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Digoxin -mechanism of action

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Cardiac glycoside mechanism of action

Oh hello everybody so this video i have made to describe the charism of action of carne a cloud-like oh sides okay so can you carry clio sizer drugs which are positive inotropic drugs used in heart failure now basically what happens in now heart failure there are two types of heart period that is systolic and diastolic in systolic type of heart failure the heart is

Not able to pump enough amount of blood required for the body right so what happens is the cardiac output or ejection fraction decreases below the requirement of our body okay so for treating the heart failure we may use various spectrum of drugs and correct like oh site is one of them correct like oh sites are group of drugs which basically only provide symptomatic

Relief we don’t actually help in decreasing the pathophysiology but they improve the contractility of myocardium now basically what happens is by the card apply cosine the force of contraction increases right and we will we all know that as the force of contraction increases the cardiac output increases and that’s what we want in heart failure right now we have

Various group of we have various drugs included undergraduate carries micro sites like decoction digitoxin oban but at present only one drug is used clinically and that is digoxin okay so digoxin is used clinically nowadays okay now we will see mechanism of action okay now first will i’ll show you what happens normally during the cardiac cycle right now during

Depolarization now we all know that deeper means the membrane potential going towards less negative value right and when that occurs the voltage-sensitive l-type calcium channels open okay so we see here and as soon as the action potential arrives here the voltage sensitive l type of calcium channels open now this is the membrane this is the intracellular part of

A cardiac muscle fiber and this is the extracellular part okay so as soon as the action potential arrives the voltage sensitive any type of calcium channel opens okay and the calcium comes in the calcium enters inside be safe okay now this is the trigger calcium okay now this trigger calcium will stimulate the right totin receptor of the sarcoplasmic reticulum now

Inside the cell we have sarcoplasmic reticulum that is endoplasmic reticulum of cardiac muscle fiber okay now this sarcoplasmic reticulum is full of calcium it is it has abundant amounts of calcium and this small amount of calcium that is entered from outside is going to stimulate it i not intercepted and large amount of calcium would be released from cytoplasmic

Reticulum to the inside of the cell now we all know that calcium is required for the fourier for the breaking of active micing complex and for causing contraction right i’m sorry for the formation of actin-myosin complex and for contraction right so so these calcium will cause contraction okay now for relaxation what is going to happen let’s see that okay now

For relaxation we see here that this calcium has to somehow go thrown it has to move out of these cytoplasm okay or else it is going to continuously this form this in actinomycin complex and the muscle will continuously contract right but it has to go inside so what happens is this ser ca2 saarc a – is going to pump all the scale sim back into the sarcoplasmic

Reticulum okay ser ca2 is going to cause all the consumer back into plasmic reticulum okay kelsey quest stream which is going to store the which is which forms complex with the caption okay now remaining small amount of calcium moves out of these cells by ncx empty porter in exchange of sodium 3 sodium comes in okay so a major amount of caption goes into the

Sarcoplasmic reticulum and a small amount of calcium goes out by ncx energy circuit in exchange of 3 sodium that is 3 sodium comes in okay now this calcium has to go inside this or has to go outside for relaxation to occur okay and in exchange 3 sodium has came in okay now this 3 sodium that has just entered will move out and do potassium will come in okay 3

Sodium will could move out and two potential will come in my sodium potassium atpase pump okay whole cycle the caption has moved out and moved into back into the sarcoplasmic reticulum so it is not present in the cytoplasm now so relax ation of course so this is how normally the cardiac cycle goes on in the in the myocardium okay so now what happens is decock

Seen as he’ll be coxie you know inhibits the sodium potassium atpase pump and we imagined that this pump is inhibited so what happens is potential doesn’t move in sodium doesn’t move out now what what does this go into cause that is there is going to be slow accumulation of sodium inside the cell because this is not working the sodium is not moving out the sodium

Is going to accumulate now this sodium is going to rise slowly absolutely inside the cell you know this sodium is rising so sodium outside will not be able to come inside because gradient is not maintained the sodium inside is rising and that’s why the outside sodium won’t be able to come inside now this sodium is not able to enter so calcium is not going to be

Able to move out so ultimately after all that the calcium is going in thee it is going to get accumulated in the cell okay now slowly what the cell will do is it will pump the calcium into the sarcoplasmic reticulum so after every cycle large and large amount largely large amount of calcium will be able to accumulate inside the cell now so we know that calcium is

Responsible for the contraction so more calcium means more more activation of more number of atomizing complex and more forceful contraction so this is how it basically works because and we do this so what will happen is sodium is not able to me it’s not going to be able to move up sodium is going to accumulate the radial it is not maintained and that’s why sodium

Is not able to come inside and that’s why this pump is also not working much and that’s why calcium is also not going out so catching slowly accumulates and sr are in the cytoplasm as well as in the sarcoplasmic reticulum and that’s why after every contraction there will be more release of calcium from sarcoplasmic reticulum and that’s very force of contraction

Will be more after every cycle

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Digoxin -mechanism of action By medical videos