The Video lecture from Gaseous Exchange (F.Sc. First Year Biology) covers the mechanism of voluntary and involuntary breathing in human beings. It explains the two step process of inspiration and expiration in series of steps involving rib cage, intercostal muscles, diaphragm and lungs. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional and commercial purpose by keeping the credits to Maktab.