5_Respiratory System.pptx

Respiratory System Chapter 20, Human Anatomy (LibreTexts) "Respiratory System" by Theresa Knott is licensed under CC BY-SA 2.5 Functions of the Respiratory System I • Ventilation: conduction of air through inhalation (inspiration) and exhalation (expiration) • Gas exchange (respiration) • Pulmona...

Respiratory System Chapter 20, Human Anatomy (LibreTexts) "Respiratory System" by Theresa Knott is licensed under CC BY-SA 2.5 Functions of the Respiratory System I • Ventilation: conduction of air through inhalation (inspiration) and exhalation (expiration) • Gas exchange (respiration) • Pulmonary: exchange of gases between alveoli and blood • Tissue: exchange of gases between blood and cells of the body tissues • Made possible by capillaries. Oxygen is needed in the cell to produce ATP and the waste product is carbon dioxide. Functions of the Respiratory System II • Gas conditioning • Warming of air through blood vessels in nasal cavity • Humidifying and cleansing of particulates • Twisted pathways in nasal cavity and paranasal sinuses facilitate gas conditioning • Sound production by moving air through the larynx • Olfaction • Defense against pathogens using anatomical features and also mucus and lysozyme secreted by cells Functional Organization Name Major Structures Function Conducting Zone Nose/Mouth, Pharynx, Larynx, Trachea, Bronchi, Bronchioles Deliver clean, warm, moistened air to Respiratory Zone Respiratory Zone Respiratory bronchioles, alveoli Gas Exchange Anatomical Organization Name Major Structures Upper respiratory tract Nose/Mouth, Pharynx Lower respiratory tract Larynx, Trachea, Bronchi, Bronchioles, Alveoli Major Respiratory Structures "Major Respiratory Organs" by OpenStax is licensed under CC BY 3.0 Upper: Nasal Cavity • External naris (nostril) is opening to nasal cavity. • Vestibule is anterior region of nasal cavity. • Lined with coarse hairs called vibrissae that help trap larger particles • Nasal cavity includes nasal conchae (“turbinate bones”) that form the lateral wall for each cavity and condition the air within the nasal cavity • Each concha has a nasal meatus (air passage) underneath it • Nasal septum divides right and left sides • Hard palate is bottom of nasal cavity • Nasal cavity is lined with respiratory epithelium made of pseudostratified ciliated columnar cells with goblet cells. • Superior part of nasal cavity contains olfactory epithelium where nerve endings of olfactory neurons reside. Nose "External Nose" by OpenStax is licensed under CC BY 3.0 Ciliated Pseudostratified Columnar Epithelium "Pseudostratified Epithelium" by OpenStax is licensed under CC BY 3.0 / Micrograph provided by the Regents of University of Michigan Medical School © 2012 Upper: Paranasal Sinuses • Paranasal sinuses decrease skull bone weight. • All sinuses communicate with nasal cavity through ducts • Named based on the bone they are housed into • • • • frontal sinus housed in frontal bone sphenoidal sinus housed in sphenoid bone ethmoidal sinus housed in ethmoid bone maxillary sinuses housed in maxillary bone • Paranasal sinuses are lined with pseudostratified ciliated columnar cells with goblet cells Upper Airway "Upper Airway" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work Upper: Pharynx • Pathway for food and air • Internal naris is opening to pharynx (= throat) which ends at esophagus and larynx • Pharynx is divided into 3 parts 1. Nasopharynx usually for air only: soft palate blocks food from mouth • lined with pseudostratified ciliated columnar epithelium 2. Oropharynx pathway for air and food • lined with non-keratinized stratified squamous epithelium 3. Laryngopharynx extends from hyoid bone to larynx and esophagus • lined with non-keratinized stratified squamous epithelium • Auditory tube from middle ear opens into nasopharynx • Soft palate lifts to block passage of food to nasal cavity during swallowing and helps vocalization • Tonsils provide first line of defense in immune system Divisions of the Pharynx "Divisions of the Pharynx" by OpenStax is licensed under CC BY 3.0 Lower: Larynx • The larynx is also called the voice box and represents the beginning of the lower respiratory tract. • Functions: • • • • • Passageway for air Prevents ingested materials from entering the respiratory tract Produces sound Assist in increasing pressure in abdominal cavity Participate in sneezing and coughing • Larynx is formed by 9 cartilages: epiglottis, thyroid cartilage and cricoid cartilage, arytenoid cartilages, corniculate cartilages and cuneiform cartilages Laryngeal cartilages • Larynx is made of cartilage and is held in place by ligaments and muscles • Thyroid cartilage is largest • Made of hyaline cartilage • front has v-shaped projection called laryngeal prominence • creates Adam’s apple • Epiglottis is anchored to the inner aspect of the thyroid cartilage • Made of elastic cartilage • Epiglottis flips down during swallowing to cover opening to trachea so that food passes down esophagus • Cricoid cartilage is ring-shaped cartilage • Made of hyaline cartilage • Forms the back part of the voice box and functions as an attachment site for muscles, cartilages, and ligaments involved in opening and closing the airway and in producing speech. The Larynx "The Larynx" by OpenStax is licensed under CC BY 3.0 Vestibular and Vocal Folds • Vestibular folds are false vocal cords • Minimal sound (e.g. death growl), made of mucous membrane • Protect vocal cords and help epiglottis • Vocal folds is are true vocal cords • Produce sounds when air passes between them • Avascular and white in color • Laryngitis: inflammation of the larynx, usually resulting in loss or coarse voice. Glottis "Cartilages of the Larynx" by OpenStax is licensed under CC BY 3.0 Lower: Trachea • Trachea = windpipe, main passageway for air • Kept open by tracheal cartilage rings which are Cshaped and connected by anular ligaments • Open ends of tracheal cartilage rings connected by trachealis muscle and elastic, ligamentous membrane which pushes against trachea during swallowing and contracts during coughing (decreases diameter of trachea, increases speed of airflow) • Trachea is anterior to esophagus • Lined with pseudostratified ciliated columnar epithelium Trachea Image credit: "Trachea" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work/Micrograph provided by the Regents of University of Michigan Medical School © 2012 Lower: Bronchial Tree • Trachea splits at sternal angle into left and right primary (or main) bronchi • Each main bronchus divides into secondary (lobar) bronchi • Lobar bronchi divide into tertiary (segmental) bronchi • Smaller bronchi branch into bronchioles • Terminal bronchioles are end of conducting pathway and branch into respiratory bronchioles • Respiratory bronchioles branch into alveolar ducts • Bronchioles are lined with simple columnar or cuboidal epithelium with no cartilage in walls but smooth muscle around walls • Smooth muscle contraction leads to bronchoconstriction (decrease in the diameter of the bronchioles) while smooth muscle relaxation leads to bronchodilation (increase in the diameter of the bronchioles). Bronchial Tree Image “Bronchial Tree" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work Structures of the Bronchial Tree Structure Description Trachea Delivers air through the mediastinum to the main bronchi Main (primary) Bronchus Branch from trachea to deliver air to each lung Lobar (secondary) Bronchus Branch from main bronchi to deliver air to each lobe Segmental (tertiary) Bronchus Branch from lobar bronchi to deliver air to each bronchopulmonary segment Bronchioles Branch from segmental bronchi to deliver air to the respiratory zone within a bronchopulmonary segment Lower: Alveoli • Alveolar ducts end with dilated alveolar sac that contains small, saccular out-pockets called alveoli. • Each alveolus is ¼ to ½ mm diameter with thin wall promotes gas diffusion • Alveolar pores are holes between adjacent alveoli to promote further gas diffusion • Pulmonary capillaries run between alveoli • Alveoli are lined with simple squamous epithelium Alveoli Image "The Respiratory Zone" by OpenStax is licensed under CC BY 3.0 Respiratory Membrane • Alveolar wall is mainly formed from two types of cells: • Alveolar type I cells: Abundant simple squamous epithelial cells promote rapid diffusion of gases • Alveolar type II cells: Almost cuboidal in shape and produce pulmonary surfactant, which decreases surface tension within alveolus and prevents its collapse • Alveolar macrophages (dust cells) engulf microorganisms and particulates in alveolus • The respiratory membrane is the thin wall between the alveoli and the pulmonary capillaries and consists of: • Plasma membrane of the type I alveolar cell • Plasma membrane of the capillary cell • Fused basement membrane of both cells • Oxygen diffuses from the alveoli to the capillaries, while carbon dioxide diffuses from capillaries to alveoli Respiratory Membrane Image "Structures of the Respiratory Zone" by OpenStax is licensed under CC BY 3.0 / Micrograph provided by the Regents of University of Michigan Medical School © 2012 Lungs • Left lung is smaller than right lung to provide space for the heart • Heart forms indent called cardiac notch • Right lung has three lobes (superior, middle and inferior) separated by horizontal and oblique fissures • Left lung has two lobes (superior and inferior) separated by oblique fissures • Bronchi, pulmonary vessels lymph vessels and nerve pass through hilum Gross Anatomy of the Lungs Apex Base "Gross Anatomy of the Lungs" by Julie Jenks is licensed under CC BY 4.0 / A derivative from the original work Pleura • Outside of lung and inside of thoracic wall are lined by serous membrane called pleura that is made by simple squamous epithelium • Outer surface is parietal pleura • Inner surface (contact with lung) is visceral pleura • Pleural cavity divides pleural layers, has thin layer of fluid • Pleura keeps lungs stretched and attached to the walls of thoracic cavity Parietal and Visceral Pleurae of the Lungs "The Lung Pleurae" by OpenStax is licensed under CC BY 3.0 Pneumothorax "Blausen 0742 Pneumothorax" by Bruce Blaus Blausen.com staff, Medical gallery of Blausen Medical is licensed under CC BY 3.0 Clinical Anatomy: COPD and Emphysema • As we age, the lungs become less elastic, thus breathing becomes less efficient. Due to pollution, particulate matter can accumulate in the lungs, resulting in obstruction. • Chronic obstructive pulmonary disease (COPD) may occur due to exposure to pollutants, but is most commonly associated with tobacco smoke. • These diseases decrease ventilation of the lungs, meaning the ability to bring an entirely new volume of fresh air into the lungs with each breath. This decreases the amount of oxygen exchange that can occur. • Emphysema, another disease associated with tobacco smoke, is a breakdown of the alveolar walls. This decreases alveolar surface area, decreasing the amount of oxygen exchange that can occur along the respiratory surface. Chronic Obstructive Pulmonary Disorder (COPD) "COPD_2010Side" by National Heart Lung and Blood Institute is in the Public Domain Clinical Anatomy: Lung Cancer • Lung cancer is one of the most common types of cancer, and one of the most preventable, as most cases are linked to tobacco smoke. Cigarettes contain carcinogens, or chemicals that lead to cancer-causing genetic mutations. • Lung cancer can lead to obstruction of the lungs, but is also highly metastatic, meaning very likely to spread, because of its access to the vast blood supply within the lungs. It is often difficult to diagnose until it has progressed significantly. Clinical Anatomy: COVID-19