PHYSIO-s10_02 - 1/24/2010 BIOL 260: Human Physiology Human...

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Unformatted text preview: 1/24/2010 BIOL 260: Human Physiology Human Spring 2010 M, Jan. 25, 2010 Spring Jan. Dr. Nathan Staples (Ph.D., UCSB 2002) Dr. (Ph.D., www.smccd.edu/accounts/staplesn/biol260 1. Lecture slides will be posted during the previous Lecture evening before lecture. Print WISELY if you choose to print (multiple pages/sheet, double-sided). (multiple 2. Pre-Lab Writeups: Be sure to prepare before each Lab W riteups Be before each Monday pr Wednesday labs (for WHOLE week!)!! Monday pr Wednesday – (What? Why? How? are we doing in the lab??) 3. This Week: Graphing practice, & Lab Exercises 1 & 2. Graphing 4. Handouts for NEW EXPERMENT 4!! Handouts • Available this WEDNESDAY!!!! (for next week’s lab) REVIEW 1. Describe and compare the teleologic and mechanistic views of physiology. Describe teleologic and mechanistic TODAY’s Objectives: Students should be able to…. 1. Citing examples, explain the importance of structure-ffunction relationships Citing structure unction and homeostasis in physiology/biology. and 2. Describe 5 types of intercellular communication. Describe types of intercellular 3. Describe and give an example of each of the 5 steps of a cellular signal Describe steps of pathway. pathway 4. Describe how cellular receptors and intercellular signals modulate/regulate Describe cellular and intercellular modulate/regulate responses to stimuli. (how do cells respond differently to the same signal?) responses 5. Describe Cannon’s postulates on the parameters and maintenance of postulates homeostatic/ homeodynamic systems. homeodynamic 1 1/24/2010 1.5) Themes in Physiology 1. Homeostasis 2. Structure/function Structure/function relationships relationships 3. Integration of systems 4. Communication 5. Membranes & exchange 6. Energy 7. Mass balance 8. Mass flow & resistance Figure 5-1: Mass balance in the body 1.6) Representing Data: Graphs • X- axis – Independent variable • Manipulated or set • Y- axis – Dependent variable • Measured • Line graph • Bar graph • Histogram • Scatter plot • Interpolation • "Best Fit" line Figure 1-7 2 1/24/2010 Representing Data Graphs: Line and Interpolation 1. Line: continuous continuous data along Z data 2. Bar Graph: distinct distinct sets of data sets • Histogram: Histogram: distribution of one variable over a range. range. Figure 1-7d Chapter 6 Communication, Integration, & Communication, Homeostasis Homeostasis 1. 2. 3. 4. 5. 6. 7. How cells communicate Electrical and chemical signals Receptor types and how they Receptor function function Local regulation of cells Modification of receptors and Modification signals signals Homeostatic balance depends Homeostatic on communication on Feedback regulates integration Feedback of systems of 3 1/24/2010 Cell Membrane (review Ch.3) 1. Barrier from Barrier a) Outside a) b) ECF 2. Cell gateway 3. Cell structure 4. Phospholipid bilayer Cell Membrane Figure 3-4: The cell membrane 4 1/24/2010 6.1) Overview of Cell to Cell 6.1) Communication: Communication: 1. Chemical a) Autocrine & Paracrine: local signaling Paracrine b) Endocrine system: distant, diffuse to target distant, (slow) (slow) 2. Electrical a) Gap junction: local b) Nervous system: fast, specific, distant target A. Gap Junctions and CAMs A. CAMs • Protein channels – connexin Protein connexons form form Gap Junctions Gap • Direct flow to adjacent Direct neighbor neighbor – Electrical- ions (charge) – Signal chemicals • CAMs = Cellular Adhesion Cellular Molecules Molecules – Need direct surface contact Need direct – Signal chemical Figure 6-1a, b: Direct and local cell -to-cell communication 5 1/24/2010 B. Paracrines and Autocrines B. Paracrines and Autocrines • Local communication • Signal chemicals Signal diffuse to target diffuse • Example: Cytokines – Autocrine – receptor on receptor same cell that secreted same – Paracrine – receptor on receptor neighboring/adjac. cells neighboring/ Figure 6-1c: Direct and local cell-to-cell cell communication communication C. Long Distance Communication: Long 1) Hormones 1) 1. Signal Chemicals 2. Made in Made endocrine cells endocrine 3. Transported via Transported blood blood 4. Receptors on Receptors target cells **** target Figure 6-2a: Long distance cell-to-cell cell communication communication 6 1/24/2010 Long Distance Communication: Long 2) Neurons and Neurohormones Neurohormones 1. Neurons – Electrical signal down axon – Signal molecule crosses gap Signal (neurotransmitter) to target cell • Common nerve-nerve, nervemuscle sense/response muscle pathways pathways 2. Neurohormones – Chemical and electrical Chemical signals down axon signals – Hormone transported via Hormone blood to target blood • Eg: breast milk release; breast nipple stimulation oxytocin release Figure 6-2 b, c: Long distance cellto-cell communication 6.2) Signal Pathways** 1. Signal molecule Signal (ligand) 2. Receptor 3. Intracellular signal 4. Target protein 5. Response Figure 6-3: Signal pathways 7 1/24/2010 A. Receptors: Locations 1. Cytosolic or Nuclear – Lipophilic ligand enters cell • (hydrophobic) Figure 6-4: Target cell receptors – Often activates gene – Slower response Slower 2. Cell membrane 2. – Lipophobic ligand can't enter cell • (hydrophilic) – Outer surface receptor – Fast response Membrane Receptor Classes (4) Receptor Channel Signal Signal Transduction!! T ransduction!! Figure 6-5: Four classes of membrane receptors 8 1/24/2010 B. Signal Transduction 1. Transforms signal Transforms energy & carries across membrane!!! across 2. Protein kinase Protein kinase – Phosphorylates other proteins – Transfers phosphate from ATP 3. Second messenger – NO, Ca++, CO 4. Activate proteins – Phosporylation – Bind calcium 5. Cell response Figure 6-8: Biological signal transduction 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 9 1/24/2010 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 1. GPCR: Adenylyl Cyclase-cAMP 1. Adenylyl The G proteincoupled coupled adenylyl adenylyl cyclase-cAMP system system Figure 6-11 10 1/24/2010 2. GPCR: The Phospholipase C System The Phospholipase Figure 6-12 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 11 1/24/2010 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 Modulation by Receptors Figure 6-18: Target response depends on the target receptor 12 1/24/2010 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 Tonic vs. Antagonistic Control • NOT just ON or OFF! Figure 6-20: Tonic control 20: 13 1/24/2010 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 Control Pathways Figure 6-22: Comparison of local and reflex control 14 1/24/2010 B. Reflex Control Feedback loop STIMULUS 1. Stimulus 2. Sensory receptor 3. Afferent path 4. Integration center 5. Efferent path 6. Effector- target cell/tissue 7. Response (feedback loop) Figure 6-23: Steps of a reflex pathway SENSOR or RECEPTOR AFFERENT PATHWAY Response loop INTEGRATING CENTER EFFERENT PATHWAY TARGET or EFFECTOR RESPONSE Types of Receptors: Types Membrane, CNS & Peripheral Membrane, Figure 6-24: Multiple meanings of the word receptor 15 1/24/2010 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 s etpoint 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 16 ...
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