Ch 15Breathing and Exchange of Gases — Class 11 Biology, concept-first.

Every living cell needs a continuous supply of oxygen to carry out aerobic respiration, and must equally get rid of the carbon dioxide that this respiration produces.

The human respiratory system is a single, continuous, branching passage running from the two external nostrils down to the microscopic alveoli deep within a pair of lungs, and every organ along this p…

Breathing is the rhythmic, repeated process of drawing air into the lungs (inspiration) and expelling it back out (expiration), and unlike the heartbeat, it is driven not by any muscle contracting dir…

A person's breathing can be measured and broken down into a standard set of respiratory volumes and capacities, most directly recorded using an instrument called a spirometer, which traces the volume…

Once inspired air has reached the alveoli deep within the lungs, the actual exchange of gases between this alveolar air and the blood in the surrounding pulmonary capillaries -- and, correspondingly,…

Diffusion across the alveolar membrane, described in the previous section, brings oxygen into the blood and removes carbon dioxide from it at the lungs; but the blood must then physically carry this o…

Oxygen is transported in human blood by two parallel routes, though these two routes are very far from equal in how much oxygen they actually carry.

Carbon dioxide, generated continuously as a waste product of cellular respiration in every tissue of the body, is carried back to the lungs by blood through three separate, parallel routes, rather tha…

Breathing proceeds automatically and rhythmically throughout life, entirely without conscious attention, yet it can also be brought briefly under voluntary control -- as when a person deliberately hol…

Although the respiratory system is remarkably robust under ordinary conditions, several distinct disorders can significantly impair its normal function, broadly falling into an allergic airway disorde…

This chapter surveyed how gaseous exchange is achieved across the animal kingdom and, in detail, how it is achieved in humans.