilitated diffusion Osmosis –Filtration Usually across capillary walls The ones we will do in lab today are diffusion, osmosis and filtration 8/24/20126

MDufilho Passive Processes: Diffusion Collisions cause molecules to move down or with their concentration gradient –Difference in concentration between two areas Speed influenced by molecule size and temperature This can occur in a air, water and even though a membrane Video clip 8/24/20127

MDufilho PLAY Animation: Membrane Permeability Passive Processes Molecule will passively diffuse through membrane if –It is lipid soluble oxygen, carbon dioxide –Small enough to pass through membrane channels –Assisted by carrier molecule 8/24/20128

MDufilho Figure 3.7a Diffusion through the plasma membrane. Extracellular fluid Lipid- soluble solutes Cytoplasm Simple diffusion of fat-soluble molecules directly through the phospholipid bilayer 8/24/20129

MDufilho Passive Processes: Osmosis Movement of solvent (e.g., water) across selectively permeable membrane Water diffuses through plasma membranes –Through lipid bilayer –Through specific water channels called aquaporins (AQPs) Occurs when water concentration different on the two sides of a membrane 8/24/201210

MDufilho Figure 3.7d Diffusion through the plasma membrane. Osmosis, diffusion of a solvent such as water through a specific channel protein (aquaporin) or through the lipid bilayer Water molecules Lipid bilayer Aquaporin 8/24/201211

MDufilho Passive Processes: Osmosis Water concentration varies with number of solute particles because solute particles displace water molecules Osmolarity - Measure of total concentration of solute particles Water moves by osmosis until hydrostatic pressure (back pressure of water on membrane) and osmotic pressure (tendency of water to move into cell by osmosis) equalize Osmosis Video 8/24/201212

MDufilho Passive Processes: Osmosis When solutions of different osmolarity are separated by membrane permeable to all molecules, both solutes and water cross membrane until equilibrium reached When solutions of different osmolarity are separated by membrane impermeable to solutes, osmosis occurs until equilibrium reached 8/24/201213

MDufilho Figure 3.8a Influence of membrane permeability on diffusion and osmosis. Membrane permeable to both solutes and water Solute and water molecules move down their concentration gradients in opposite directions. Fluid volume remains the same in both compartments. Left compartment: Right compartment: Solution with lower osmolarity Solution with greater osmolarity Both solutions have the same osmolarity: volume unchanged Solute Freely permeable membrane Solute molecules (sugar) 8/24/201214

MDufilho Figure 3.8b Influence of membrane permeability on diffusion and osmosis. Membrane permeable to water, impermeable to solutes Solute molecules are prevented from moving but water moves by osmosis. Volume increases in the compartment with the higher osmolarity. Both solutions have identical osmolarity, but volume of the solution on the right is greater because only water is free to move Left compartment Right compartment Selectively permeable membrane Solute molecules (sugar) 8/24/201215

Tonicity Tonicity: Ability of solution to alter cell's water volume –Isotonic: Solution with same non-penetrating solute concentration as cytosol –Hypertonic: Solution with higher non- penetrating solute concentration than cytosol –Hypotonic: Solution with lower non- penetrating solute concentration than cytosol 8/24/2012MDufilho16

Figure 3.9 The effect of solutions of varying tonicities on living red blood cells. Isotonic solutions Cells retain their normal size and shape in isotonic solutions (same solute/water concentration as inside cells; water moves in and out). Cells lose water by osmosis and shrink in a hypertonic solution (contains a higher concentration of solutes than are present inside the cells). Cells take on water by osmosis until they become bloated and burst (lyse) in a hypotonic solution (contains a lower concentration of solutes than are present inside cells). Hypertonic solutions Hypotonic solutions 8/24/2012MDufilho17

Lab 1 - Procedure Start Osmosis procedure A or B – not both – takes about an hour to complete Start diffusion demo – takes about 30 min to complete Group Work – I hr –Learn internal organs/ abdominopelvic quadrants with mannequins –Learn Directional Terminology Start filtration demo Read results of osmosis and diffusion demos and answer questions 8/24/2012MDufilho18