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47 Cards in this Set
- Front
- Back
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Sensor |
Measures controlled variable |
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Integrator |
Compares sensor info with set point |
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Error signal |
Output of integrator that controls effector |
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Effector |
Mechanism that ultimately adjusts controlled variable |
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High gain |
Maintains small error - most common |
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Low gain |
Maintains significant error |
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Time lag - short and long |
short - quick response long - long response |
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In a perfect controlled system |
Infinite gain and zero time lag Reality - NOT the case, finite gain and response time |
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Open Loop Feedback |
System normally under negative feedback is disrupted - no + or - feedback Ex - ParkinsonAlso happens normally in rapid systems - to overcome time lag inherent to control system (rapid piano playing, rapid typing) |
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Phospholipid (PL) Structure |
Glycerol (3-C) 2 fatty acids (long hydrocarbon) Phosphate group |
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Saturated fatty acid |
c-c single bonds, higher freezing temp |
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Unsaturated fatty acid |
C=C double bond (at least one) kinks dec freezing temperature |
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Amphipathic |
Part of the molecule polar (hydrophilic), part of the molecule non polar (hydrophobic)
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Bilayer membrane |
- Very thin, remarkably stable - Membrane lipids are fluid - lateral diffusion but DO NOT flip from one side to the other - Lipids provide a barrier for for trans-membrane flow of POLAR substance - NO barrier to flow of NON-POLAR substance |
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Total Body Fluid - ECF / ICF |
3 compartments ECF 2 compartments Plasma - circulating in the blood ISF - around body cells |
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Compartments of Body Fluids ECF vs ICF NaKCaClHCO2 |
Na+ 140|10 K+ 4|150 Ca++ 5|3 Cl- 105|2 HCO2- 25|-- |
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IMPORTANT Distinction with Ca++ |
5 ECF vs 3 ICF - total concentrations, not diffusible amount ECF: 50% bound to proteins actual concentration 2.5mM ICF: >99.9% bound - 0.0001mM |
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FORMULA Measurement of Volumes |
Vol = Amount added - amount excreted / concentration in sample Amount excreted = [Urine]xUrine Volume |
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Indicators for measuring TBW |
D2O, antipyrine |
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Indicators for measuring ECF |
Inulin, mannitol
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Indicators for measuring TBV |
Radioactive RBCs
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Indicators for measuring Plasma |
Radioactive albumin, Evan's Blue |
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FORMULA ICF = |
ICF = TBW - ECF |
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FORMULA ISF = |
ISF = ECF - Plasma |
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FORMULA VBlood = |
VBlood = Vplasma + VRBC Vblood = Vplasma / 1 - Hct |
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FORMULA Einstein Relationship |
x = distance (cm) D = diffusion constant (cm2/s) t = time Large molecule = small D Small molecule D = 10^-5 |
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Bulk Flow |
Used for rapid transport over long distances - relies on pressure difference - Hydrostatic pressure: heart - Pneumatic pressure: in lungs |
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FORMULA Net Flow |
Flownet = AP(C1-C2) C1>C2 solute accumulates in the cell C12 solute leaves the cell C1=C2 zero net flow Net flow = 0 can still have unidirectional flow - driving force = concentration difference |
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Simple Diffusion |
NEVER have uphill flow, net flow ALWAYS down a concentration gradient |
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FORMULA Permeability |
Small molecule - Higher P, also higher D Hydrophobic = HIGHER Beta (partition coefficient) |
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Protein mediated transport - Facilitated diffusion |
- high selectivity only transports a certain solute - used to transport polar substances - mediated by protein carriers - bind a solute, undergo conformational change, release on the other side of the membrane - Saturable kinetics, can exhibit competitive inhibition - NO UPHILL |
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Primary Active Transport |
- All of the characteristics of facilitatedBUT can move from low -> high concentration "UPHILL" - Mediated by altering solute binding affinity of carrier - Requires energy - ATP |
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Na+,K+-ATPase - Sodium Pump |
Example of PAT 3 Na+ out of cell, 2 K+ into cell Uses 1 ATP molecule Need to maintain cell volume |
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Ouabain / digitalis / digoxin |
Cardiac-glycoside drug, inhibits the sodium pump |
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Other Primary Active Transport Examples |
Calcium pump, proton pump, H+/K+ exchange pumps |
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Secondary Active Transport |
- All of the characteristics of facilitated BUT can move from low -> high concentration "UPHILL" - Dependent on Na+ gradient - Cotransporters |
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H2O Transport |
- Mediated via osmosis - NO primary active transport - Moves via osmosis - high -> low concentration |
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Solutes in Solution |
Solutes take up space, dec water concentration 1 M glucose = sucrose = AA 1 M glucose = 0.5 NaCl = 1/3 CaCl2 |
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Hyperosmotic |
Hyperosmotic bath > cell |
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Isosmotic |
Isosmotic bath = cell |
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Hypo-osmotic |
Hypo-osmotic bath < cell |
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Immediate Response Look at |
OSMOLARITY - chemical property Hyperosmotic - shrinks Isosmotic - no change Hypo-osmotic - cell swells |
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Tonicity |
What happens when cell placed in solution |
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Hypertonic |
Cell shrinks |
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Isotonic |
No change
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Hypotonic |
Cell swells |
