T23:ANATOMICAL DEAD SPACE
Anatomical dead space
The entire respiratory system is separated into two parts, the conductive, and the respiratory parts. The conductive is everything that is connected from the nose to the terminal bronchioles. Air is moved throughout the conductive parts, but O2 and CO2 are not exchanged.
This lack of gas exchange gives rise to the name dead space. The dead space of the lungs is approximately 150 ml.
Conductive(anatomical dead space) – Nose, Pharynx, Larynx, Trachea, Bronchi, Terminal Bronchioles
Respiratory – Respiratory Bronchioles, Alveolar Duct, Alveolar Sac
Physiologic dead space includes all the non-respiratory parts of the bronchial tree included in anatomic dead space, but also factors in alveoli which are well-ventilated but poorly perfused and are therefore less efficient at exchanging gas with the blood. Because atmospheric PCO2 is practically zero, all the CO2 expiredin a breath can be assumed to come from the communicating alveoli and none from the dead space. By measuring the PCO2 in the communicating alveoli (which is the same as that in the arterial blood) and the PCO2 in the expired air, one can use the Bohr Equation to compute the “diluting,” non-CO2 containing volume, the physiologic dead space.
This lack of gas exchange gives rise to the name dead space. The dead space of the lungs is approximately 150 ml.
Conductive(anatomical dead space) – Nose, Pharynx, Larynx, Trachea, Bronchi, Terminal Bronchioles
Respiratory – Respiratory Bronchioles, Alveolar Duct, Alveolar Sac
Physiologic dead space includes all the non-respiratory parts of the bronchial tree included in anatomic dead space, but also factors in alveoli which are well-ventilated but poorly perfused and are therefore less efficient at exchanging gas with the blood. Because atmospheric PCO2 is practically zero, all the CO2 expiredin a breath can be assumed to come from the communicating alveoli and none from the dead space. By measuring the PCO2 in the communicating alveoli (which is the same as that in the arterial blood) and the PCO2 in the expired air, one can use the Bohr Equation to compute the “diluting,” non-CO2 containing volume, the physiologic dead space.
(Source: drdipak)
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