Phys Final

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Anonymous
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18034
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Phys Final
Updated:
2010-05-06 13:53:04
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Human Physiology
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Homeostasis
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  1. Functions of all tissues is
    Maintenance of a constant internal environment
  2. Intracellular fluid<->Intersticial fluid<->Plasma<->Organs<->External Environment
    Exchange and communication are key concepts for understanding physiological homeostasis
  3. Homeostasis refers to the dynamic mechanisms that
    Sense or detect deviations in physiological variables from their "set point" values bu initiating effector responses that restore the variables to the optimal range
  4. Exploring Homeostasis
    • Identify the internal environmental variable
    • Establish the "set point' value for that variable
    • Identify the inputs and outputs affecting the variable
    • Examine the balance between the inputs and outputs
    • Determine how the body monitors/senses the variable
    • Identify Effectors that restore variable to its set point
  5. How are homeostatic systems controlled?
    Reflex pathways
  6. Negative feedback
    An increase in a parameter causes changes that lead to a decreases in the value of the parameter, vice versa.
  7. Positive feedback
    An increase in a parameter that causes changes that lead to a further increase in the value of the parameter, vice versa.
  8. Homeostatic control systems require:
    Communication, networks utilizing signal molecules that bind to receptors
  9. Communication Signals
    Neural: signal crosses synapse to affect target cells
    Endocrine: signal reaches distant targets via blood transport
    Paracrine: signal reaches neighboring cells via ISF
    Autocrine: signal affects the cell that synthesized the signal
  10. Physiological Parameters
    Internal environment variable that is regulated so it remains within a "set point"
  11. Circadian rhythms add an aticipatory component to homeostasis
  12. Total body balance depends on:
    net gain vs net loss
  13. Metabolism:
    Catabolic breakdown: need energy sources and O2, produce CO2
    Anabolic synthesis: need precursors for nucleic acids, protiens, lipids and carbs
  14. Multicellular organisms
    Bulk transport; mvmnt of substances to/from cell surface to interface with external environment
    Communication: cells communicate in order to coordinate fxns
  15. Allosteric modulator
    forms non-covalent bond with protein
  16. Covalent modulator
    forms a covalent bond with the protein
  17. Law of mass action
    increase in the amount of reactants will increase the rate of production formation
  18. Glycolysis: oxidation of glucose
    • Net: 2 molecules of ATP synthesized 2 NAD+
    • Can occur anaerobically to form lactic acid
    • Not much energy captured
    • Oxidized NAD+ is regenerated
  19. Citric acid and electron transport chain
    • carries electrons to the ETC where they are transferred to O2 reducing it to H2O
    • Synthesizes ATP by capturing energy
    • Lots of energy captured
    • Acetate to 2CO2
  20. ATP provides energy to make a molecule more reactive
  21. Glycolysis
    • Aerobic conditions:
    • Glucose to pyruvate
    • Small ATP generated
    • NAD+ reduced to NADH
    • Anaerobic conditions
    • Glucose to lactate
    • NAD+ regenerated to maintain ATP production
  22. Diffusion due to random thermal motion
  23. Net flux
    accounts for solute movements in both directions
  24. Net movement
    toward the area of lesser concentration until dynamic equilibrium is reached
  25. Factors that affect diffusion
    • Magnitude of concentration gradient
    • Permeability of membrane
    • presence of transport or pore proteins
    • Surface area
    • Molecular mass
    • Distance
    • biological membranes tend to be thin
    • Temperature
  26. Hypertonic, Isotonic, Hypotonic
    • Hypertonic, cell shrinks, solution more concentrated
    • Hypotonic, cell swells, solution more dilute
  27. Protein ion channels
    • transmembrane proteins that form aqueous pores
    • carry ions through lipid membranes down their electrochemical gradient
  28. Carrier-mediated transport
    • transmembrane protiens
    • transport ions and other solutes down or against their gradients
  29. Active transport
    solute moved against its concentration gradient
  30. ATP hydrolysis changes protein conformation
  31. Secondary active transport
    • solute is glucose, amino acid, or another ion
    • binding changes protein conformation and affinity for solute
  32. Secondary active transport
    Symport
    Antiport
  33. primary active transport ATPases
    •H+ ATPase found on inner mitochondrial membrane –involved in ATP synthesis



    • •H+ / K+ ATPase
    • found in stomach and kidney



    • •Ca2+ ATPase:
    • –Found in plasma membrane, where

    • it pumps Ca2+ out of the cytosol into the ECF
    • –Found in the membrane of smooth

    • ER, where it pumps Ca2+ into the lumen of the
    • ER
  34. Epithelial Transport
    • often asymmetrical:
    • Net transport can occur in one direction across the epithelial sheet or tube
  35. Intracellular Signal Transduction
    • 
    • •Lipid soluble (nonpolar)
    • messengers


    • –Cytosolic
    • (intracellular) receptors


    • •Water soluble (polar)
    • messengers


    • –Kinase
    • receptors


    –G protein coupled receptors


    •Cyclic nucleotides (via nucleotide cyclases)


    •Cytosolic Ca2+ (via phospholipase C)



    • •Arachidonic
    • acid derivatives (via phospholipase A2)
  36. Lipid-soluble messengers act as regulators of transcription factors
  37. G-protein coupled signal transduction
    This is a GTPase enzyme, active when GTP is bound, inactive when GDP is bound
  38. Adenylate Cyclase enzyme: cyclic AMP formation and PKA activation
    • PKA is activated by cAMP, relative activity of AC and PDE enzymes controls [cAMP]
    • Adenylate cyclase catalyzes the formation of cAMP
    • Phosphodiesterase inactivates cAMP
  39. One type of second-messenger enzyme can coordinate many cell processes via target protiens
  40. PKC is avtivated by calcium release form the ER and DAG in plasma membrane
    • PLC hydrolyzes mbn lipid (PIP2) to form IP3 (water soluble) and DAG (lipid soluble)
    • PKC requires both calcium and DAG for activation
  41. Arachidonic Acid signaling initiated by:
    • Phospholipase A2-these lipids are important in paracrine signaling
    • COX enzyme inhibited by ibuprofen eg.
  42. Antagonist: competes for a receptor with a chemical messenger normally in body
    Agonist: A chemical messenger binds to receptor and triggers cells response
    Down-regulation: decrease in total number of target-cell receptors for a given messenger
    Up-regulation: increase in total number of target-cell receptor for a given messenger
  43. Electrical potentials result from:
    separation of charged particles
  44. Charge separation across membrane is small fraction of total number of particles
  45. Na+ Inward
    K+ Outward
  46. Steady state:
    net ion flux due to diffusion is exactly balanced by active transport of ions by the pump NOT EQUILIBRIUM
  47. Nervous system: rapid control of processes in the organism (behavior)
    • Composed of neurons and other cellular elements
    • sensory systems
    • integrative systems
    • motor systems
  48. Anterograde transport: away from cell body: kinesin
    Retrograde transport: toward cell body: dynein
  49. CNS Cell types
    neurons
    astrocytes: form blood brain barrier
    oligodendrocytes: form myelin sheaths
    microglia: brain macrophages
  50. Afferent neurons and efferent neurons are in the __________ nervous sytem. Over 99 percent of neurons are ____________.
    PNS Interneurons
  51. Presynaptic: Sender
    Postsynaptic: receiver
  52. Transient changes
    2 types: graded potentials (transduction and integration)
    action potentials (transmission)
    mediates information processing and trasmission by nerve cells
  53. The opening and closing of ion channels results from changes in integral proteins due to:
    membrane potential changes or ligand binding
  54. Repolarization of the action potential is due to:
    Action potential is "all or none"
    • rapid inactivation of depolarization-activated sodium channels
    • slower activation of depolarization-activated potassium channels
  55. Sodium channels are located:
    only at modes (active sites)
  56. What is lost in MS?
    Myelin sheath which leads to slowing or failure of AP conduction
  57. B-cell receptor
    Immunoglobulin on plasma membrane surface
  58. T-cell receptor
    Immunoglobulin-like molecule on plasma membrane surface. Interacts with specific antigen only when it is "complexed with an MHC molecule
  59. Major Hitocompatibility Complex (MHC)
    • gene cluster code for proteins found at cell surface
    • Everyone has a unique set of MHC genes and proteings
    • MHC serves as "self' identiy tags
  60. Helper T cells only interact with antigen encountered on macrophages, dendritic cells & B cells since they express Class II MHC protiens
  61. Acquired Immune Response
    • Extracellular pathogen
    • Microbe-infected cells or cancer cells
  62. How does your immune system lear to distinguish the bodies' own molecules form foreign ones?
    During fetal and early post-natal life, T and B cells that recognize "self" molecules are eliminated in th thymus (colonal deletion) or inactivated in the periphery (colonal inactivation)
  63. Immune surveillance
    process where body (self) recognizes itself as distinct forn foreign molecules
  64. Cellular Components
    Neutrophils: blood-born phagocyte eat foreign matter
    Monocytes: macrophage precursors in blood
    Macrophages: tissue dwelling phagocytes
    Dendritic cells: (macrophage-like cells)
    Lyphocytes:
    Mast Cells: reside in tissue; mediate allergic responses
  65. Cytokines
    • Protein messengers released by immune cells and other tissue cells
    • Function as both paracrine/autocrine and endocrine signals
    • IL-1 & TNFa: initiates inflammatory response adn mediate sickness response
  66. Innate (nonspecific) response
    • Phagocytes have receptors that recognize classes of foreign molecules
    • Injury or infection cause chemotaxis- attraction of immune cells to the site
  67. Acquired immune response
    • mediated by lymphocyte makes a receptor that recognizes a specific foreign molecule or antigen
    • All of the progeny of each lymphocyte are called clones
    • recognition of antigen results in clonal expansion-proliferation of specific lymphocyte
    • Effecor cells-carry out attack
    • Memory cells-for future encounters with antigen
  68. Primary and secondary lyphoid organs
    • Primary-bone marrow and thymus
    • Secondary-lymph nodes, spleen, tonsils and adenoids
  69. Humoral (antibody-mediated) response
    • B lymphocytes produce immunoglobulin molecules that recognize a specific antigen (secreted as antibodies)
    • Antibody (AB) functions: attachment to antigen can directly inactivate it, attachment to antigen enhances phagocytosis (opsinization)

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