6/27/20202.1: General Anatomy of the Respiratory System: Essential Human Anatomy and Physiology I with Lab- Kassner2/13Figure 2.1 Anterior view: Gross anatomy of lungs.The right lung has three lobes (superior,middle, inferior) while the left lung has two lobes (superior, inferior). The right and left lung both haveoblique fissures separating the lobes. The right lung also has a horizontal fissure separating thesuperior and middle lobes.
6/27/20202.1: General Anatomy of the Respiratory System: Essential Human Anatomy and Physiology I with Lab- Kassner1/132.1: General Anatomy of the RespiratorySystemGross anatomyis the study of the organs and structures of the human body visible to the nakedeye. When looking at the lungs from a gross anatomical perspective, the lungs are paired and foundin the chest cavity(Figure 2.1). Notice that the lungs are not symmetrical. The right lung has threelobes: superior, middle, and inferior. The left has two lobes: superior and inferior. This asymmetry isdue the position of the heart, which is situated slightly to the left of the median plane. The hilum isknown as the “root” of the lung. This is where the pulmonary vessels and bronchi enter each lung(Figure 2.2). Healthy lung tissue has a very light texture and is peachy/pink in color.09:13
6/27/20202.1: General Anatomy of the Respiratory System: Essential Human Anatomy and Physiology I with Lab- Kassner3/13Figure 2.2 View of Hilum (root) of right lung.The hilum (highlighted in blue) is where thepulmonary vessels and bronchi enter through each lung.Thepleuraeare membranes that cover the surface of the lung and the cavity surrounding the lungs.Thevisceral pleuradirectly covers the lungs, and theparietal pleuracovers the surfacessurrounding the lungs: the rib cage, diaphragm, and mediastinum. The space that is formed betweenthe pleurae is called thepleural spaceor cavity. Normally, this space is empty except for a scantamount of fluid. However, in the diseased state, this cavity can fill with air or fluids. The pleuraereduce friction and provide a negative pressure environment needed for lung inflation. The pleuraealso help to pull the lungs open with the chest wall during inhalation.The anatomical organization of the respiratory system allows the respiratory system to perform threemain functions: 1) air conduction, 2) air filtration, and 3) exchange of gases. This third step is alsocalledrespiration. The respiratory system also has roles in vocalizations, the sense of smell, andthe body’s pH regulation. The body’s pH regulation is discussed further in Anatomy and PhysiologyII. Carbon dioxide forms carbonic acid, which must be buffered with bicarbonate ions.