 This graph is showing record obtained when different temperatures were maintained around nerve muscle preparation and the nerve was stimulated and simple muscle twitch was recorded. Now can you tell that what strength of stimulus will be used for recording this effect of temperature on simple muscle twitch? It has to be supramaximal strength of stimulus as I told in my video on recruitment of motor units that we have to use supramaximal strength of the stimulus to record the effect of any intervention on simple muscle twitch. You can have a look at that video also. The link I have given in the description section below. So in this the center graph that is the black colored graph is recorded at a room temperature say suppose 25 degree Celsius. The blue graph is recorded at a warm temperature say suppose 40 degree Celsius and the brown graph is at cold temperature say 5 degree Celsius. So what are your observations for this graph? So we have to compare the simple muscle twitches which are obtained at warm and cold temperature with respect to the graph obtained at room temperature. So you see the effect on latent period, contraction period, relaxation period and also the strength of contraction the height of contraction which is there. So it is very simple if we see in this graph you see the latent period that is the time taken from the point of stimulation to the start of contraction. It has become less in warmer temperature and it is more in colder temperature. So if we write warm and cold what we will see is latent period decreased in warm and it increased in cold then what about contraction period? Same contraction period also decreased. So from here start of contraction to the maximum height of contraction it is contraction period. So you see contraction period is more in colder temperature. So contraction period is less in warm temperature and cold it is increased. Similar is the thing with relaxation period in warm temperature it is decreased and in cold temperature it is increased. What about the height of contraction? Height of contraction actually has increased in warm you see this is the height of contraction and in cold it is decreased. So it is simple observation what we are seeing here not very difficult right. Now comes the second part that why we are getting what we are getting? What is the reason behind that? Well in warm temperature what happens that there is increased enzymatic reactions right. So temperature actually affects the enzymatic reactions right. So there is increase in enzymatic reaction and the metabolic activities when the temperature increases and because of this there is decrease in resistance in the muscle. So movement will be faster plus the ion channels also open and there is increase in the ionic flow. So that is why there is increase in speed of contraction with decrease in latent period and opposite effect happens at colder temperatures. So enzymatic reactions are going to decrease metabolic reactions are going to decrease the rate of them as going to decrease. Now the same question which I asked for recruitment of motor units what do you think that does this graph violate all or none law or not? What does all or none law says? That either there will be a maximum response or no response at all. So does this graph violate all or none law because we are changing the temperature and we are seeing that there is increase in and decrease also in the strength of contraction. So that maximum which we are obtaining is not actually maximum it is changing. So why is it so? Well this graph does not violate all or none law because all and none law says that either there will be maximum response or no response at all given the baseline conditions this is very important given the baseline conditions are constant. If the baseline conditions change then the strength of contraction will change. So here by changing the temperature we are changing the baseline condition inside the cells that is there is increase in the enzymatic activity increase in the metabolic activity that is why we are getting different response. So that is all about effect of temperature on simple muscle twitch. Thanks for watching the video hope you liked it if you liked it do press the like button share the video with others and do not forget to subscribe to the channel if your physiology is open. Thank you.