A&P 1 Module 22.1 General Anatomy of the Respiratory System●Gross anatomyis the study of the organs andstructures of the human body visible to thenaked eye.●Lungs○When looking at the lungs from a grossanatomical perspective, the lungs arepaired and found in the chest cavity(Figure 2.1). Notice that the lungs arenot symmetrical.○The right lung has three lobes: superior,middle, and inferior. The left has twolobes: superior and inferior. Thisasymmetry is due the position of theheart, which is situated slightly to theleft of the median plane.○The hilum is known as the “root” of thelung. This is where the pulmonary vesselsand bronchi enter each lung (Figure 2.2).○Healthy lung tissue has a very lighttexture and is peachy/pink in color.■Figure 2.1 Anterior view: Grossanatomy of lungs.The right lung hasthree lobes (superior, middle,inferior) while the left lung hastwo lobes (superior, inferior). Theright and left lung both haveoblique fissures separating thelobes. The right lung also has a horizontal fissure separatingthe superior and middle lobes.■Figure 2.2 View of Hilum (root) of right lung.The hilum(highlighted in blue) is where the pulmonary vessels and bronchienter through each lung.○Thepleuraeare membranes that cover the surface of the lung and thecavity surrounding the lungs.■Thevisceral pleuradirectly covers the lungs, and theparietalpleuracovers the surfaces surrounding the lungs: the rib cage,diaphragm, and mediastinum.■The space that is formed between the pleurae is called thepleural spaceor cavity. Normally, this space is empty except fora scant amount of fluid.●However, in the diseased state, this cavity can fill withair or fluids.■The pleurae reduce friction and provide a negative pressureenvironment needed for lung inflation.■The pleurae also help to pull the lungs open with the chest wallduring inhalation.●The anatomical organization of the respiratory system allows the respiratorysystem to perform three main functions: 1) air conduction, 2) air
filtration, and 3) exchange of gases. This third step is also calledrespiration.○The respiratory system also has roles in vocalizations, the sense ofsmell, and the body’s pH regulation.○The body’s pH regulation is discussed further in Anatomy andPhysiology II.■Carbon dioxide forms carbonic acid, which must be buffered withbicarbonate ions.●The following outlines the major portions of the respiratory system:○Conducting portion■Nostril - nasal cavities■Pharynx: nasopharynx, oropharynx, laryngopharynx■Larynx■Trachea■Paired main (primary) bronchi (bronchi is the plural form ofbronchus)■Bronchioles: secondary and tertiary○Filtration portion■Nostrils: hairs, cilia, and mucus producing goblet cells■Trachea and bronchi: cilia and mucus producing goblet cells○Respiratory portion■Respiratory bronchioles■Alveolar ducts■Alveolar sacs■Alveoli●The human respiratory system includes all structures that conduct air to andfrom the lungs.