1 / 33

Foreword

Foreword.  In the course of three months - our staff will guide you through the secrets of Me- - dical Biophysics Both lectures , and practicals are obligatory for students.  You will attend Lectures and Practicals according to timetable (your questions

jregina
Télécharger la présentation

Foreword

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Foreword  In the course of three months - our staff will guide you through the secrets of Me- - dical Biophysics Both lectures, and practicals are obligatory for students.  You will attend Lectures and Practicals according to timetable (your questions e.g. how to get credit, substitution in the case of illness, etc. are discussed with teachers during Practical sessions ) For Instructions to organization of study and details ask following teachers: Prof. Jakuš - head, Dr. Simera-vicehead Dr Poliacek-Assoc.Prof

  2. Content of study Coversfollowingtopics.:BiophysicsofCell, Transport membranemechanisms, Resting and Actionpotentials , Musclecontraction, Synapse, Basicsofrespiration, Heart and circulatorysys-ems, Senses, Hearing, Vision. Changes in body due to actionofmechanicalanelectromagneticinfluences, EffectsofSound, Infrared and Ultravio-letradiations, Radioactivity, Diagnosticmethods in humanmedicine: X-ray, Utrasound, Computertomography, Magnetictomography, etc. Therapy in humanmedicine, Biocybernetics, ModernMachines, Nanotechnology and manyothers. For more detailslookfor my Lecturesbeingavailable to see and downloadfromourfacultyhomepage: www.jfmed.uniba.sk/index.php?id=3649

  3. Study Literature - Source 1.Lectures– thecontentresultsfromProfessorsexperience, alsofromTextbookofMedicalBiophysics (in Slovak ), alsofromGanong´sTextbookofPhysiology ContentofsomeLectures and Practicals ,ProgrammeofLectures, Requirements and conditionhow to obtaincredits, pointsetc. are available on web.page: www.jfmed.uniba.sk/index.php?id=3649 2.Textbooks- Nave&Nave: PhysicsforHealth Sciences,1985, Ronto,Tarjanetal.:Anintroduction to BiophysicswithMedicalOrientation, 1999, 3. Booklet-Kukurovaetal.:BiophysicalElixir, 1991 4. WorksheetforPracticalsJakus,Poliacek, Simera :PracticalTasks in MedicalBiophysics ,2013 , itcontainstheory and personalprotocol to particulartasks.

  4. Medical Biophysics. Biophysics of a Cell. Transport membrane mechanisms. Resting membrane potential. LECTURE 1 JánJakuš (www.jfmed.uniba.sk/index.php?id=3649) Martin 2014

  5. Medical Biophysics is an interdisciplinary subject of medical scien-ces,explaining basic problems of a human body at a level of atoms, molecules, cells, tissues, and organs answers the physical problems that appear in biology, chemistry, anatomy, physiology... explains effects of radiation, giving rules and recommendations for their use and safety explains and creates new methods and devices for diagnosis and treatment of human diseases

  6. Medical Biophysics - kind of Medicine Science, a part of Biophysics

  7. HUMAN CELL Definition: Cellis a basicanatomical and functionalunitofthe body withtotalnumberof 60.000 bilions and sizefrom 4-120 µm (10-6 m). Numberofcellscomposestissues(206 bones ,600 muscles, thousandsofnerves), numberoftissuesbuildsorgans (heart, lungs, kidney.. ) Typicalsignsoflivingcell: ownmeta-bolism, excitability, reproduction Composition: Cytoskeleton -surfacemembrane,cytoplasm,organelles(fordetailsseeourvideosatPracticalSessionsalsolook a bookofBiology)

  8. SURFACE MEMBRANE

  9. Surface Membrane of RBC

  10. Surface Membrane (SM) Intracellular SM-coverssubcellularstructures(e.g.Nucleus, Golgicomplex, Mitochondria) Plasmatic SM - coversthesurfaceofeachcell Functions:semipermeability,division, protec-tion, integrativeroles, transport ofions, sourceofenzymes, storageofelectriccharges, etc. Composition: SM isPhospholipidbilayer- 45% Hydrophilicheads(consistingofphosphates-soluble in water) Hydrophobictails (consisitingofhydrocarbonfattyacids-insoluble in water- 45%) . Proteinsbilayer (peripheral, integral) - 50% , +Sugar + Cholesterol (5%) Headsare (+) electricallycharged and directedtowardsthemembraneexterior, tailsare chargednegatively (–), beingoriented to membraneinterior

  11. Transport Membrane Mechanisms areresponsibleformovementofwater and solutesacrossthecellmembrane areofvitalimportanceforcellmetabo-lism, forproductionofcellelectricityi.e. (resting and actionmembranepotentials) Types: PASSIVE - itdoesnotneeddeli-veryof a freeenergy. (Simple and Facilita-tedDiffusion, Osmosis, Filtration). ACTIVE - freeenergyfrom ATP isneeded and mustbedelivered(Na-Kpump, Ca-pump, H-pump, exo/ endo-cytosis, and phagocytosis)

  12. Simple Diffusion through cell membrane

  13. Simple Diffusion is a kind of passive membrane transport of H20, solutes, or gases (O2, CO2) from the space with a higher concentration towards the space with lower one (along the concentration gra-dient), untill the equilibrium is established. Total volume of solution does not change in both of spaces. Rate of diffusion:Fick Law: J = - d . conc.grad.[d- koeficient of diffusion] Generally: diffusion depends - linearlyon a conc. gradient, solubility of a matter, and on ambient temperatureNonlinearlydependson a size of particles Types of diffusion: Simple, Facilitated, Throu-gh the protein channels

  14. Scheme of Facilitated Diffusion

  15. Facilitated Diffusion is a passive transport mechanism of bigger molecules (e.g.aminoacids),along a concentration gradient, when substance binds to a protein carrier thecarrier is protein placed within the membrane and undergoes a process of conformation (is a change of its chemistry) afterbinding of moleculeand conformation, the carrier shifts (turns around ) and finally releases substance on an opposite site of a cell membrane

  16. Diffusion through the protein (ion selective) channels is a passive transport of ions Na+, K+, Ca2+, Cl- ,or low molecular soluble sub-stances through the protein channels within the membrane, along the concen-tration gradient Protein channels are :1.“voltage“gated - they are open or closed (gating) due to a membrane electricity,or 2.„ligand“gated-when e.g. a hormone binds to a channel, thus opening it.

  17. „Voltage“ and „ligand“ gated protein (ion selective) channels

  18. Filtration is a passive transport of water and small particles from a space with higher hyd-rostatic pressure to a space with lower one the power that drives Filtration is Pressure gradient of a hydrostatic pressure(not a concentration gradient ! ) examples: filtration and resorption in capillary loop or in kidneys

  19. Osmosis iskindofpassive transport throughthesemipermeablecellmembrane, whenonlywatermovesfrom a spacewithlowerconcentration (lowerosmoticpressure) to a spacewithhigherconcentration (higherosmoticpressure), till to equilibrium.Totalvolumeofsolution in bothcompartmentswillchange. Simply –waterwants to dilute more concentratedsolution(VanHoff´sLaw) normalosmolarity300 mOsm/l- isotonicsolutionwithbloodplasma (e.g. 0.9 % NaCl, or 5% ofglucose)Below 0.9%- hypotonicsolution Above 0.9% - hypertonicsolution example: Osmoticfragilityof RBC ( see practicals)

  20. OSMOSIS – scheme

  21. Changes in sizeof RBC due to osmosis(HAEMOLYSIS)

  22. ACTIVE MEMBRANE TRANSPORTS transport ofmoleculesamongcellsagainsttheconcentration, or electricgradients, a deliveryoffreeenergyfrom ATP iscrucial. Classification:Primaryactive transportthroughtheselectíveionschannels. Pumps : Na +- K+ pump (in allcells),Ca2+- pump (in musclecells), H+- protonpump (in cellsofstomachproducingHCl) Secondaryactive transport when a substance (e.g. glucose)binds on ion (Na+), thenthiscomplex (Na+glucose) iscarriedthroughthemembraneactively (theglucose-Na+contransport), exo-/endo, phagocytosis

  23. Na+-K+ pump (Na+- K+ ATPase)

  24. Na+- K+ pump – scheme

  25. Na+-K+ pump (Na+- K+- ATP-ase) - Itisanenzyme,placedwithinthecellmembrane (number =106 moleculeswithin a membraneofoneneuron) - itcarries3 ionsof Na+frominside to outside, and atthesametime, 2 K+fromoutside to insideofthecell • Itcanexchange max. 200 Na+ and 133 K+ / sec. (maximalcapacityofpump) - Itrequiresdeliveryoffreeenergy (from ATP) • Itisimportantforrenewalofelectriccharges on body cells

  26. Exocytosis, Endocytosis (Phagocytosis)

  27. ACTIVE membrane transports.: Exocytosis and Endocytosis.  Exocytosis - “cell vomiting“ is a release of larger molecules by the protrusion of a cellular membrane, under delivery of energy and Ca2+ ions Endocytosis –“cell eating“ is an uptake of molecules by a cellular membrane, e.g. ingestion of bacteria by leukocytes (phagocytosis). It needs a delivery of energy, too.

  28. Resting membrane potential (RMP) Itisanelectricpotentialdifferencemeasuredbetween (+) chargedcellexterior and (–) chargedcellinterior. Itsvalueisnegative and equals to a SumofEquilibriumPotentialsofall 3 ions (K+, Na+, Cl-). is a resultofmembranesemipermeabilityi.e. differentleakageofcellmembranefor 3 mainions (K+, Na+, Cl-). permeabilityofcellmembraneforionsatrestis: K+ : Na+ : Cl- = 1 : 0.04 : 0.45 K+ : Na+ : Cl- = 100 : 4 : 45 (%) Valueof RMP for nerve cellsis: -70 mV, sceletalmuscle:– 90 mV, heartmuscle:- 80mV, smoothmuscle: -50 mV (non-stabile)

  29. EquilibriumPotential(EP)is a valueofelectricalvoltagethat just stopsthepassivediffusionofions (K+ ,Na+ ,Cl-)alongtheirconcentrationgradientsCellInside (-) chargedCellOutside(+) cha.(because PROTEINS inside) (because Na +outside)

  30. Concentration and electrical gradients of K+, Na+, Cl- ionsOUTSIDE INSIDE

  31. Nernst formulaEach ion has its own Equilibrium Potential (mV) which can be counted: (Nernst counted it only for K+ )

  32. Goldman´sEquationSumationofallEquilibriumpotentials (for K, Na, Cl ) results in a realvalueofRestingMembranePotential ( e.g. V m= -70 mVforneuronalcells)Goldmanncounteditforall 3 ions (theirconcentrationsoutside and inside) +thepermeabilitiesofmembranefor 3 ions

  33. . for comming and attention

More Related