Downloaded 109 times
More Related Content
Similar to Bioelectricity& Excitable Tissue
Bioelectricity& Excitable Tissue
- 1. BIOELECTRICITY AND EXCITABLETISSUE THE ORIGIN OF BIOELECTRICITY AND HOW NERVES WORK www.freelivedoctor.com
- 2. THE RESTING CELLHIGH POTASSIUM LOW SODIUM NA/K ATPASE PUMP RESTING POTENTIAL ABOUT 90 - 120 MV OSMOTICALLY BALANCED (CONSTANT VOLUME) www.freelivedoctor.com
- 3.
- 4. BIOELECTRICITY THE ORIGINOF THE MEMBRANE POTENTIAL www.freelivedoctor.com
- 5. MOBILITY OF IONSDEPENDS ON HYDRATED SIZE IONS WITH SMALLER CRYSTAL RADIUS HAVE A HIGHER CHARGE DENSITY THE HIGHER CHARGE DENSITY ATTRACTS MORE WATER OF HYDRATION THUS THE SMALLER THE CRYSTAL RADIUS, THE LOWER THE MOBILITY IN WATER www.freelivedoctor.com
- 6. IONS MOVE WITHTHEIR HYDRATION SHELLS - + - + Hydration Shells - + - + - + - + - + - + - + - + - + www.freelivedoctor.com Na + - + - + Cl - - + - + - + - + - + - + - + - + - + - + - + - + - +
- 7. ELECTRONEUTRAL DIFFUSSION HIGHSALT CONCEMTRATION LOW SALT CONCEMTRATION BARRIER SEPARATES THE TWO SOLUTIONS www.freelivedoctor.com + - + - + - + - + - + - + - + -
- 8. ELECTRONEUTRAL DIFFUSSION +- CHARGE SEPARATION = ELECTRICAL POTENTIAL www.freelivedoctor.com HIGH SALT CONCEMTRATION LOW SALT CONCEMTRATION + - BARRIER REMOVED + - + - + - + - + - + - + -
- 9. ELECTRICAL POTENTIAL=CHARGE SEPARATIONIn water, without a membrane hydrated Chloride is smaller than hydrated Sodium, therefore faster: Cl - Na + The resulting separation of charge is called an ELECTRICAL POTENTIAL + - www.freelivedoctor.com
- 10. THE MEMBRANE POTENTIALM E M B R A N E Extracellular Fluid Intracellular Fluid Na + K + Sodium channel is less open causing sodium to be slower Potassium channel is more open causing potassium to be faster + - MEMRANE POTENTIAL (ABOUT 90 -120 mv) www.freelivedoctor.com
- 11. THE ORIGIN OFBIOELECTRICITY POTASSIUM CHANNELS ALLOW HIGH MOBILITY SODIUM CHANNELS LESS OPEN CHARGE SEPARATION OCCURS UNTIL BOTH MOVE AT SAME SPEED STEADY STEADY IS ACHIEVED WITH A CONSTANT MEMBRANE POTENTIAL www.freelivedoctor.com
- 12. THE RESTING CELLHIGH POTASSIUM LOW SODIUM NA/K ATPASE PUMP RESTING POTENTIAL ABOUT 90 - 120 MV OSMOTICALLY BALANCED (CONSTANT VOLUME) www.freelivedoctor.com
- 13.
- 14. ACTIVE TRANSPORT ADP ATP www.freelivedoctor.com
- 15. ACTIVE TRANSPORT REQUIRESAN INPUT OF ENERGY USUALLY IN THE FORM OF ATP ATPase IS INVOLVED SOME ASYMMETRY IS NECESSARY CAN PUMP UPHILL www.freelivedoctor.com
- 16. EXCITABLE TISSUES NERVEAND MUSCLE VOLTAGE GATED CHANNELS DEPOLARIZATION LESS THAN THRESHOLD IS GRADED DEPOLARIZATION BEYOND THRESHOLD LEADS TO ACTION POTENTIAL ACTION POTENTIAL IS ALL OR NONE www.freelivedoctor.com
- 17. THE NERVE CELLCELL BODY DENDRITES AXON AXON HILLOCK AXON TERMINALS www.freelivedoctor.com
- 18. EXCITABLE TISSUES:THE ACTIONPOTENTIAL THE MEMBRANE USES VOLTAGE GATED CHANNELS TO SWITCH FROM A POTASSIUM DOMINATED TO A SODIUM DOMINATED POTENTIAL IT THEN INACTIVATES AND RETURNS TO THE RESTING STATE THE RESPONSE IS “ALL OR NONE” www.freelivedoctor.com
- 19. EQUILIBRIUM POTENTIALS FORIONS FOR EACH CONCENTRATION DIFFERENCE ACROSS THE MEMBRANE THERE IS AN ELECTRIC POTENTIAL DIFFERENCE WHICH WILL PRODUCE EQUILIBRIUM. AT EQUILIBRIUM NO NET ION FLOW OCCURS www.freelivedoctor.com
- 20. THE EQUILIBRIUM MEMBRANEPOTENTIAL FOR POTASSIUM IS -90 mV + - CONCENTRATION POTENTIAL K + K + IN www.freelivedoctor.com
- 21. THE EQUILIBRIUM MEMBRANEPOTENTIAL FOR SODIUM IS + 60 mV Na + Na + + - CONCENTRATION POTENTIAL IN OUT www.freelivedoctor.com
- 22. THE RESTING POTENTIALIS NEAR THE POTASSIUM EQUILIBRIUM POTENTIAL AT REST THE POTASSIUM CHANNELS ARE MORE OPEN AND THE POTASSIUM IONS MAKE THE INSIDE OF THE CELL NEGATIVE THE SODIUM CHANNELS ARE MORE CLOSED AND THE SODIUM MOVES SLOWER www.freelivedoctor.com
- 23. EVENTS DURING EXCITATION DEPOLARIZATION EXCEEDS THRESHOLD SODIUM CHANNELS OPEN MEMBRANE POTENTIAL SHIFTS FROM POTASSIUM CONTROLLED (-90 MV) TO SODIUM CONTROLLED (+60 MV) AS MEMBRANE POTENTIAL REACHES THE SODIUM POTENTIAL, THE SODIUM CHANNELS CLOSE AND ARE INACTIVATED POTASSIUM CHANNELS OPEN TO REPOLARIZE THE MEMBRANE www.freelivedoctor.com
- 24. OPENING THE SODIUMCHANNELS ALLOWS SODIUM TO RUSH IN THE MEMBRANE DEPOLARIZES AND THEN THE MEMBRANE POTENTIAL APPROACHES THE SODIUM EQUILIBRIUM POTENTIAL THIS RADICAL CHANGE IN MEMBRANE POTENTIAL CAUSES THE SODIUM CHANNELS TO CLOSE (INACTIVATION) AND THE POTASSIUM CHANNELS TO OPEN REPOLARIZING THE MEMBRANE THERE IS A SLIGHT OVERSHOOT (HYPERPOLARIZATION) DUE TO THE POTASSIUM CHANNELS BEING MORE OPEN www.freelivedoctor.com
- 25. GRADED VS ALLOR NONE A RECEPTOR’S RESPONSE TO A STIMULUS IS GRADED IF THRESHOLD IS EXCEEDED, THE ACTION POTENTIAL RESULTING IS ALL OR NONE www.freelivedoctor.com
- 26.
- 27.
- 28. PROPAGATION OF THEACTION POTENTIAL +++++ -------- --------------------- +++++++++++++ AXON MEMBRANE INSIDE OUTSIDE ACTION POTENTIAL DEPOLARIZING CURRENT www.freelivedoctor.com
- 29. PROPAGATION OF THEACTION POTENTIAL +++++ -------- --------------------- +++++++++++++ AXON MEMBRANE INSIDE OUTSIDE ACTION POTENTIAL DEPOLARIZING CURRENT www.freelivedoctor.com
- 30. PROPAGATION OF THEACTION POTENTIAL --+++ ++------ +++------------------ ---++++++++++ AXON MEMBRANE INSIDE OUTSIDE ACTION POTENTIAL DEPOLARIZING CURRENT www.freelivedoctor.com
- 31. PROPAGATION OF THEACTION POTENTIAL -------- +++++ ++++++------- -----------++++ AXON MEMBRANE INSIDE OUTSIDE ACTION POTENTIAL DEPOLARIZING CURRENT www.freelivedoctor.com
- 32. SALTATORY CONDUCTION +++++-------- -------- +++++ AXON MEMBRANE INSIDE OUTSIDE ACTION POTENTIAL DEPOLARIZING CURRENT MYELIN NODE OF RANVIER NODE OF RANVIER www.freelivedoctor.com
- 33. NORMALLY A NERVEIS EXCITED BY A SYNAPSE OR BY A RECEPTOR MANY NERVES SYNAPSE ON ANY GIVEN NERVE RECEPTORS HAVE GENERATOR POTENTIALS WHICH ARE GRADED IN EITHER CASE WHEN THE NERVE IS DEPOLARIZED BEYOND THRESHOLD IT FIRE AN ALL-OR-NONE ACTION POTENTIAL AT THE FIRST NODE OF RANVIER www.freelivedoctor.com
- 34.
- 35. THE SYNAPSE JUNCTIONBETWEEN TWO NEURONS CHEMICAL TRANSMITTER MAY BE 100,000 ON A SINGLE CNS NEURON SPATIAL AND TEMPORAL SUMMATION CAN BE EXCITATORY OR INHIBITORY www.freelivedoctor.com
- 36. THE SYNAPSE SYNAPTICVESSICLES ••• ••• ••• ••• ••• ••• ••• ••• ••• INCOMING ACTION POTENTIAL CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME www.freelivedoctor.com
- 37. THE SYNAPSE SYNAPTICVESSICLES ••• ••• ••• ••• ••• ••• ••• ••• ••• INCOMING ACTION POTENTIAL CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME www.freelivedoctor.com
- 38. THE SYNAPSE SYNAPTICVESSICLES ••• ••• ••• ••• ••• ••• ••• ••• ••• INCOMING ACTION POTENTIAL CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME www.freelivedoctor.com
- 39. THE SYNAPSE SYNAPTICVESSICLES ••• ••• ••• ••• ••• ••• ••• ••• ••• CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME www.freelivedoctor.com
- 40. THE SYNAPSE SYNAPTICVESSICLES ••• ••• ••• ••• ••• ••• ••• ••• ••• CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME ••• www.freelivedoctor.com
- 41. THE SYNAPSE SYNAPTICVESSICLES ••• ••• ••• ••• ••• ••• ••• ••• ••• CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME www.freelivedoctor.com
- 42. THE SYNAPSE SYNAPTICVESSICLES ••• ••• ••• ••• ••• ••• ••• ••• ••• CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME www.freelivedoctor.com
- 43. POSTSYNAPTIC POTENTIALS RESTINGPOTENTIAL EPSP TIME www.freelivedoctor.com IPSP
- 44. TEMPORAL SUMMATIONTIME TOO FAR APART IN TIME: NO SUMMATION www.freelivedoctor.com
- 45. TEMPORAL SUMMATIONTIME CLOSER IN TIME: SUMMATION BUT BELOW THRESHOLD THRESHOLD www.freelivedoctor.com
- 46. TEMPORAL SUMMATIONTIME STILL CLOSER IN TIME: ABOVE THRESHOLD THRESHOLD www.freelivedoctor.com
- 47. SPATIAL SUMMATIONTIME SIMULTANEOUS INPUT FROM TWO SYNAPSES: ABOVE THRESHOLD THRESHOLD www.freelivedoctor.com
- 48.
- 49. NEURO TRANSMITTERS ACETYLCHOLINE DOPAMINE NOREPINEPHRINE EPINEPHRINE SEROTONIN HISTAMINE GLYCINE GLUTAMINE GAMMA-AMINOBUTYRIC ACID (GABA) www.freelivedoctor.com