BIOM20002 Lecture Notes - Lecture 53: Lung Volumes, Trachea, Electronvolt
Document Summary
Residual volume (rv): volume of air remaining in lungs after a maximal exhalation. Can"t breathe this out because lung would collapse. If (cid:449)e do(cid:374)"t k(cid:374)o(cid:449) (cid:449)hat zero is the(cid:374) rv a(cid:374)d frc (cid:272)a(cid:374) o(cid:374)ly (cid:271)e a(cid:374) esti(cid:373)ated (cid:449)ith spirometry. Can determine these values with a helium dilution method. Take a bell (known volume) with known conc of helium. Person breathes in and out until helium conc equilibrates. Breathe in then breathe out vital capacity as quickly as possible. This is the forced vital capacity (this can be slightly less than vital capacity since when you force out air some bronchioles can be constricted) Fev1/fvc = percentage you can blow out in 1 second. Should be about 80%, less may mean obstructive lung disease. Residual volume actually increases because you reduce how much you can get rid of when you exhale. Vital capacity decreases because you are able to move less air. But if tlc decreases then vital capacity must decrease.
