Phys Winter #1.txt

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Phys Winter #1.txt
2010-12-31 13:57:33
Phys Winter

Physiology winter test #1
Show Answers:

  1. How many body systems are in the human body?
  2. What are the three things a body must do to maintain homeostasis? DIR
    • Detect
    • Integrate
    • restore
  3. What are the three parts of negative control? SIE
    • Sensor - recognizes signal
    • Integrate - interprets signal/instructs
    • Effector - communicates
  4. How does positive feedback work?
    It increases the signal (e.g. oxytocin and increasing contractions)
  5. What are the two components of ECF?
    • Plasma
    • Interstitial fluid
  6. Where are K+, Na+, Cl- and proteins highest in a cellular environment?
    • Na+= outside of cell (ECF)
    • K+= inside of cell (ICF)
    • Cl-= outside of cell (ECF)
    • Proteins = inside of cell (ICF)
  7. How does Osmosis work?
    • Water moves from area of low solute concentration to high solute concentration.
    • Works only in areas of impermeable solutes.
  8. What does Fick's Law state? (3 things)
    • Water/solute conc. equal
    • No more net movement
    • No volume change
  9. What is effective osmotic pressure?
    • Non-permeable solutes
    • Amount of pressure that finally stops diffusion of water
  10. What is the homeostatic osmolarity of intracellular/extracellular fluid?
    300 mOsm/L
  11. What is the formula for osmolarity?
    • #osmoles/Liter
    • osmoles = # of particles that will dissociate in solution
  12. Definition of Tonicity?
    the effect a solution has on the volume of the cell (hypoosmolar = swell, hyperosmolar = shrink, isoosmolar = steady state)
  13. What ion channels open up inside of a cell due to a hypoosmotic ECF?
    K+ and Cl-
  14. What two ion channels open up in response to a hyperosmotic solution?
    -Na+/H+ to bring Sodium in (H+ leaving causes the cell to become basic)

    -Cl-/HCO3- exchanger (no bicarb needed to cause cell to be basic, so it leaves)
  15. What is the main reason b/t facilitated diffusion and active transport?
    Active Transport requires ATP-energy
  16. What is the drug that inhibits the Na+/K+ATP-ase?
    Digitalis a.k.a. ouabain (cardiac glycosides)
  17. What does the sodium potassium ATP-ase pump?
    • 3 Sodium out
    • 2 Potassium in
  18. What pump is an example of a secondary active transporter?
    Na+/glucose (utilizes the ATP from the Na+/K+ ATP-ase for its energy gradient to bring glucose against its concentration gradient into the cell)
  19. What is the body water count? 60-40-20
    • 60 L total
    • 40 L ICF
    • 20 L ECF (3/4 interstitial, 1/4 Plasma)
  20. What is the formula for Total body water?
    TBW = .7LBM + .1 AT
  21. What is the fat to water rule?
    The more fat the less water
  22. What is the formula for osmolality?
    2Na+ + Glucose/18 + BUN/2.8
  23. What is the difference in membrane potential inside/outside of a cell?
    • Inside = negative
    • Outside = positive
  24. Is it easier for Potassium or Sodium to pass through a cell?
    Potassium due to more channels
  25. What is the equilibrium potential for Potassium?
    Ek= -90 mV
  26. What is the equilibrium potential for sodium?
    ENa+= +65mV
  27. What is the equilibrium potential for Chlorine?
    Ecl-= -90mV
  28. What is the equilibrium potential for Ca2+?
    ECa2+= +120mV
  29. What is the Nerst Equation and what does it calculate?
    Eion= (60/z) log (ionout/ionin)

    ***used to calculate equilibrium potential
  30. Does conductance (g) count on K or Na more?
    More on K
  31. Does a cell hyperpolarize or depolarize during states of hypokalemia?
    Hyperpolarize because RMP becomes more negative as well as the equilibrium potential becoming more negative
  32. What is Ohm's law and what does it calculate?
    • Em= (gkEk + gNaENa)/(gk+gNa)
    • ***shows resting membrane potential
  33. What are the two types of gated potential channels?
    • 1) ligand-gated
    • 2) mechanosensitive
  34. What is the one type of action potential channel?
  35. Are gated potentials uni- or bi-directional?
  36. What is the difference b/t activation of gated and action potentials?
    Gated change depending on magnitude of stimulus while action are all-or-nothing
  37. What happens to a current during a gated potential moment?
    It diminishes as it spreads from the center of activation
  38. Is an action potential bi- or uni-directional?
    Unidirectional and it does not dissipate throughout the neuron
  39. What size of neuron allows faster propogation of an action potential?
    Larger diameter (myelin will increase it as well)
  40. What is important about the axon hillock?
    Highest concentration of voltage gated channels for action potentials. Must reach threshhold around -60 to -65 before propogating.
  41. What is the resting membrane potential of a normal cell?
    -70 mV
  42. What are the two drugs that inhibit Na+ channels? (TL)
    • Tetrodotoxin
    • Lidocain
  43. What channel opens to restore a cell to homeostasis?
    Na+/K+ ATP-ase
  44. What is the differnce b/t contiguous and saltatory conduction?
    • Contiguous: no myelination so potential continues along every fiber
    • Saltatory: Jumping from myelin over nodes of Ranvier (faster)
  45. What is the disease where a person loses myelination of neuronal fibers?
    Multiple sclerosis
  46. What happens to a person with high free Calcium?
    • The calcium binds to the phospholipids and makes the threshhold potential more positive, therefore, requiring a stronger stimulus to reach threshhold
    • muscle weakness
  47. What happens to a person with low free calcium?
    • More easily excitable b/c cells are more negative
    • muscle twitching
  48. What is the affect of increased phosphate?
    • Phosphate binds to Calcium and causes a more easily excitable neuron
    • hypoparathyroidism
  49. What is the effect of decreased phosphate?
    • More free calcium b/c less bound to phosphate = less excitable neurons
    • hyperparathyroidism
  50. What happens to calcium during states of acidemia?
    More hydrogen which leads to more free calcium b/c of competition with binding to negative proteins = less excitable = muscle weakness
  51. What happens to calcium during alkalemia?
    Less hydrogen to compete for binding to proteins with calcium = less free calcium = more excitable = muscle twitching
  52. What forms the tunels of gap junctions (starts with C)?
  53. What type of synapse occurs in gap junctions, electrical or chemical?
    Electrical (continuous)
  54. What is faster, an electrical or chemical synapse?
  55. What ion channel is necessary to insert neurotransmitter into synaptic vesicles?
    H+ channels
  56. What ion channel must open to bind synaptic vesicles to postsynaptic cleft?
    Ca2+ channels
  57. What are the three methods of neurotransmitter termination?
    • 1) degradation by AchEsterase
    • 2) Reuptake by presynaptic cleft
    • 3) diffusion
  58. Is an End Plate Potential a graded or action potential?
  59. What is the protein that senses increased Ca2+ in the presynaptic terminal and helps initiate binding?
  60. What is Lambert-Eaton syndrome?
    Disease that inactivates presynaptic Ca2+ channels so no binding of synaptic vesicles or clear vesicles can occur
  61. What do dense-core vesicles contain?
    Neuropeptide (not neurotransmitter)
  62. What are ionotropic and metabotropic receptors?
    • Ionotropic: ion channels on postsynaptic cleft
    • Metabotropic: G-protein channels
  63. What are the two main effects of cocaine on synapses?
    • Block dopamine reuptake
    • Block Sodium channels
  64. What is the difference between a sarcolemma and a motor end plate? (What kind of channels)
    • Sarcolemma: voltage-gated
    • Motor end plate: chemically-gated
  65. How many Ach must bind to the MEP to open the Na/K channel?
  66. What pump is activated to bring Ach into the synaptic vesicle?
    Hydrogen pump so the H/Ach pump can function with a gradient
  67. What is the function of Tubocurarine (curare)?
    Competitive antagonist against Acb
  68. What is the function of Succinylcholine?
    mimic Ach so muscle is depolarized too much and eventually paralyzed
  69. What is the effect of botulism toxin?
    • Botulism taken up by pre-synaptic cleft
    • blocks snare proteins so vesicle does not bind
    • no depolarization = muscle weakness
  70. What is the effect of AchEsterase poisoning?
    • no Ach degredation
    • muscle twitching, followed by flaccid muscles
  71. How does Myasthenia gravis function?
    • antibodies against Ach receptors
    • to cure, treat with Achesterase inhibitors so more Ach can compete with the blocking antibodies
  72. What is the function of neostigmine?
    Reversible AchEsterase inhibitor (used for MG and after surgeries to recover from muscle relaxants)
  73. Where are the DHP and RYR receptors located?
    • DHP: t-tubule
    • RYR: Sarcoplasmic Reticulum
  74. How does the DHP/RYR system work?
    DHP mechanically opens RYR
  75. What is the function of tropomyosin?
    inhibit binding of myosin to thin actin filaments
  76. What is the function of Troponin and what are its three partrs?
    • ***Calcium sensor
    • TnT: ties together Troponin and Tropomyosin
    • Tnl: bound to actin and inhibits ATPase activity
    • TnC: senses and binds Calcium
  77. What is the function of Titin and nebulin?
    • Titin: ties thick myosin filaments to z-band
    • Nebulin: controls length of thin actin filaments
  78. What is the function of Dystrophin?
    bind actin filaments to sarcolemma cytoskeleton
  79. What disease occurs if there is a lessening of Dystrophin?
    Muscular Dystrophy = muscle weakness b/c no link for contraction to occur
  80. Where is casequestrin found and what is its function?
    • RYR
    • function: sequester calcium and store it for release, reduces free calcium so excitation can occur
  81. What is the process of recruitment?
    • Utilizing various different motor units to activate movement
    • Is good for modulating and maintaining muscle strength
  82. What is the difference b/t type I and II muscle fibers?
    • I : slow, aerobic, endurance
    • II : fast, anaerobic, sprint
  83. What are the three ways that muscles can grow or shrink?
    • Neuronal
    • Muscle hypertrophy
    • muscle fiber change
  84. Does muscle hypertrophy deal with # or size?
    Just size, the number of fibers never changes
  85. When is neuronal change largest, early or late training?
    Early training
  86. Why is myostatin important?
    If absent, muscle hypertrophy still continues but the tendons are very weak and brittle
  87. What is sarcopenia?
    loss of skeletal muscle mass and strength due to aging
  88. When a spinal injury occurs, what type of fiber type will increase in the body?
    Type IIx
  89. What are the three functions of smooth muscles?
    • motility
    • pressure
    • flow
  90. What are the two types of smooth muscle?
    • Single-unit
    • multi-unit
  91. What do smooth muscles have in place of MEP?
  92. What smooth muscle type contains gap junctions?
  93. Which smooth muscle is myogenic and neurogenic?
    • Myogenic = single unit = self-excitable with no required neuronal signalling
    • Neurogenic = multi-unit = fine control, requires neuronal signalling
  94. Which smooth muscle type fires action potentials?
  95. What hormones are released by the sympathetic pathway?
    • 1) Epinephrine 80%
    • 2) Norepinephrine 20%
    • 3) Dopamine
    • ***all from adrenal medulla
    • ***parasym does not release hormones
  96. What is the one exception to the post-ganglionic axons in sympathetics?
    Sweat Glands: Cholinergic instead of adrenergic
  97. What are three areas of cooperation b/t the sym and parasym pathways?
    • 1) salivary glands: s = thick,p = watery
    • 2) lacrimal: both produce tears
    • 3) Sexual: p = erection, s = ejaculation
  98. What are three methods of bringing Calcium into SM for contraction?
    • 1) Voltage-gated: ECF
    • 2) Ligand-gated: ECF
    • 3) IP3: SR
  99. What are the three methods of removing Calcium from smooth muscles?
    • 1) SR Ca-ATPase
    • 2) Sarcolemma Na/Ca Exchanger
    • 3) Sarcolemma Ca-ATPase