PHYSIO-s10_03 - 1/26/2010 BIOL 260: Human Physiology Human...

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Unformatted text preview: 1/26/2010 BIOL 260: Human Physiology Human Spring 2010 W, Jan. 27, 2010 Spring Jan. Dr. Nathan Staples (Ph.D., UCSB 2002) Dr. (Ph.D., 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: Graphing practice, & Lab Exercises 1 & 2. Graphing 3. Handouts for NEW EXPERMENT 4!! (Wear shorts!) Handouts (Wear • Available this WEDNESDAY!!!! (for next week’s lab) 4. Lab Expt. 1 report (“Homeostasis”) due NEXT Labtime!!.: due Labtime a) b) Brief introduction, data and analysis (graphs and explanations), conclusions (answer questions from the Cañada Physiology website) Write as a group (3-5)!! … Typed! With clearly-labeled, correct graphs. 5)!! REVIEW 1. Citing examples, explain the importance of structure-function relationships and homeostasis Citing structure in physiology/biology. 2. Describe 5 types of intercellular communication. (2 classes) Describe types of intercellular 3. Describe and give an example of each of the 5 steps of a cellular signal pathway. Describe steps of cellular TODAY: Students should be able to…. 1. Describe and give an example of each of the 5 steps of a cellular signal Describe pathways. pathways 2. Describe how cellular receptors and intercellular signals modulate/ Describe regulate responses to stimuli. (how do cells respond differently to the same signal?) regulate 3. Describe Cannon’s postulates on the maintenance of homeostatic/ postulates homeodynamic systems. homeodynamic 4. Citing specific examples, compare and contrast positive and negative Citing feedback loops that control reflex pathways. feedback 1 1/26/2010 C. Signal Amplification** • Small signal produces Small large cell response large – Cytokines – peptides – Eicosanoids – lipids • Amplification enzyme • Cascade – One ligand iis amplified One ligand s into many intracellular molecules!!! molecules!!! Figure 6-7: Signal amplification D. Example Signal Pathway: D. GPCR GPCR 1. Membrane-spanning proteins spanning (G-protein coupled receptors) (G 2. Cytoplasmic tail linked to G protein, a Cytoplasmic protein three-part transducer molecule three part 3. When G proteins are activated, they 3. When proteins a) Open ion channels in the membrane b) Alter enzyme activity on the cytoplasmic Alter side of the membrane side 2 1/26/2010 1. GPCR: Adenylyl Cyclase-cAMP 1. Adenylyl The G proteincoupled coupled adenylyl adenylyl cyclase-cAMP system system Figure 6-11 2. GPCR: The Phospholipase C System The Phospholipase Figure 6-12 Figure 3 1/26/2010 E. Modulation of Signal E. Pathways by Ligands Ligands • Multiple ligands Multiple ligands • Agonist - turn on turn receptor receptor • Antagonist - block block receptor activity receptor Figure 6-17: Agonists and antagonists F. (Signal Pathways) F. Modulation by Receptors Modulation 1. Multiple receptors for a ligand: eg: epinephrine for ligand a) Alpha receptor – vasoconstriction (intestinal walls) Alpha b) Beta receptor – vasodilation (skeletal muscle) Beta 2. Receptor up-regulation: Grow more receptors Receptor up 3. Receptor down-regulation: Grow fewer receptor Receptor down a) Excess stimulation b) Drug tolerance 4. Endocytosis of ligand & receptor….. of ligand 4 1/26/2010 Modulation by Receptors Figure 6-18: Target response depends on the target receptor 6.3) Homeostasis and 6.3) “Homeodynamic” • Walter Cannon proposed parameters Walter under homeostatic control (environmental, under (environmental, materials cells need, internal secretions) materials • • Cannon's Postulates (concepts): PROPERTIES of Homeostatic Systems: 1. Nervous regulation of internal Nervous environment environment 2. Tonic llevel of activity – “how much”? evel ** Not ON or OFF! ** ** – Regulated by FREQUENCY of nerve Regulated input/firing. input/firing. Figure 6-19 3. Antagonistic controls – opposing signals controls 4. Chemical signals can have different Chemical effects on different tissues effects • receptors 5 1/26/2010 Tonic vs. Antagonistic Control • NOT just ON or OFF! Figure 6-20: Tonic control 20: A. Control Pathways • Maintain homeostasis • Local– paracrines • Long-distance – reflex control distance – – – – Nervous Nervous Endocrine Cytokines – autocrine, paracrine, endocrine activities Cytokines paracrine Some = SYSTEMIC (body-wide responses) Some SYSTEMIC • Reflex = llong distance pathway that uses nervous, ong endocrine, or both systems to receive input of a change, integrate the information, and respond appropriately. integrate 6 1/26/2010 Control Pathways Figure 6-22: Comparison of local and reflex control B. Reflex Control Feedback loop STIMULUS STIMULUS 1. Stimulus 2. Sensory receptor 3. 4. 5. Afferent path Integration center Efferent path SENSOR or RECEPTOR AFFERENT PATHWAY Response loop INTEGRATING CENTER EFFERENT PATHWAY 6. Effector- target cell/tissue 7. Response (feedback loop) Figure 6-23: Steps of a reflex pathway 23: TARGET or EFFECTOR RESPONSE 7 1/26/2010 Types of Receptors: Types Membrane, CNS & Peripheral Membrane, Figure 6-24: Multiple meanings of the word receptor 6.4) Homeostatic Setpoint 6.4) Setpoint • Homeostatic range -oscillation around setpoint Homeostatic oscillation setpoint • Change in setpoint = body’s “normal” levels; can Change setpoint levels; change change – Acclimatization • natural adaptation – Acclimation • refers to induced refers adaptation; artificial, in-llab ab artificial, situation situation – Biorhythms Figure 6-26: Oscillation around the setpoint 26: s etpoint 8 1/26/2010 A. Feedback Loops 1. Negative: are homeostatic !! – Response slows stimulation – Return to optimal range; stabilize the regulated Return variable! variable! – Eg: shivering to heat the body; when body temp rises, shivering the stimulus (cold) is removed, and the response stops the 2. Positive: stimulation drives more stimulation – Not homeostatic – External change stops cycle (eg: birth) 3. Feed forward: prepares body for change – Eg: Visual, olfactory stimuli salivation; stomach HCl Visual, salivation; HCl Feedback Loops Figure 6-26: Negative and positive feedback 9 1/26/2010 B. Positive B. Feedback Loop Loop Figure 6-28: A positive feedback loop 28: Complexity and Modulation of Control Systems of NEURAL or ENDOCRINE? 1. Specificity – Nerve path/anatomy, vs. Nerve receptor (more cells, more places!) (more 2. Nature of signal – Electrical/chemical, vs. hormone 3. Speed – Fast, vs. slow 4. Duration – Short vs. long 5. Stimulation intensity – Same/frequency, vs. [hormone] Figure 6-30: Control pathways 10 1/26/2010 Review of Review Control Pathways Pathways Figure 6-31: Some basic Some patterns of nervous, endocrine, and neuroendocrine neuroendocrine control control pathways pathways Ch. 6: Summary 1. Integration of systems uses local, endocrine and Integration nervous communications nervous 2. Signals travel via diffusion, gap junctions, axons, Signals and blood to target cells and 3. Receptor types and functions: binding, transduction, Receptor amplification, activation, cell responses amplification, 4. Receptors are modulated by competition, specificity, Receptors blocking, up– and down–regulation (tonic) blocking, 5. Concepts of homeostasis (homeodynamics) 6. Reflex control pathways, types, feedback and their Reflex regulation regulation 11 1/26/2010 Chapter 5 Membrane Membrane Dynamics Dynamics Mass Balance in the Body • Clearance 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 Figure 5-2 – Electrical disequilibrium 12 1/26/2010 Homeostasis: Ionic Solutes Figure 5-3b Diffusion: Map of Membrane Diffusion: Transport Transport Figure 5-4 Membranes are selectively permeable 13 1/26/2010 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): Cell Membranes: Overview 1. Cell structure & support 1. 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 14 1/26/2010 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 Membrane Transporters Fig. 5-9: Transport proteins of the cell membrane 15 1/26/2010 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 Transporter Proteins: Transporter Channels – Open & Gated Figure 5-11: Gating of channel proteins 11: 16 ...
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