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.
Types of Ostomies and Continent Procedures. The terms ostomy and stoma are general descriptive terms that are often used interchangeably though they have different meanings. An ostomy refers to the surgically created opening in the body for the discharge of body wastes. A stoma is the actual end of the ureter or small or large bowel that can be seen protruding through the abdominal wall. The most common specific types of ostomies are described below.