Respiratory System 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: Iden-fy and explore the various components that go to make up the respiratory system. Iden-fy the histol...

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: Iden-fy and explore the various components that go to make up the respiratory system. Iden-fy the histological and physiological aspects of the various parts of the respiratory system. Demonstrate an understanding of the func-on 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 -ssues and cells, excre-ng the excess and waste. Oxygen is our “ food” and Carbon dioxide is our “waste” What is the deGniDon of RespiraDon? The exchange of oxygen and carbon dioxide between the atmosphere and the body cells, including inspiraDon and expiraDon, diFusion 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 & Dic-onary of Medicine, Nursing & Allied Health Sixth Edi-on 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 car-lage) The nasal cavity is par--oned from the oral cavity directly below it by the palate What is the funcDon of the nose and nasal hairs? Due to dense Traps par-cles, 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 HumidiGcaDon A liOle more about our noses! There is a rich blood supply Innerva-on 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. En-re mucosa of the nasal fossae is covered by mucus, secreted by ciliated columnar epithelium which contains secre-ng goblet cells Also houses our sense of smell & contributes greatly to taste sensa-on through its posterior communica-on with the mouth The Palates: Hard palate: Forms `oor of nasal cavity Separates nasal and oral cavi-es SoR 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 conven-onally divided into three sec-ons: 1. Nasopharynx 2. Oropharynx 3. Laryngopharynx It is also important in vocaliza-on Pharynx The func-on of the pharynx is to transfer food from the mouth to the oesophagus and to warm, moisten and clter air before it moves into the trachea. The pharynx is a part of both the diges-ve and respiratory systems Nasopharynx 2 to 3 cm wide and 3 to 4 cm long Is the space above the sof palate at the back of the nose and connects the nose to the mouth, which allows a person to breathe through the nose The sof palate separates the nasopharynx from the oropharynx It contains adenoid -ssue, which cghts infec-on, and the openings to the Eustachian tubes, which lead to the ears. It provides a major drainage path for lympha-c `uids 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, poten-ally with fatal consequences Laryngopharynx Lined by stra-ced squamous epithelium. The func-on 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 carDlage (Adam's apple) – hyaline carDlage 2. The Cricoid carDlage – hyaline carDlage 3. The Epiglo\s – elasDc carDlage Larynx and surrounding structures Lower Respiratory Tract: Bronchi ( sing. Bronchus) Conducts air into the lungs Right and lef Bronchus branch into smaller secondary and ter-ary branches which then branch into smaller tubes known as bronchioles No gas exchange takes place in the Bronchi Contains progressively less car-lage and more smooth muscle Bronchioles No car-lage present: smooth muscle dominates Progressing down the bronchioles, the muscle and connec-ve -ssue begin to disappear, and a single layer of epithelial cells remains: alveoli Func-on 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 crst 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 ofen referred to as the dead space because no air exchange takes place in these passages. The Bronchioles are -ny: 0.3 – 1mm in diameter. The walls of the Bronchioles are lined with cnger like projec-ons known as cilia. The func-on of the cilia is to remove debris and microbes CoFee Dme! 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 diiuses through a single cell in an alveolus, followed by a single cell in a capillary to enter the bloodstream At the same -me, CO2 is released from the capillary to the alveoli and then exhaled. Pleural CaviDes & Membranes The Pleural cavity is a `uid-clled space between the 2 pulmonary pleurae. The outer Pleura (parietal) is ajached 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 poten-al space because the 2 Pleurae adhere to each other through a serous thin clm (in normal condi-ons) 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 cssures. The right lung consists of 3 lobes: Superior, Middle and Inferior. The lef 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 ter-ary 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 mul-ple branches. An interlobular septum is a wall composed of connec-ve -ssue, separa-ng The cardiac notch: the indentaDon seen on the leR 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 addi-on, innerva-on by the parasympathe-c and sympathe-c nervous system provides a level of control through dila-on and constric-on of the airway.  The major func-on of the lungs is to perform gaseous exchange. This requires blood from the pulmonary circulaDon. This blood supply contains deoxygenated blood, travels to the lungs where erythrocytes pick up the O2 to transport to body -ssues. The pulmonary artery carries deoxygenated blood to the alveoli, this artery branches mul-ple -mes 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 -ny 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 crea-ng the respiratory membrane. Once the blood is oxygenated, it drains from the alveoli, by way of mul-ple pulmonary veins, which exit the lungs through the hilum. The hilum is a wedge-shaped area on the central por-on of each lung The Hilum are where the bronchi, arteries, veins and nerves enter and exit the lungs. Both right and lef Hilum are similar in size, but the lef hilum usually is slightly higher in the chest than the right. It is interes-ng to note that due to their posi-on it can be dikcult 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 ajached to the Sternum by costal car-lage Of the remaining 5, 3 have costal car-lage connected to the car-lage above and the last 2 `oa-ng ribs are connected by their car-lage to muscle in the abdominal wall. InspiraDon & ExpiraDon During InhalaDon 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 cll with air due to the nega-ve pressure created by the extra space As air clls the lungs, gases are exchanged and it’s -me to exhale During ExhalaDon: 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 RespiraDon….. These do not ac-vely play a part in breathing but are considered accessory as they help in eleva-ng the rib cage. They are the sternocleidomastoid and the scalene. Some other neck muscles are also considered as accessory muscles of respira-on. We have Gnished! Thank you for your ajen-on. Please feel free to contact me should you have any ques-ons [email protected]