The Respiratory System 2023 PDF

The Respiratory System Module: Biomedical Science Lecturer: Rhona Mann GDC Learning Outcomes 1.1 ,1.1.1 , 1.1.3 , 1.1.5 , 1.1.6 , 1.1.11 , 1.10.1 , 1.10.3 Intended Learning Outcomes: Identify and explore the various components that go to make up the respiratory system. Identify the hist...

The Respiratory System Module: Biomedical Science Lecturer: Rhona Mann GDC Learning Outcomes 1.1 ,1.1.1 , 1.1.3 , 1.1.5 , 1.1.6 , 1.1.11 , 1.10.1 , 1.10.3 Intended Learning Outcomes: Identify and explore the various components that go to make up the respiratory system. Identify the histological and physiological aspects of the various parts of the respiratory system. Demonstrate an understanding of the function of each component within the system In basic terms “What is the Respiratory system?” It’s our Breathing Equipment! We inhale and exhale gases that circulate around our body tissues and cells, excreting the excess and waste. Oxygen is our “ food” and Carbon dioxide is our “waste” What is the definition of Respiration? The exchange of oxygen and carbon dioxide between the atmosphere and the body cells, including inspiration and expiration, diffusion of oxygen from the pulmonary alveoli to the blood and carbon dioxide from the blood to the alveoli, and the transport of oxygen to and carbon dioxide from the body cells. Miller-Keane Encyclopedia & Dictionary of Medicine, Nursing & Allied Health Sixth Edition Structure of the Respiratory System: Upper The Nasal cavity The Pharynx The Larynx The Trachea Lower The Bronchi/Bronchioles The Lungs The Pleura The Diaphragm Ribs and Intercostal Muscles Upper Respiratory System TRACHEA The Nose and Nasal Cavity: Only part of the respiratory system that is visible externally Route for air entry into the respiratory system Air is drawn in via the nostrils and enters the large nasal cavity, which is divided into two by the nasal septum (hyaline cartilage) The nasal cavity is partitioned from the oral cavity directly below it by the palate What is the function of the nose and nasal hairs? Due to dense Traps particles, vascularity dust adheres to Nose bleed = large mucus – mucus blood loss prevents drying Filtering & Warming cleaning Air travels over moist mucosa Becomes saturated with water Humidification A little more about our noses! There is a rich blood supply Innervation of the nasal cavity is responsible for the sense of smell via the olfactory nerve Air passing through the nasal cavity is warmed or cooled to within 1 degree of body temperature. Entire mucosa of the nasal fossae is covered by mucus, secreted by ciliated columnar epithelium which contains secreting goblet cells Also houses our sense of smell & contributes greatly to taste sensation through its posterior communication with the mouth The Palates: Hard palate: Forms floor of nasal cavity Separates nasal and oral cavities Soft palate: Extends posterior to hard palate Divides superior nasopharynx from lower pharynx The Pharynx: Makes up the part of the throat situated immediately behind the nasal cavity Behind the mouth & above the oesophagus & larynx The human pharynx is conventionally divided into three sections: 1. Nasopharynx 2. Oropharynx 3. Laryngopharynx It is also important in vocalization Pharynx The function of the pharynx is to transfer food from the mouth to the oesophagus and to warm, moisten and filter air before it moves into the trachea. The pharynx is a part of both the digestive and respiratory systems Nasopharynx 2 to 3 cm wide and 3 to 4 cm long Is the space above the soft palate at the back of the nose and connects the nose to the mouth, which allows a person to breathe through the nose The soft palate separates the nasopharynx from the oropharynx It contains adenoid tissue, which fights infection, and the openings to the Eustachian tubes, which lead to the ears. It provides a major drainage path for lymphatic fluids and generally drains into the throat, nose or ears Oropharynx The oropharynx accepts air from the nasopharynx and passes it to the laryngeal pharynx. It also accepts food from the mouth and passes it to the oesophagus It is very important that the oropharynx and associated structures prevent food or liquids from entering the lungs. If this happens, choking may ensue, potentially with fatal consequences Laryngopharynx Lined by stratified squamous epithelium. The function is to pass food and air It works as a passage for food and air During swallowing, the entry of air temporarily stops allowing the food to pass safely to the oesophagus. This prevents the food from entering our respiratory tract and from choking the trachea (windpipe) Larynx Allows air to pass through it while keeping food and drink from blocking the airway. The larynx is also the body’s “voice box” as it contains the vocal folds that produce the sounds of speech and singing! Consists of: 1. The Thyroid cartilage (Adam's apple) – hyaline cartilage 2. The Cricoid cartilage – hyaline cartilage 3. The Epiglottis – elastic cartilage Larynx and surrounding structures Lower Respiratory Tract: Bronchi ( sing. Bronchus) Conducts air into the lungs Right and left Bronchus branch into smaller secondary and tertiary branches which then branch into smaller tubes known as bronchioles No gas exchange takes place in the Bronchi Contains progressively less cartilage and more smooth muscle Bronchioles No cartilage present: smooth muscle dominates Progressing down the bronchioles, the muscle and connective tissue begin to disappear, and a single layer of epithelial cells remains: alveoli Function of the Bronchioles is to deliver air to the network of millions of alveoli. There are 3 types of bronchioles: Lobular (these are the passages that first enter the lungs) Terminal (smaller passages in each lung) Respiratory (leading on from terminal branches that lead to alveolar ducts) Cilia The lobular and terminal branches are often referred to as the dead space because no air exchange takes place in these passages. The Bronchioles are tiny: 0.3 – 1mm in diameter. The walls of the Bronchioles are lined with finger like projections known as cilia. The function of the cilia is to remove debris and microbes Coffee time! We will have a short break now of 30 minutes. During the break think about: How and where gaseous exchange takes place within the lungs Alveoli Millions of alveoli…. If stretched end to end they would cover a tennis court! Air exchange takes place here. Once O2 reaches the alveoli it diffuses through a single cell in an alveolus, followed by a single cell in a capillary to enter the bloodstream At the same time, CO2 is released from the capillary to the alveoli and then exhaled. Pleural Cavities & Membranes The Pleural cavity is a fluid-filled space between the 2 pulmonary pleurae. The outer Pleura (parietal) is attached to the chest (thoracic) wall. The inner Pleura (visceral) covers the lungs and adjoining structures including the blood vessels, bronchi and nerves. The Pleural Cavity is considered a potential space because the 2 Pleurae adhere to each other through a serous thin film (in normal conditions) The anatomy of the lungs  As you can see from these previous slides, the lungs consist of lobes that are separated from each other by fissures. The right lung consists of 3 lobes: Superior, Middle and Inferior. The left lung consists of 2 lobes: Superior and Inferior. The bronchopulmonary segment is a division of a lobe, and each lobe houses bronchopulmonary segments. Each segment receives air from its own tertiary bronchus and is supplied with blood by its own artery. A pulmonary lobule is a subdivision formed as the bronchi branch into bronchioles. Each lobule receives its own bronchiole that has multiple branches. An interlobular septum is a wall composed of connective tissue, separating The cardiac notch: the indentation seen on the left lung, allows space for the heart The blood supply to the lungs plays an important role in the gas exchange and serves as a transport system for gases throughout the body. In addition, innervation by the parasympathetic and sympathetic nervous system provides a level of control through dilation and constriction of the airway.  The major function of the lungs is to perform gaseous exchange. This requires blood from the pulmonary circulation. This blood supply contains deoxygenated blood, travels to the lungs where erythrocytes pick up the O2 to transport to body tissues. The pulmonary artery carries deoxygenated blood to the alveoli, this artery branches multiple times as it follows the bronchi, becoming smaller and smaller in diameter. One arteriole and one venule supply and drain one pulmonary lobule. As they near the alveoli, the pulmonary arteries become the pulmonary capillary network. Alveoli This capillary network consists of tiny vessels with very thin walls. This pulmonary capillary network branches and follows the bronchioles and the structure of the alveoli. At this point the capillary wall meets the alveolar wall creating the respiratory membrane. Once the blood is oxygenated, it drains from the alveoli, by way of multiple pulmonary veins, which exit the lungs through the hilum. The hilum is a wedge-shaped area on the central portion of each lung The Hilum are where the bronchi, arteries, veins and nerves enter and exit the lungs. Both right and left Hilum are similar in size, but the left hilum usually is slightly higher in the chest than the right. It is interesting to note that due to their position it can be difficult to visualize them on chest X rays. Further tests e.g CT scan are required to determine if a problem exists in the area. The Intercoastal Muscles Are a group of muscles that are situated in the ribs. There are 3 layers that assist in the breathing process: External : these sit outside the ribs Internal: these sit between the ribs Innermost: these sit inside the ribs They are innervated by the intercostal nerves, and blood supply is from the intercostal artery and vein. Thoracic (Rib) Cage…. Surrounds and protects the heart and lungs 12 Thoracic vertebrae, 24 ribs plus the sternum First 7 ribs are attached to the Sternum by costal cartilage Of the remaining 5, 3 have costal cartilage connected to the cartilage above and the last 2 floating ribs are connected by their cartilage to muscle in the abdominal wall. Inspiration & Expiration During Inhalation Diaphragm relaxes ,lungs expand The innermost intercostal muscles relax while the external intercostal muscles contract causing the chest cavity to expand. This expansion allows the lungs to fill with air due to the negative pressure created by the extra space As air fills the lungs, gases are exchanged and it’s time to exhale During Exhalation: Basically, we need to force air out so…… Chest cavity must become smaller. The diaphragm and the external intercostal muscles contract applying force to the base and sides of the lungs. The innermost intercostal muscles contract while the external intercostal muscles relax. The cavity contracts and air is forced out Accessory Muscles of Respiration….. These do not actively play a part in breathing but are considered accessory as they help in elevating the rib cage. They are the sternocleidomastoid and the scalene. Some other neck muscles are also considered as accessory muscles of respiration. We have finished! Thank you for your attention. Please feel free to contact me should you have any questions [email protected]