in the last video I have mentioned the apparatus required for amphibian experiments and the connections of the primary CC secondary CC and still I will mention few things but mainly I will discuss the different graphs how we will M how we will obtain different graphs from this apparatus now first see I have already mentioned that the Nal we take that is gastrous muscle with this long tendon and knee joint above and below the origin of the Gast muscle will cut the knee joint and side long side KN with a piece of veral color it helps in hanging this is the nasy preparation we will take in vitro for getting the different carvs of the cardiac muscle sorry of the scal muscle of the toad first of all you have to mount the non musing preparation we Mount the nonm preparation what the this Myra board this is myograph board the rectangular box with box in it and this is the m stand who holds the MRA Bo and the proximal L there is a p and long arm of the this is longer longer and this is shorter this portion is the shorter this this portion is the short ter this is the longer of the isotonic liver so this this is the apparatus contains MRA board with MRA stand with a isotonic liver which has a long arm and a short arm long arm is pointed for getting the point carves this will act as a stylus and the short with the help of shortterm see there are some holes are there we with the thre and needle we hook the long tendon of the gastrous muscle we won't touch the muscle itself the so that cannot get stimulated before so that the muscle cannot get stimulated before we will only hook the G tendon of the gastrous muscle now we will place put up Al what the knee joint of the gous of the to the and below the knee and below the gous muscle there's a knee joint we pin the knee joint and we what will happen we have to first we have to make the we can do it in preloaded preparation or in after loed prep both but in preloaded preparation what we have to do we have to make the we have to the see that the afterload screw is not touching the stylus so in the pre preparation we have make the stylus what done we have to make the sty horiz to get the car so we have made the horiz by putting the knee pulling the muscle and putting the knee joint over the B board and the sa knot will hang over the secondary lifs piece of heart colum will help in hanging and the appus St is this is duas induction coil the fadic T will be produced in the fic or IND kind the produce in the secondary circuit first our voltage in our room is the 220 volt AC current and that should be an instrument over there and there was an instrument in this department that is called Step Down Transformer that St down transformer converts the 220 Vol AC current to 2 to6 Vol DC current and that D Cur from switch here Will coming to the this screws of the primary circuit from the primary circuit two words are going to the contact block so this is the from primary fil the screws are going to the contact block contct two SP of the contct this is primary circuit and when the current is fit in the primary circuit there is a instant current or induced current over the secondary circuit and from the secondary circuit the secondary circuit thetic n will be stimulated if we give one induction C we can by this instrument we can give one induction one stimulation multiple stimulation at regular intervals and also through if the D induction is not available then we can use this student stimulator also see the student stimulator this is off on switch here from this the apparatus inside this apparatus everything is ready and from there the output current that the current that will be given to the Nar musle preparation that output current is here see output is written this output current will be 0 to 15 Vol DC current 0 to DC current DC current because when we are giving a single stimulus is is the instant current and we can and these two will go to the contact block so this is the secondary circuit this is the primary Circ this two will go over here if we use the if we do not use this div induction coil if we use the student tempor this two screw will go two w will go for the two screw this is a par ccle and you have to make the this is external this is the light and there's a pulses if we give multiple stimulus to see the clonus titanus and trippy you have to give the pulses and you can determine the how how many voltage we will require this is the pulses and voltage 0 to 15 we can take it 10 or six like that so with the help of student stimulator we can regulate the duration frequency and pulses and multiple stimulus or single stimulus all things you can make we can give to the N muscle preparation by this student stimulator so connection is from this output this will go to the electrod so in the electr the will be there this two words will go to the contact FL this is about the student stimulator now first what will happen first we have mounted theed pration we have mounted the non musle de but if you want to mount it in after that I show you later on first make the sty start the smoked drop diagram is already smoke sorry smoke cylinder and what we do the skeletal muscle for doing the experience of the skel musle 64 64 is a rotation speed mm per second see now see this is the Bas line this is uneven smoking so B we are not getting the very good Bas line over here this the Bas line Bas line after getting the Bas line we can this is the tuning part for getting the time tracing what you have to do you have to it like this hold it over here and just below the Baseline you have to place the tip of the tuning for that there is this act stylus then you get this and make the drums on then we'll get this time tracing this is time tracing of 100 frequency tuning for is of 100 frequency Heartz so for each Peak duration of each Peak is 01 second from this peak to this PE every Peak the duration of every PE is 01 second so with the help of this tuning for this is the stylus of the T for we get the timeing below the Bas line first then what we have we do we'll just without starting the drum we just get the point of stimulus like this point of stimulus this is point of stimulus now so everything is ready either this you can use the Str stimulator or you can use the div induction coil now what will happen we from the primary coil induced c will be produced in that is of instant current one single current so that the muscle is not damaged if you first we get one on switch on the C and then what will happen there will be single rotation and the there will be induced Cent produced over here or from there this Curr Curr will be coming to the will come to the of the then the impulse will travel impulse that is action potential will the then the action potential we go to the motor inflate of the gous muscle from the motor inflate The neovascular Junction release of acine and from that acine there generation of EP then suction of EP and there development generation of the action potential and that action potential will travel by the Tes to the of the mus Tes to the copas reticulum and from the culum calcium will be released and then you know there action potential man will contract and there contraction of the muscle and if the J is rotating we we get the graphical representation of the card of a single symb if we give one single induction shock only and then you remove the stimulus and of the switch we'll get the single induction shock effect of single induction so if this graph is given to you during your exam what will you be answer your answer will be this is the graphical this graph shows graphical representation of the effect of single stimulus on isolated nard muscle preparation this graph actually what we are getting is a simple muscle twitch now what are the parts of this graph parts of this graph is see this is the a is the point of stimulation B is the point of contraction D is C is the midpoint D is the point of relaxation and the period a is the Latin period BC is the period of contraction CD is the period of relaxation and c e is the height of contraction this is the base line and this is done in preloaded preparation so we are getting the physiological curves below the base line now below that there is a time tressing from the time tressing you have to mention the periods of ltin period period of contraction period of relaxation AB is the Latin period see the ab is point single in between the two waves the timing is 01 second as because it is 100 HZ frequency so it is 01 second here you will get see there are six like CS like like this so the point of from the point of stimulation you have to count the period of contraction this is the height of contraction from here relaxation is starting so period of contraction is 06 seconds six PS are there six intervals are there so 06 second and period of relaxation is CD here 8 intervals are there eight PS are there so 08 second so the in the book it is written 01 second is the Latin period and 04 second is the period of contraction and here it is and period of relaxation is 0.7 again total period of contraction is .1 second but here we are getting more 0 6 second is the period of contraction 8 second is the period of relaxation you will mention that this is due to the inertia of the instrument and the inertia of the liever for this reason this is in over here this is done in vro and there is a in lots of long inertia of this stylus for this reason we are getting a and the instrument also so we are getting the long duration of the period of contraction and period of relaxation now AB is the Latin period what is the cause of Latin period Cause of Latin period is I have already mentioned this is the P time taken for the the impulse to travel from the point of stimulation up to the point of contraction is the flatin period the cause of Lattin period is cause of Latin period is the time taking for the impulse to travel from the s n after the motor plate of the gastrous muscle and time taken for the release of neur acid cooling from The neurovascular Junction generation of PPP and gener time taken for the generation of action potential and that action potential will propagate through thees up to the C reticulum from the cing reticulum the calcium will be released plus there is a viscosity of the muscle itself and inertia of the LI also contributes for the Latin period now you have to count that that this is the cause of Latin period these are all three are the simple muscle C so everywhere you have to count the Lattin period in each each carve you are observing that that there is physiological curve that means carve has gone below the Baseline why because of the long momentum of this longer of the this stylus during if it is rotates like this now this is the point of stimulation and if the Nar is stimulated we will give the drum will cylinder will move and we'll get the graphical representation of the curve like this the see the upst this the period of contraction is very sharp because it is an active process and stylus move very faster but this is the relaxation is very slower so it is taking a long time because the stylus is going down because of the gravity of the muscle and the calcium is also pumped back into the cytoplasm reticulum so the time taken this is this is due to gravity it is the styze is coming down or falling down so it is see the duration is longer here and it is faster it is due to gra action of the gravity but if we do it if we make the stylus horizontal with the help of this screw the screw touches the short metal plate and the metal plate that means we making the sty is horizontal with the help of this metal plate so before in preloaded preparation muscle was bearing the load of the stylus before contraction so there is stretching of the muscle and also during contraction so at the if the stretching of the mus within physiological limit more will be the stretching more will be the force of contraction so in case of pred preperation we'll do the simple muscle car or simple muscle twitch because we'll get the High contraction in of that preloaded preparation but after loed preparation see I have make the sty horizontal with the help of screw that mean the screw is touching the metal of the this at the level of the F so what is happening if we now give the stimulus over here we get a like this C like this of the simple musular card but we won't get the from the Baseline we will getting the physiological card from the Baseline the carve will go above because it is during coming down below it is getting attach with the metal plate so we are not getting the in case of after loaded preparation we will not get the physiological car carb will come from here up to here directly from here but in after loed preparation height of contraction will be also less because there is no stretching of the muscle before contraction so after loaded preparation the height of contration will be less and there will be no physiological carve the carve will come from the Baseline up to from here but in case of preloaded preparation muscle is bearing the load before contraction and also during contraction and there is before contraction there is stretching of the muscle so what is happening the height of contraction will be more now during exam it will be asked to count the period of contraction period of relaxation whether it is done in pre-loaded or after loaded preparation you you will count the number of PS and number of gap between the two PS then you will will able to you have to don't say the from the book but you have to count from here and then you have to mention the Lattin period period of contraction period of relaxation you have to count the pics or the gap between two PS gap between two PS is a 01 second in that way and if it is below the Baseline it is done in preloaded preparation if you see the physiological cve see here and here there this is a carb is going below to the Baseline preloaded preparation contraction height of contraction more and physical guard will be there in after loaded preparation he of cont will be less and there will be no physiological card this is about the effect graphical lition of effect of stimulation of the N isolated NM preparation by single induction shock now if we apply multiple induction shock to the nous isol non muscle preparation at regular intervals what we will get we'll get this type of car this is called fattic C ftic after seeing this card you will mention this is the graphical representation of application of multiple stimulus at regular intervals showing the effect of fattic now how will you understand the muscle is fattic gradually the Lattin period will increase and the height of contraction will decrease now see first suppose first one or two this is the normal this is the first C this is the latent period this is the point of contraction and this is a point of stimulation this is the point of contraction first this if this is the first curve first cve is this second and third car height of contration increases and Lattin period decreases so what is due to this is due to the beneficial effect of the muscle what is beneficial effect during B the temperature we are getting more and stimulus so first second third four what will happen the height of contraction will increase because the viscosity of the muscle or elasticity of the muscle decreases because of the more and more stimulation and more and more calcium will be available and temperature will increase for this season these are the causes of beneficial effect we get the height of contraction will increase and L Peri decrease but later on see the height of contraction decreases and latent period increases latent period increases es now see ultimately what is happening the muscle is remaining the height of con decreases latent period increases muscle remain in a contact state it is not going touching the base line why it is not touching the base line because muscle the the fatig has occurred within the muscle this portion muscle remain in a contracted State see this is the muscle remain in a contracted State this is not this are going below the Baseline before now muscle remain in a contact St so muscle remain in a contracted State this is called contraction remainder this is called contraction remainder what contraction remainder what is contract muscle remain in a contracted State there is no relaxation of the muscle why muscle remain in a contact State because there is loss of ATP so calcium cannot be pumped back into the coplas reticulum so if then it will be asked whether this contraction or ftic of the muscle has occured reversible or irreversible this is a reversible phenomenon because if we take give some time to the muscle and apply some FR Sal that is 0.6% normal Sal FR Sal to the preparation then muscle revive again and if you get the stimulus then again we will get the CVS and if the if you want to see the two ltin period of the muscle we directly stimulate the muscle we'll get the stimulus and Latin period will be shorter that is the true ltin because that in that Cas the time taking n will not be required will not be there so two L if the muscle will directly stimulate the muscle now see this is contraction Remer you will be asked this is reversible or irreversible your answer will be it is reversible now where is the seat of fatty seat of fatty will be the neuromuscular Junction in vitro in v it will be the central signups then it will have can you say whether this is done in preloaded or after loaded preparation yes it is done in preloaded preparation because physiological curves are there but now the muscle it is the contraction remainder muscle remain in a contracted State there is no relaxation of the muscle so muscle is not good touching the base line it is remain in a contracted State these these are all and this is time toing these three carvs are see these three cars are for ptic C and if if we do the preloaded preparation the fattic PRI preparation muscle will be easily fat because it is stressed muscle is already stressed preloaded preparation because stus is bearing the weight of the muscle before contraction and during contraction so F will occur earlier but if you do it in after preparation F will take more time to become F muscle become F now this is the card for appliation of the temperature hot and cold saline normal Sal or FR saline we will effect of temperature see this is the normal car this is the normal car now after that we are applying up to 40° C not more than that then muscle will be denatured so 40° C fingering saline this is the normal cup so what is happening Latin period shorten height of contraction increases again due to beneficial effect everything you will mention and here the Lattin per 10° C prox saline is applied so what is happening after some time we appli prox saline height of cont decreases Latin period increases and this is the time to see this is also the hot and cold see this is the normal one normal one this is this is hot this is cold this is also this is also the effect of temperature effect of temperature now this is the application of two successive stimuli these are the original curves this is the two success application of the two successive stimula how we apply two successive stimula we bed the ster like this first we are getting one make Curr then you are getting one contraction and then again make current another contraction but this is falling on the Latin period of the muscle this is falling on the ltin period of the muscle so we don't get any we won't get any contraction if the second s is falling over the that but if we separate it we can measure it by this also if we separate it first we are getting first contraction and second contraction on the period of contraction then height of there will be summation of the contraction and height of contraction will increase now if [Music] we make the distance more then first contraction will get and if the second make indu contraction falls on the relaxation period of the muscle we'll get second contraction relaxation will be incomplete and we will get the second contraction and that in that case height of contraction will be more than the first Contra this is about the second effect of second stus now after doing this different cars for this cylinder with the smoked paper we cut the paper where there is no then that card should be immersed in a bow the bow contains 2% C res or in meth spirit for varnishing and permanent permanent what we have done here for permanent fixation of the graph with the paper so see all these are permanent fixation after varnishing or 2% C resin cellc or resin in me speed we will imge that from that we put it dry it in here then we'll get this fixed card then you get this fix card all these cards are here so these are the something about the some cards I have mentioned and there are two or three cards you read it from the book thanks