Since the concept of being below is itself somewhat vague, scientists define the nadir in more rigorous terms. Specifically, in astronomy, geophysics and related sciences (e.g., meteorology), the nadir at a given point is the local vertical direction pointing in the direction of the force of gravity at that location.
anatomical dead space. In pulmonary physiology, the area in the trachea, bronchi, and air passages containing air that does not reach the alveoli during inspiration and is not involved in gas exchange. This is termed dead space because the air does not reach the alveoli and is not involved in gas exchange. Normal anatomical dead space is 2.2 ml/kg or 1 ml/lb.
(1)Department of Anaesthesia, University Hospital, Lund, Sweden. Deadspace is defined in terms of the efficiency of the lung in eliminating carbon dioxide. The airway deadspace is the volume of the airway in which gas moves chiefly by convection.The alveolar deadspace is caused by ventilation/perfusion inequalities at the alveolar level. The commonest causes of increased alveolar deadspace are airways disease--smoking, bronchitis, emphysema, and asthma.Other causes include pulmonary embolism, pulmonary hypotension, and ARDS.1)Department of Anaesthesia, University Hospital, Lund, Sweden. Deadspace is defined in terms of the efficiency of the lung in eliminating carbon dioxide. The airway deadspace is the volume of the airway in which gas moves chiefly by convection.