Respiratory System By Dr Nassar Ayoub Associate Prof. of Anatomy The respiratory system is made up of the organs involved in the interchanges of gases, and consists of the: Nose, Pharynx , larynx , trachea, bronchi & lungs 1- The upper respiratory tract includes : Nose Pharynx Larynx 2- The lower respiratory tract includes : Trachea Bronchi Lungs Alveoli Nasal Cavity Nose It extends from the nostrils in front to the posterior nasal apertures apertures behind, where the nose opens into the nasopharynx. The The nasal cavity is divided into right and left halves by the nasal nasal septum. Walls of the Nasal Cavity Each half of the nasal cavity has a floor, a roof, a lateral wall, and a a medial or septal wall. Floor Maxillary bone and horizontal plate of the palatine bone (hard palate palate and soft palat) Roof Formed by nasal and frontal bones, in the middle by the cribriform cribriform plate of the ethmoid and posteriorly by the body of the the sphenoid. Lateral Wall The lateral wall has three projections of bone called the superior, middle, and inferior nasal conchae .The space space below each concha is called a meatus Medial Wall The medial wall is formed by the nasal septum. The upper part is formed by the vertical plate of the ethmoid and ethmoid and the vomer. The anterior part is formed by the septal cartilage Copyright 2009, John Wiley & Sons, Inc. Pharynx Starts at internal nares and extends to cricoid cartilage of larynx It surrounded by skeletal muscles which assists in deglutition - It contains lymphoid tissues which protect respiratory passage from infection(adenoid &tonsils) -It divided into 3 anatomical regions Nasopharynx Oropharynx Laryngopharynx -Eustachian tube connect nasopharynx with middle ear Functions of the pharynx 1-Passageway for air and food 2-Resonating chamber 3-Houses tonsils Eustachian tube The Larynx Is protective sphincter at the inlet of the air passages and is responsible for voice production. Site: below the tongue and hyoid bone at the level of the C3-C6 being a little higher in women than men. It opens above into the laryngeal part of the pharynx, and below is continuous with the trachea. The framework of the larynx consist of four basic components: Cartilaginous skeleton Membrane and ligaments Muscle (extrinsic and intrinsic) Mucosal lining Larynx….. • Cartilaginous framework of the larynx is formed by nine cartilages, three unpaired and three paired. • Unaired Cartilages Thyroid Cricoid Epiglottis • Paired cartilages Arytenoid Cuneiform Corniculate Larynx….. • Musculocartilaginous structure of the larynx is lined with mucus membrane connected above with pharynx below with trachea. • Ligaments hold the larynx, hyoid bone and trachea together. • Larynx serves three important functions: Protection of lower airways, Respiration , Phonation (Voice production). The Trachea - Beginning: It begins as a continuation of the larynx at the lower border of the cricoid cartilage at the level of level of the sixth cervical vertebra. - Course: It descends in the midline of the neck. In the thorax the trachea ends at the carina by dividing into into right and left principal (main) bronchi - End: at the level of the sternal angle (opposite the disc between the fourth and fifth thoracic vertebrae) vertebrae) T4-T5. -It is kept patent by the presence of U-shaped cartilaginous bar (rings) of hyaline cartilage which deficient posteriorly. - The Bronchi The trachea bifurcates behind the arch of the aorta into the right and left principal bronchi at the level of 4th thoracic vertebra. Lungs Site : The lungs are situated on each side of the chest cavity. They are therefore separated from each other by the heart and great vessels. It is covered with visceral &parietal pleura Shape: Apex, projects upward into the neck Base concave and sits on the diaphragm Surfaces: a convex costal surface, which corresponds to the concave chest wall Medial surface, which faces the heart. At about the middle of this surface is the hilum, a depression in which the bronchi, vessels, and nerves that form the root enter and leave the lung. Borders: The anterior border is thin and overlaps the heart; it is here on the left lung that the cardiac notch is found. Right Lung The right lung is slightly larger than the left and is divided by the oblique and horizontal fissures into into three lobes: the upper, middle, and lower lobes. lobes. The oblique fissure runs from the inferior border upward and backward across the medial and and costal surfaces until it cuts the posterior border. border. The horizontal fissure runs horizontally across the costal surface at the level of the fourth costal cartilage to meet the oblique fissure in the midaxillary line. The middle lobe is thus a small triangular lobe bounded by the horizontal and oblique Left Lung The left lung is divided by a similar oblique fissure into into two lobes: the upper and lower lobes. There is is no horizontal fissure in the left lung. What is the difference between Right and Left Lung?
