Lung compliance Physiology | Hysteresis in lung pressure volume curve | Respiratory physiology 

The best one out there.

I absolutely loved how you explained this super important concept! You went all the way to physics to make it super comprehensible! Thank you so much for sharing your knowledge!

This video just made my day! I finally understood these concepts. Thank you so much!

Thanks medam for clearing the concept in a simple way , glad to have teacher like u ♥️♥️

You explained this so well, such a life saver! Thank you heaps:)

Por fin, después de 19 años de mi vida, he aprendido a interpretar un gráfico de este tipo. Te agradezco muchísimo, de verdad, greetings from Spain, new subscriber :D

Thank you soooooooo much for giving us such type of quality explanation❤❤❤❤👍👍👍

Thank you so much .your explanation really helpful ..

Its really awesome mam. The concepts are very clear. So helpful

Thankyou ma'am Jaise aap concept explain krte ho toh topics samaj me aata hai 🙏🏻🙏🏻🙌🏻🙌🏻

Wow my mind is blown. Thank you

Mam you have explained a difficlt concept in a simlpe way and beautifully.thanx

Thank you very informative 👍 👏

Thankssssss mam for suchhhh a crystal clear explanation,thnks a lott👍

Mam I have struggled very much to understand why compliance is more in expiration than inspiration U have explained it beautifully at 6:15 THANK YOU MA'AM

Ma'am your videos are really helpful. Plz make videos on all the imp and difficult topics of physiology which are left as soon as possible .🙏

Very beautiful lecture 😊

Mam thanks u very much for your lecture

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awesome

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Well explained ❤

Wow Mam thank you so much

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mam would be really helpful if you could make a vedio on static ,dynamic compliance

buenísimo muchas gracias!

Mam 🙏🙏🙏you saved my exam tomorrow ❤❤❤

Thankyou mam❤🙏

Ma'am one doubt.. If the intra plural pressure changes from -5 to -8cm H20 during inspiration approximately 500ml of volume will enter the lungs(tidal volume). So if the person has open chest cavity ,so that the pleural pressure is equal to atmospheric pressure ,then howmuch change in pleural pressure will be there to achieve some tidal volume during inspiration

In Graph at 6.21, in expiration limb, initially for a greater transpulomonary pressure change volume expired is very less but since elastic recoil of lung is big here, more volume should change relatively than to later part of expiration. Why is it not happening ? Kindly advice some reason. Thank you.

Ma’am 🙏🙏

Mam, both compliance and elastic recoil depends on elastic fibres, then why they are inversely related to each other

Mam during expiration surfactant concentration increase and decreases surface tension , so can i say during expiration lung compliance is more than lung compliance in inspiration!!? Is during expirationcan we use the term compliance???

3.Condition in which FRV decreases

During inspiration intrapleural pressure is less negative not same as inspiration than transpulmonary will be different

Mam, when there is no inspiration Or expiration -5 pleural pressure keeps alveoli at 0 atm pressure, then how during expiration the same pleural pressure allows alveoli to reach +1

Ma’am why is the compliance of the lung alone is more than total respiratory compliance, when the lung has a recoil tendency to collapse .

Mam,please have a video on flow volume curves

I love you maam

Mam fromwhere can we get ur notes🙏

I read that Elastic recoil is not the reason for hysteresis as you have explained. Isn't it the surfactant which is responsible for varying pressure-volume curves during inspiration and expiration ?

Ma'am what is the relation between surfactant and hystersis?

What exactly is specific compliance ma'am?

Nice explaination but little fast

What is the answer for 3rd question

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How low and high lung volumes make lung stiff(less compliant)

Mam how (1/thoracic wall compliance)= total compliance - ( 1/ lung compliance) is derived???

Questions on lung compliance: 1. Why is the first breath of a newborn so difficult ? 2. What will happen to lung compliance if some alveoli collapse (atelectasis) 3. Can you think of a condition in which lung stretchability is normal but when calculated- lung compliance will be low. (Hint: we use specific compliance in these cases)

Compliance is not about expansion, it's about deformation (STRAIN)produced per certain amount of STRESS. In case of lung physiology the deformation (STRAIN) is measured in change in volume/original volume. STRESS is that which causes that STRAIN (change in volume) and is measure of Trans pulmonary pressure [intra alveolar pressure(IAP)-intra pleural pressure(IPP) ] The actual formula for compliance is strain/stress. Strain= change in volume/original volume Stress= trans pulmonary pressure Now into your question Even after expiration lungs still have functional residual capacity of 2500ml air inside all alveoli. So even before inspiration the volume of air in lungs is 2500 ml which is V1 Now after normal inspiration (tidal volume) of 500ml the total volume of air now in lungs is 3000ml = V2 Change in volume= V2 - V1 That equals to (3000 - 2500)=+ 500ml That positive sign indicates the stress is tensile and is stretching in nature. Now come to strain STRAIN = change in volume/original volume(V1= 2500ml) Calculate it STRAIN = 500/2500 = 1/5 Now STRESS= trans pulmonary pressure at end of inspiration { Tpm} Tpm = IAP - IPP At end of inspiration IAP = 760mmhg IPP = 754 mm hg So Tpm = 760 - 754 Tpm = 6mm hg Now come to compliance C = strain/ stress C = 1/5×6= 1/30 [ml/mmhg] The inference is for a stress(pressure) of 30 MMHG the strain (deformation or volume change) is 1ML. So for inspiration the lung compliance is 1ml per 30 mm hg Now let's calculate for Expiration Before expiration that is at the end of inspiration the volume of air in lungs is 3000ml Now V1= 3000ML And now stress is elastic recoil of alveoli which increase pressure and produce change (deformation) After normal expiration (T.V) of 500 ml the final volume V2 is 2500 ML So change in volume is - (V2 - V1) The negative sign indicates the elastic recoil of alveoli is of compressive stress So change in volume is - (2500 - 3000) U will get 500ML Now for strain = change in volume/ original volume STRAIN= 500/3000 = 1/6 (no units) Now for stress (Tpm) Tpm at end of expiration is IAP- IPP IAP at end of expiration is 760 mm hg IPP at end of expiration is 758 mm hg Tpm = IAP- IPP Tpm = 760 - 758 = 2mm HG Now for compliance C C = strain/stress = 1/6×2 = 1/12 [ml/mmhg] The inference is for a stress of 12 mm hg the strain is 1ml So during inspiration for producing a change in volume of 1ml u need 30 MMHG But in case of expiration for producing a change of 1ml u just need 12 MMHG. Final take = for a very little stress if we produce more change it has more compliance Compliance of lungs is higher in expiration than in inspiration bcoz in expiration a less stress(pressure) produces more change in volume That's it