Lecture 04, 01 Sept 2005 Chapters 2, 3, and 10. Vertebrate Physiology ECOL 437 (aka MCB 437, VetSci 437) University of Arizona Fall 2005

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1 Lecture 04, 01 Sept 2005 Chapters 2, 3, and 10 Vertebrate Physiology ECOL 437 (aka MCB 437, VetSci 437) University of Arizona Fall 2005 instr: Kevin Bonine t.a.: Kristen Potter 1 Vertebrate Physiology 437 Chapter 2 1. Membranes and Biological Compounds 2. Enzymes Chapter 3 3. Water and Movement of Solutes Chapter Nervous System Introduction 2 1

2 Friday Physiology Seminars See course website for link to schedule 3 Lactate dehydrogenase 2 alleles killifish Hill et al

3 Membrane Signaling Hill et al Membrane Signaling Hill et al

4 Hill et al Membrane Signaling Membrane Signaling Hill et al

5 2 nd Messengers 1 cyclicamp 2 CyclicGMP 3 NO 4 DAG 5 IP 3 6 Calcium Hill et al Amplification Hill et al

6 Movement Across Membranes How does glucose cross membranes? Most tissues: Passive transport down [ ] gradient via carrier proteins In gut: 2 o active to move Glu against [ ] gradient into blood from food 11 Movement Across Membranes 1. Passive Diffusion (= simple diffusion) 2. Passive Transport (= facilitated diffusion) 3. Active Transport Transport (pore or carrier) may be highly selective Randall et al

7 Movement Across Membranes 1. Passive Diffusion (= simple diffusion) nonpolar/nonelectrolyte lipid soluble (steroid hormones) few H bonds ~smaller size rate depends on [ ] gradient No saturation 417 Randall 13et al Diffusion Fick Equation: J = D C 1 C 2 X J = net rate of diffusion D = diffusion coefficient (depends on permeability and Temp) C 1 C 2 = [gradient] X = distance separating C1 from C2 14 7

8 Hill et al What is a boundary layer? 16 8

9 Movement Across Membranes 1. Passive Diffusion (= simple diffusion) 2. Passive Transport (= facilitated diffusion) Down Electrochemical gradient A. pore B. carrier mediated pores show some saturation, but not as much as carriers Randall et al Movement Across Membranes 1. Passive Diffusion (= simple diffusion) 2. Passive Transport (= facilitated diffusion) 3. Active Transport (1 o, 2 o ) 417 Randall et al Randall et al Na/K ATPase Pump 18 9

10 Martin Wikelski, Princeton 19 Fernandina K.E.Bonine

11 El Nino lack of food Galapagos Marine Iguana (Iguanidae) Starvation b/c high cost of salt excretion Animals may lose 15% body length bone absorption Only adult vertebrate known to regularly shrink (astronauts) Largest animals die sexual selection natural selection (Most efficient salt glands known in reptiles) Amblyrhynchus cristatus 21 K.E.Bonine

12 Hill et al (See Pelis et al 2001) Hill et al

13 Movement Across Membranes 420 Randall et al Randall et al Movement Across Membranes 422 Randall et al

14 Movement Across Membranes 426 Randall et al How would you describe this movement across membrane? Randall et al Na/K ATPase Pump 28 14

15 Hill et al Leinhard et al

16 Ion Channels Ion selectivity Leaky channels (e.g., K) Voltagegated channels (e.g., Na, K, Ca) Ligandgated channels etc. charge ease of dehydration size 429 Randall et al Electrochemical equilibrium Fig 3.6, Hill et al

17 Osmotic Properties of Cells and Relative Ion Concentrations K Ca Ca Na K Na Cl Cl 412 Randall et al Permeabilities K >> Na ; Cl A (includes proteins, phosphate groups, etc.) 33 Electrogenic vs. Electroneutral Hill et al

18 How does water move across membranes? aquaporins 35 Movement Across Membranes Iso Hypo osmotic Hyper In specific tissues and cells: Iso Hypo tonic Hyper Movement of water 414 Randall et al

19 Osmotic Properties of Cells and Relative Ion Concentrations K Ca Ca Na K Na Cl Cl 412 Randall et al Hypertonic Cell Contents 416 Randall et al Colligative Properties Osmotic Pressure Freezing Point Water Vapor Pressure (boiling point; evaporation) Hill et al

20 Hill et al x Osmolarity 1 osmolar solution (Osm) has 1 Avogadro s number of dissolved particles/liter solvent 1 milliosmolar solution (mosm) has Avogadro s number of dissolved particles/liter solvent 40 20

21 What osmolarity do you get if you add 6 x molecules of glucose to a liter of water? What osmolarity do you get if you add 6 x molecules of table salt to a liter of water? NaCl (strong electrolyte) 41 Hill et al

22 Difference in osmotic potential Rate of Osmosis = K П 1 П 2 X Proportionality Coefficient (~ permeability and temp) Distance between solutions 43 Osmotic Pressure Vs. Hydrostatic Pressure 44 22

23 Movement Across Membranes Electrochemical Gradient Electrical gradient Concentration gradient K K Electrochemical equilibrium Equilibrium potential (E x in mv) when [X] gradient = electrical gradient Na Na 45 Equilibrium potential (E x in mv) Every ion s goal in life is to make the membrane potential equal its own equilibrium potential (E x in mv) 46 23

24 p. 214, Silverthorn nd ed. Human Physiology. Prentice Hall 47 Nervous System Comprises Neurons/ Nerve Cells Glial Cells (support) Signalling via combination of Electrical and Chemical Integrate information AFFERENT Coordinate Response EFFERENT Randall et al