A levwl biology unit 3 lung disease data

Can someone plz exaplin this to me. Thanks!

Hi, I found this confusing as well but my teacher explained it to me this way:

FEV is the maximum volume of air that can be breathed out in one second, so it's essentially the rate of how fast a certain volume of air can be expired.

FVC is the maximum volume of air that can be breathed out in one breath - another way to think about it is the lung volume/capacity.

With asthma, the lung capacity is exactly the same, so the FVC doesn't change, and the same volume of air could still be forcefully breathed out (even during an asthma attack), but it would take longer to do so. The FEV for asthma would decrease, as in one second, less oxygen can physically be breathed out of the airway due to the diameter of the airway decreasing.

With fibrosis, scar tissue formation means that the lungs can expand less, so the capacity of the lungs decreases (the FVC). A patient with fibrosis will not be able to forcefully breathe out the same volume of air, compared to when they were healthy, as their lung volume has decreased.

I hope this helps

Hi. Thanks i really appreciate the help! I have a question tho. Wouldn't a decrease in air breathed out per second due to diameter decreasing, directly affect the concentration gradient of co2 at the alveoli so reduced FVC too because the alveoli would then be filling with less air to normal, and breatg out less forcefully. Thanks!