PHYSIO-s10_04 - 1/31/2010 BIOL 260: Human Physiology Human...

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Unformatted text preview: 1/31/2010 BIOL 260: Human Physiology Human Spring 2010 Spring M, Feb. 1, 2010 Feb. www.smccd.edu/accounts/staplesn/biol260 1. Pre-Lab Writeups: Be sure to prepare before each Monday Lab W riteups Be before each Monday or Wednesday labs (for WHOLE week!)!! or Wednesday – (What? Why? How? are we doing in the lab??) 2. This Week: NEW Lab Exercise 4 (Reflexes!), and Ex. 2. 3. Handouts for NEW EXPERMENT 4!! (Wear shorts!) Handouts (Wear • Practice quiz will be posted on Webaccess/mrooms THIS week!! Practice Webaccess/mrooms 4. Lab Expt. 1 report (“Homeostasis”) due THIS WEEK!!.: a) b) c) DUE IN LAB!!! Brief introduction, data and analysis (graphs and explanations), conclusions (answer questions from the Cañada Physiology website) • Graph with EXCEL, “Create-A-Graph”**, or by hand on graph paper. Graph Write as a group (3-5)!! … Typed! With clearly-labeled, correct graphs. 5)!! 1. Describe how cellular receptors and intercellular signals modulate/ regulate responses to Describe stimuli. (how do cells respond differently to the same signal?) stimuli 2. Describe Cannon’s postulates on the maintenance of homeostatic/ homeodynamic postulates homeodynamic systems. 3. Citing specific examples, compare and contrast positive and negative feedback loops that Citing positive that control reflex pathways. control REVIEW TODAY: Students should be able to…. 1. Describe and diagram membrane structure. Explain some functions of at Describe membrane Explain least 5 types of membrane components. types 2. Compare and contrast the various methods of passive (2) and active (3) Compare membrane transport. membrane 3. Using diagrams, compare and contrast chemical (tonicity) and electrical Using equilibrium in cells. What are the uses of disequilibrium? equilibrium 4. Define and describe resting membrane potential. How is it maintained, Define resting How and why is it important for cell function? and 1 1/31/2010 Mass Balance in the Body • Clearance – Rate at which a molecule Rate disappears from the body disappears – Mass flow = concentration Mass volume flow • Homeostasis Homeostasis equilibrium!! – Osmotic equilibrium – Chemical disequilibrium – Electrical disequilibrium Figure 5-2 Homeostasis: Ionic Solutes Figure 5-3b 2 1/31/2010 Diffusion: Map of Membrane Transport Diffusion: Map Passive: Active: MEDIATED BULK Figure 5-4 Membranes are selectively permeable Membranes: two meanings • Membranous tissues: Membranous – Example: pericardial membrane – Epithelial tissues: one to many cells thick • Cell Membranes (plasmalemma) enclose cells Figure 5-1 (2004): Membranes in the body (2004): 3 1/31/2010 Cell Membranes: Overview 1. Cell structure & support 2. Barrier isolates cell Barrier (impermeable) (impermeable) a) Chemically b) Physically 3. Regulates exchange Regulates (semipermeable) 4. Cell communication Figure 3-4: The fluid mosaic 4: model of the membrane model 5.1) Membrane Structure • Lipids: Lipids: – Phospholipid bilayer and cholesterol • Membrane proteins: – Peripheral (associated) – Integral • A. Structural – bind cytoskeleton and ECM A. Structural • B. Bind specific Ligands: enzymes, signal receptors B. Ligands enzymes signal • C. Transporters….. C. Transporters 4 1/31/2010 Membrane Transporters: Overview Membrane Transporters Fig. 5-9: Transport proteins of the cell membrane Transporter Proteins: Transporter Move Products Through Membrane Move 1. Channel proteins a) Open b) Gated 2. Carrier proteins a) Bind to substrate b) Slower transport Fig. 5-9: Transport proteins of the 9: cell membrane cell 5 1/31/2010 Transporter Proteins: Transporter Channels – Open & Gated Figure 5-11: Gating of channel proteins 11: 5.2) Body Fluid 5.2) Compartments Compartments • Intracellular Intracellular (ICF) (ICF) • Extracellular Extracellular (ECF) (ECF) – Interstitial – Plasma Figure 5-13 (2004): Body fluid compartments 6 1/31/2010 Passive & down a concentration gradient Passive • “Stops” at Equilibrium = no NET movement at Equilibrium • Rate factors: Rate – membrane, temperature, distance, & size. 5.3) Diffusion: 5.3) Diffusion Figure 5-6: Fick’s law of 6: Fick law diffusion Carrier Mediated Transport: Transport: Can be Passive or Active Can 1. Uniport 1. 2. Cotransport a)Symport b)Antiport Figure 5-9: Types of carrier-mediated transport 3. Proteins: a) Specificity b) Competition c) Saturation!!! 7 1/31/2010 A. Passive: Facilitated A. Diffusion Diffusion • Uses transport proteins (Channels or Carriers) • Passive Diffusion to Equilibrium Figure 5- 12: Diffusion stops at equilibrium Facilitated Diffusion Figure 5-12: Diffusion of glucose into cells 12: 8 1/31/2010 B. Primary Active Transport: B. Pumps Products Pumps • Uses ATP to to move products move • Up a Up concentration gradient gradient – Low high Low Figure 5-13: The Na+ - K+ -ATPase Primary Active Transport: Primary ATP-Powered Protein Pumps ATP Na+/K+ Pump!! Figure 5-14: 14: Mechanism of the Na+ - K+ -ATPase Na 9 1/31/2010 C. Secondary Active Transport: Uses Kinetic Energy of [ion] Uses • Cotransports –Symport • [Ion] restored –using ATP using Figure 5-15: Sodium-glucose symporter glucose symporter Energy Transfer: Review • Cell metabolism Cell (Ch. 4) (Ch. • Membrane Membrane transport (Ch. 5) (Ch. • ** COUPLING – Exergonic processes release processes energy energy – Released energy Released absorbed by Endergonic Endergonic processes • Proceed!! Figure 5-19: Energy transfer in living cells 10 1/31/2010 D. Vesicles in Membrane Transport D. • Bulk Transport Bulk Moves: Moves: – particles particles – Large Large molecules molecules • Phagosome: – Fusion with Fusion lysosome lysosome • Phagocytes Phagocytes Figure 5-20 E. Endocytosis & Exocytosis: E. Endocytosis Exocytosis VacuoleTransport VacuoleTransport • ENDOCYTOSIS: ENDOCYTOSIS: – Pinocytosis: non-selective; small particles – Phagocytosis: non-selective; large selective; particles particles – Receptor mediated Endocytosis: Receptor Endocytosis • specific substrate (ligand) only 11 1/31/2010 Endocytosis & Exocytosis: Exocytosis Transport & Membrane Cycling Transport Figure 5-21: 21: ReceptorReceptor mediated mediated endocytosis endocytosis and exocytosis and exocytosis F. Transepithelial & F. Transepithelial Transcytosis Transcytosis 1. Cross two membranes a) Apical (lumenal side) b) Basolateral (ECF side) 2. Absorption: lumen to ECF 3. Secretion: ECF to ECF lumen/surface lumen/surface 12 1/31/2010 1. Transepithelial Transport 1. Transepithelial Figure 5-26: Transepithelial transport of glucose 26: Transepithelial Figure 5-22 2. Transcytosis 2. Transcytosis Figure 5-24: Transcytosis across the capillary endothelium 24: Transcytosis 13 1/31/2010 Distribution of Water and Solutes Distribution in the Body Compartments in • About 60% of body About weight is water weight • 67% water = 67% intracellular intracellular • 33% water = 33% extracellular extracellular – 25% = interstitial – 8% = plasma • % varies slightly with varies gender and age gender Figure 5-25: Distribution of volume in the 25: body fluid compartments body 5.4) Osmosis & Osmotic 5.4) Osmosis Osmotic Equilibrium Equilibrium 1. W ater freely crosses Water membranes membranes 2. Osmotic pressure (mm Hg, atm) Osmotic atm 3. Osmolarity – Molarity x # particles in particles solution/molecule (osm/L) solution/molecule 4. Osmolality – using body wt. – Milliosmoles solute/kg water 5. Comparing two solutions a) Isosmotic (same) b) Hyperosmotic (more) c) Hyposmotic (less) Figure 5-26: Osmosis and osmotic pressure 14 1/31/2010 A. Tonicity: How a Cell A. Tonicity Reacts in a Solution Reacts • Depends on Depends osmolarity, but also osmolarity but permeability of permeability of solutes solutes – = measure of the measure effect on the cell !!! effect • Penetrating solute • Non-penetrating solute ******************** 1) Isotonic cell same 2) Hypertonic cell shrivels 28a, 3) Hypotonic cell swells Figure 5-28a, b: Tonicity depends on the relative concentrations of nonpenetrating solutes nonpenetrating Tonicity: How a Cell Tonicity: Reacts in a Solution Reacts • Penetrating solutes Penetrating can move and disrupt the chemical / osmotic equilibrium!! osmotic Figure 5-28c, d: Tonicity depends 28c, on the relative concentrations of nonpenetrating solutes nonpenetrating 15 1/31/2010 B. Electrical Disequilibrium • Separation of charged ions – Membrane insulates – Potential = stored energy; required to keep charges separate Potential stored – Conduction of signal – when broken locally Conduction • Electrochemical gradient Figure 5-29: Separation of electrical charge 29: C. Membrane Potentials: Change with Permeability Change 1. Resting 2. Equilibrium Equilibrium 3. Channel opening 3. a) Voltage gated Voltage b) ATP gated (leak) b) ATP 16 ...
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