The essentials of healthA text-book of anatomy, physiology, hygiene, alcohol, and narcotics . Fig. 41. The respiratory apparatus : (1) the epiglottis; (2) the larynx ;(3) the trachea ; (4) the right lung ; (5) the left lung. sacs, called air cells. The walls of these air cells arevery thin and highly elastic. They can be distended byslight force, and when the force is removed, they can atonce resume their former size. Fig. 42 shows a terminal 9 130 THE ESSENTIALS OF bronchial tube with its air cells. If we bear in mind thatthese air cells have elastic walls, it is easy to imaginehow t
The essentials of healthA text-book of anatomy, physiology, hygiene, alcohol, and narcotics . Fig. 41. The respiratory apparatus : (1) the epiglottis; (2) the larynx ;(3) the trachea ; (4) the right lung ; (5) the left lung. sacs, called air cells. The walls of these air cells arevery thin and highly elastic. They can be distended byslight force, and when the force is removed, they can atonce resume their former size. Fig. 42 shows a terminal 9 130 THE ESSENTIALS OF bronchial tube with its air cells. If we bear in mind thatthese air cells have elastic walls, it is easy to imaginehow they could be inflated, like so many rubber sacs, by forcing air into the tube, at1. This is practically aboutwhat occurs during an ordinaryrespiration. The inner surface of these aircells is exposed to the air whichenters the lungs. The amountof surface thus exposed is verygreat, being estimated to be atleast fourteen hundred squarefeet. Surrounding the walls ofthe air cells is a dense networkof capillary blood vessels. Thusthe blood itself is separated fromthe air only by an extremelyIt is here, in the air cells, that thechanges occur which transform the dark venous bloodinto the bright arterial blood. The Pleura. The pleura is a double membrane, cov-ering the inside of the thoracic cavity and the membrane is closely fastened to the inner wallsof the chest, while the other covers the surface of thelungs. The space between these membranes is calledthe pleur
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysiology, bookyear1
