Johny's A&P structure and function of respiratory system
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The respiratory system allows for breathing and gas exchange. It is divided into the upper and lower respiratory tract. The upper tract includes the nose, mouth, larynx, and pharynx. The lower tract includes the trachea, bronchi, and lungs. The lungs contain bronchioles and alveoli where gas exchange occurs. During breathing, the diaphragm and intercostal muscles work to expand and contract the lungs and chest cavity to inhale and exhale air.
Johny's A&P structure and function of respiratory system
- 1. The Respiratorysystem Prepared By: Mr. Johny Kutty Joseph Asstt. Professor, SMVDCoN
- 2. The respiratory system is the set of organs that allows a person to breathe and exchange oxygen and carbon dioxide throughout the body. The integrated system of organs involved in the intake and exchange of oxygen and carbon dioxide between the body and the environment and including the nasal passages, larynx, trachea, bronchial tubes, and lungs. The respiratory system performs two major tasks such as external respiration (exchanging air between the body and the outside environment) and internal respiration (exchange of air from cell.
- 4. The respiratory system is divided into upper respiratory tracts and lower respiratory tracts. The organs of upper respiratory tracts are located outside the thorax whereas the lower are located within it. The upper respiratory tract is composed of nose, nasopharynx, oropharynx, laryngipharynx, and larynx. The lower respiratory tracts consist of trachea, bronchial tree and lungs.
- 5. Nose The nose has two structures/ nares such as internal and external nares. The external part is protruding from the face and is divided into two halves by the nasal septum. Contains the paranasal sinuses where air is warmed. Paranasal sinuses are a group of paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoidal sinuses are behind the eyes. The Nares also contains cilia which is responsible for filtering out foreign bodies.
- 6. Paranasal air sinuses The maxillary sinuses: under the eyes; frontal sinuses: above the eyes; the ethmoidal sinuses : between the eyes and the sphenoidal sinuses : behind the eyes. The functions are decreasing weight of skull, increasing resonance of the voice, Humidification and heating air and immunological defense.
- 7. Nose • The internal nose lies over the roof of the mouth. The palate separates mouth and nose. • The roof of nose is separated from the cranial cavity by a portion of ethmoid bone called cribiform plate. The olfactory nerves enter through opening on cribiform plate.
- 8. Nasal Mucosa • The air pass further to nasal mucous membrane. This is made of ciliated columnar epithelium rich in goblet cells. The olfactory epithelium which contains olfactory nerves. This lining is further extended to bronchial tree. • In addition to olfactory neurons the nasal mucosa is also imbedded with a structure called VNO (Vomero Nasal Organ). This helps in sensing sex signaling chemicals called pheromones. • Filtration , warmth, moistened, and chemical screening is done by nose and paranasal air sinuses. • The hollow sinus also helps in decreasing the weight of the skull.
- 9. Pharynx • The pharynx (plural: pharyng es) is the part of the throat that is behind the mouth and nasal cavity and above the oesophagus and the larynx. • The pharynx has three anatomical divisions. • The nasopharynx, is the upper portion of the pharynx extends from the base of the skull to the upper surface of the soft palate.
- 10. Pharynx • It includes the space between the internal nares and the soft palate and lies above the oral cavity. The auditory tube is connected to middle ear through the pharyngeal opening of the auditory tube. The opening and closing of the auditory tubes serves to equalize the barometric pressure in the middle ear with that of the ambient atmosphere.
- 11. Pharynx • The pharyngeal tonsils are located in nasopharynx. • The oropharynx lies behind the oral cavity, extending from the uvula to the level of the hyoid bone. Uvula prevents the entry of food into nasal cavity. The palatine tonsils are located in oropharynx.
- 12. Pharynx • The laryngopharynx, also known as hypopharynx, is the caudal part of the pharynx; it is the part of the throat that connects to the esophagus. It lies inferior to the epiglottis and extends to the location where this common pathway diverges into the respiratory (larynx) and digestive (esophagus) pathways. • The pharynx serve as common pathway for the respiratory and digestive tracts.
- 13. Larynx Voice box is a short, somewhat cylindrical airway starts from the root of the tongue and ends in the trachea. Located between third and sixth cervical vertebrae. Prevents swallowed materials from entering the lower respiratory tract. Conducts air into the lower respiratory tract and Produces sounds.
- 14. Larynx It is triangle shaped It consists of cartilages and attached to one another by elastic muscles. It is lined by ciliated mucous membrane. The mucous membrane forms folds laterally and inferiorly which is called ac vocal folds/cords. Nine cartilages forms larynx.
- 15. Larynx Three Thyroid cartilages: largest cartilage of larynx, its gives the triangular shape. The anterior laryngeal eminence formed by thyroid cartilage is called Adam’s Apple. It is larger in men (fat deposition) and lesser in women. The cricoid cartilages: they are singe paired structures such as Arytenoid cartilage (Pyramid shaped & attached to vocal folds), corniculate and cuneiform cartilages.
- 16. Larynx One epiglottis: a small leaf shaped cartilage attached to thyroid cartilage and has free superior border and it prevents the entry of food and liquids into trachea. Larynx has two types of muscles such as intrinsic muscles (they originate and insert in larynx. They regulate length, tension and shape of laryngeal inlet.) and extrinsic muscles( this helps in the movement of larynx such as in respiration vocalization and swallowing). Larynx helps in purification of air from dust, humidification, warming. It prevents the food and liquid entry to lungs. It is the voice box. The vibration of vocal folds creates voice.
- 17. Trachea The trachea is a flexible tube also called windpipe. It is 11cm long and extend from larynx to primary bronchi. Extends through the mediastinum and lies anterior to the esophagus and inferior to the larynx. Cartilage rings reinforce and provide rigidity to the tracheal wall to ensure that the trachea remains open at all times.
- 18. Trachea level of the sternal angle, the trachea bifurcates into two smaller tubes, called the right and left primary bronchi. Each primary bronchus projects laterally toward each lung. The trachea is lined by respiratory mucosa consists of ciliated columnar epithelium.
- 19. Bronchi and Alveoli The trachea divides into two primary bronchi. Each primary bronchus divides into secondary and tertiary bronchi. It further divides into small bronchioles. This together called as bronchial tree. The right primary bronchus divides into three secondary bronchi such as to supply three lobes. The left branch divides into two secondary bronchi.
- 20. Bronchi and Alveoli The terminal bronchioles are microscopic. The terminal bronchioles further divide into alveolar ducts which ends in alveoli. 300 million alveoli are estimated to be in the lungs. The alveoli has a sponge like structure and are the primary gas exchange structures.
- 21. Bronchi and Alveoli Alveolus is extremely thin walled structure which is in contact with blood capillaries and gas exchange takes place across the respiratory membrane. Each alveoli is enveloped with capillary. Thus the purified air enters blood stream.
- 22. Lungs The lungs are cone shaped organs large enough to fill the pleural portion of thorax. They extend from clavicle to diaphragm. The medial surface of each lung is concave to occupy the organs of mediastinum. The root of lung consist of pulmonary vessels and bronchi which is connected by a connective tissue and it enters medially through the space called hilum.
- 23. Functions of Lungs The left lung has a concavity called cardiac notch where the apex of the heart lies. Air distribution to the alveoli is the function of the tubes of the bronchial tree. Gas exchange between air and blood is the joint function of the capillaries and alveoli. They have enormous surface area which is called as respiratory membrane.
- 24. Lungs Each lung is divided into lobes by fissure. The left lung is divided into superior and inferior lobes. The right lung is divided into superior, middle and inferior lobes. The lobes are further divided into broncho-pulmonary segments.
- 25. Pleura The outer surface of each lung and the adjacent internal thoracic wall are lined by a serous membrane called pleura. The outer surface of each lung is tightly covered by the visceral pleura. while the internal thoracic walls, the lateral surfaces of the mediastinum, and the superior surface of the diaphragm are lined by the parietal pleura. The parietal and visceral pleural layers are continuous at the hilus of each lung The potential space between the serous membrane layers is a pleural cavity.
- 26. Pleura The pleural membranes produce a thin, serous pleural fluid that circulates in the pleural cavity and acts as a lubricant, ensuring minimal friction during breathing. Pleural fluid is a serous fluid produced by the serous membrane covering normal pleurae. Most fluid is produced by the parietal circulation (intercostal arteries) via bulk flow and reabsorbed by the lymphatic system.
- 27. Clinical Implications Rhinitis: Inflammation of nasal mucosa Pharyngitis: Inflammation of Pharynx. Laryngitis: Inflammation of Larynx. Tonsilitis: Inflammation of tonsils: tonsillectomy Sinusistis: Inflammation of air sinus Deviated nasal septum: obstruction due to anatomical defect: septoplasty. Bronchitis: Inflammation of Bronchi. Pneumonia: Inflammation of lung paranchyma. Tuberculosis: Infection by bacteria. Lung Cancer: malignancy: Lobectomy
- 28. Muscles of Respiration The muscles of respiration are those muscles that contribute to inhalation and exhalation by aiding in the expansion and contraction of the thoracic cavity. The diaphragm and, to a lesser extent, the intercostal muscles drive respiration during quiet breathing. Additional 'accessory muscles of respiration' are typically only used under conditions of high metabolic demand (e.g. exercise) or respiratory dysfunction (e.g. an asthma attack).
- 29. Diaphragm • It is the major muscle responsible for breathing. • It is a thin, dome-shaped muscle that separates the abdominal cavity from the thoracic cavity. • During inhalation, the diaphragm contracts, so that it's centre moves downward and its edges move upward. This compresses the abdominal cavity, and expands thoracic cavity. This draws air into the lungs. • When the diaphragm relaxes, elastic recoil of the thoracic wall causes the thoracic cavity to contract, forcing air out of the lungs. • The diaphragm is also involved in non-respiratory functions, helping to expel vomit, feces, and urine from the body by increasing intra-abdominal pressure.
- 30. Intercostal Muscles • Along with the diaphragm, the intercostal muscles are one of the most important groups of respiratory muscles. • These muscles are attached between the ribs and are important in manipulating the width of the rib cage. • External intercostal muscles aid in quiet and forced inhalation. • Internal intercostal muscles aid in forced expiration. • The innermost intercostal muscle is a layer of intercostal muscles deep to the plane that contains the intercostal nerves and intercostal vessels. It does not have a direct role in respiration.
- 31. Accessory Muscles • "Accessory muscles" refers to muscles that assist, but do not play a primary role, in breathing. • The sternocleidomastoid (a paired muscle in the superficial layers of the side of the neck) helps in respiration. • The scalene muscles (group of three pairs of muscles in the lateral neck, namely the anterior scalene, middle scalene, and posterior scalene) also help in respiration. • They are typically considered accessory muscles of breathing. • Other muscles of neck and chest also support breathing.