On the action of the muscular coat of the bronchial tubes in respiration / by C. Radclyffe Hall.

Date:
1850
Catalogue details

Licence: Public Domain Mark

Credit: On the action of the muscular coat of the bronchial tubes in respiration / by C. Radclyffe Hall. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    the two excitations were in operation together, and that, either, one prevailed because it became the stronger of the two, or else because volition interfered. Thus, after a moderate expiration, if a man holds his breath as long as possible, the immediate desire will be for inspiring. Here there are carbonized air to excite expiration, and capillary distension to excite inspiration. As the lung is but imperfectly filled, the latter condition predominates in intensity. The bronchia] tubes having left off with expiration, are kept below their medium size; their contractility is tired out, and their elasticity tends to enlarge them up to their medium calibre. On every account the tendency is towards inspiration. But let the breath be held after a full inspiration, and the conditions are reversed. The expanded bronchial tubes tend to return by their elasticity down to the medium calibre, their stretched and speci- fically excited muscular coat tends to contract, the tubes and cells filled with air, which has become impure, occasion intense desire for expiration, and expiration ensues. If the breath be held at a medium amount of expansion of the chest, so that the conditions are evenly balanced, the subsequent act is that of inspiration or of expiration indiscriminately. By an effort of will we may interfere with these tendencies, because the voluntary movements of respira- tion are stronger than the automatic. By a strong effort, for example, after holding a full, but not the fullest inspiration as long as is comfortable, we may draw in a little more air with momentary relief, but our feelings prove that we are thwarting nature. The automatic arrangements are tending towards expiration, and expiration must follow almost instantly. Thus, inspiration necessarily leads to the condition which is the exciting cause of expiration; and expiration necessarily leads to that which induces inspiration. All tubular muscles appear to respond directly, without the necessary intervention of any nervous centre to the mechanical stimulus of distension; and all are paralysed by over-distension. It is doubtful with respect to the bronchial muscular coat, whether any amount of inspiratory force can call forth this characteristic. The inward rush of air finds so ready a diffusion amongst that which fills the air-cells that these more yielding structures are the parts to suffer from excessive force of inspirations, and intervesicular emphysema, not burst, or dilated, or palsied bronchial tubes is the