Overview of A&P1 Labs

1. Overview of A&P1 Labs • Lab Syllabus • Text is lab manual – bring it to each lab • Web of Life – Lab Worksheets/Resources • 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

2. Lab 1 • Membrane transport processes • Body Cavities, Abdominopelvic Quadrants, and Organs • Organ locations • Directional Terminology MDufilho

3. Membrane Transport Processes • What membrane are we talking about? • Why is it important to transport materials across the membrane? MDufilho

4. Membrane Transport • Plasma membranes selectively permeable • Some molecules pass through easily; some do not • Two ways substances cross membrane • Passive processes • Active processes MDufilho

5. 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 MDufilho

6. 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 MDufilho

7. 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 MDufilho

8. 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 PLAY Animation: Membrane Permeability MDufilho

9. 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 MDufilho

10. 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 MDufilho

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

12. 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 MDufilho

13. 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 MDufilho

14. 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. Right compartment: Left compartment: Solution with greater osmolarity Solution with lower osmolarity Both solutions have the same osmolarity: volume unchanged Solute Solute molecules (sugar) Freely permeable membrane MDufilho

15. 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 Solute molecules (sugar) Selectively permeable membrane MDufilho

16. Tonicity • Tonicity: Ability of solution to alter cell's water volume • Isotonic: Solution with same non-penetratingsolute concentration as cytosol • Hypertonic: Solution with higher non-penetrating solute concentration than cytosol • Hypotonic: Solution with lower non-penetrating solute concentration than cytosol MDufilho

17. Figure 3.9 The effect of solutions of varying tonicities on living red blood cells. Hypertonic solutions Isotonic solutions Hypotonic 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). MDufilho

18. 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 MDufilho