Respiratory System

• The anatomy of the respiratory system is discussed by Maria Rodea.
• bronchial tree refers to all branches of the respiratory system
• the bronchi are tubes that branch off from the trachea into the lungs
• the trachea is the windpipe
• the trachea connects the larynx to the bronchi, which are two tubes that branch off from it
• The respiratory region of the nasal cavity is larger and inferior, and is lined with pseudostratified ciliated columnar epithelium with numerous goblet cells.
• The olfactory region of the nasal cavity is smaller and superior, and includes the nasal vestibule, which is the anterior portion of the nasal cavity just inside the nostrils, surrounded by cartilage.
• The superior part of the olfactory region is surrounded by bone.
• The conchae are the superior, middle, and inferior nasal, which are the lateral wall of the nasal cavity.
• The meatuses are the superior, middle, and inferior nasal, which are a series of groovelike air passageways.
• The conchae and meatuses increase surface area in the internal nose and prevent dehydration.
• Inhaled air whirls and warms by blood capillaries in the nasal cavity.
• Mucus is secreted by Goblet cells to moisten air and trap dust particles.
• Drainage from the nasolacrimal ducts helps moisten hair, assisted by secretions from the paranasal sinuses.
• Cilia move the mucous and trapped dust particles toward the pharynx, where they can be swallowed or spit out for removal.
• The respiratory region of the nasal cavity contains olfactory receptor cells, supporting cells, and basal cells, which lie near the superior nasal conchae and adjacent septum.
• Goblet cells contain cilia but no goblet cells.
• Rhinoplasty is a surgical procedure in which the shape of the external nose is altered.
• Oxygenated blood – aorta → left and right pulmonary artery Blood supply to lungs is dual – pulmonary arteries and bronchial arteries.
• The superior and inferior lobes of the lungs are separated by the horizontal fissure, which is only found in the right lung.
• The inferior part of the lungs separates the inferior from the middle lobe, which is bordered superiorly by the horizontal fissure.
• The right main bronchus supplies three lobar bronchi: superior, middle, and inferior.
• The left main bronchus supplies two lobar bronchi: superior and inferior.
• Each lung contains 10 segmental bronchi that supply bronchopulmonary segments and localize bronchial and pulmonary disorders for surgical removal.
• Lobules are small compartments in each bronchopulmonary segment, wrapped in elastic connective tissue, containing a lymphatic vessel, an arteriole, a venule, and a branch from a terminal bronchiole.
• Terminal bronchioles penetrate more deeply into the lungs, subdividing to alveolar ducts, which are simple squamous epithelium.
• Alveoli are cup-shaped outpouchings lined by simple squamous epithelium and supported by a thin elastic basement membrane.
• Alveolar sacs are two or more alveoli that share a common opening.
• Type I alveolar (squamous pulmonary epithelial) cells are simple squamous epithelial cells that line the alveolar wall and are the main sites of gas exchange.
• Type II alveolar cells are rounded or cuboidal epithelial cells with free surfaces containing microvilli that secrete alveolar fluid and keep the surface between cells and air moist.
• Alveolar macrophages are phagocytes that remove fine dust particles and other debris from alveolar spaces.
• Fibroblasts produce reticular and elastic fibers on the outer surface of alveoli.
• Lobule’s arteriole and venule disperse into a network of blood capillaries, a single layer of endothelial cells and basement membrane.
• The respiratory membrane consists of four layers: the alveolar wall, the epithelial basement membrane, the capillary basement membrane, and the capillary endothelium.
• The blood supply to the lungs consists of two sets of arteries: pulmonary arteries and bronchial arteries.
• The ateral diameters of the chest cavity are 25% of the air that enters the lungs in normal breathing.
• Intrapleural pressure is the pressure between two pleural layers and is always atmospheric.
• Just before inhalation, intrapleural pressure is 4mmHg below atmospheric pressure (756 mmHg).
• During inhalation, the size of the thoracic cavity increases, causing intrapleural pressure to decrease to 754mmHg.
• During exhalation, the volume of the lungs increases, causing alveolar pressure to drop from 760 to 758mmHg.