Respiratory Anatomy PDF

Respiratory System Respiratory system Respiratory system : Structurally, consists of two parts: 1. The upper respiratory system includes the nose, nasal cavity, pharynx and associated structures. 2. The lower respiratory system includes the larynx, trachea, bronchi and lungs Dr. Ali Mohammed Respira...

Respiratory System Respiratory system Respiratory system : Structurally, consists of two parts: 1. The upper respiratory system includes the nose, nasal cavity, pharynx and associated structures. 2. The lower respiratory system includes the larynx, trachea, bronchi and lungs Dr. Ali Mohammed Respiratory system Respiratory system functionally 1. The conducting zone consists of a series of interconnecting cavities and tubes both outside and within the lungs. These include the nose, nasal cavity, pharynx ,larynx, trachea, bronchi, bronchioles, and terminal bronchioles. Function is to filter, warm, and moisten air and conduct it into the lungs 2. The respiratory zone consists of tubes and tissues within the lungs where gas exchange occurs. These include the respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli. (Gas exchange occur in these zone) Dr. Ali Mohammed Respiratory system Respiratory mucosa : It is a layer of pseudostratified ciliated columnar epithelial cells that secrete mucus. Found in nose, sinuses, pharynx, larynx and trachea Mucus can trap contaminants Cilia move mucus up towards mouth Dr. Ali Mohammed Respiratory system Nose Nasal cavity-within and posterior to external nose Divided by midline nasal septum Posterior nasal apertures (conchae) open into nasopharynx Roof-ethmoid and sphenoid bones Floor–hard (bone) and soft palates (muscle) Nasal vestibule-nasal cavity superior to nostrils Vibrissae (hairs) filter coarse particles from inspired air Dr. Ali Mohammed Respiratory system Paranasal sinuses : Four bones of the skull contain paired air spaces: 1-frontal, 2-ethmoidal, 3-sphenoidal, 4-maxillary. Add resonance to voice. Communicate with the nasal cavity by ducts Dr. Ali Mohammed Respiratory system Pharynx : Pharynx is divided into three regions : 1-Nasopharynx - uppermost portion 2-Oropharynx - middle portion 3-Laryngopharynx - lowermost portion Wall is composed of skeletal muscles and is lined with a mucous membrane. The muscles arranged in two layers, an outer circular layer and an inner longitudinal layer Dr. Ali Mohammed Respiratory system Dr. Ali Mohammed Respiratory system Nasopharynx : Posterior to the nasal cavity ,superior to the soft palate. Lateral walls of the nasopharynx connect to the auditory/eustachian tubes which open into middle ear. Only air passes through. Material from the oral cavity and oropharynx is typically blocked from entering the nasopharynx by the uvula of soft palate, which elevates when swallow. Posterior nasopharynx wall also houses pharyngeal tonsil ( the adenoids). Dr. Ali Mohammed Respiratory system Dr. Ali Mohammed Respiratory system Pharynx : Oropharnyx Two pairs of tonsils, the palatine tonsils and lingual tonsils are found in the oropharynx. Laryngopharynx or hypopharynx Inferior, narrowed region of the pharynx. Inferior end it opens into the esophagus (food tube) posteriorly and the larynx (voice box) anteriorly. Permits passage of both food and air. Dr. Ali Mohammed Larynx Respiratory system Larynx : Larynx or Voice box is a short, cylindrical airway ends in the trachea. It is about 5 cm long. It conducts air into the lower respiratory tract Produces sounds. Composed of nine pieces of cartilage ,held in place by ligaments and muscles. Except for the epiglottis, all cartilages are hyaline cartilages. Muscles of larynx: extrinsic muscles and intrinsic muscles. The extrinsic muscles of the larynx connect the cartilages to other structures in the throat. The intrinsic muscles connect the cartilages to one another. Dr. Ali Mohammed Respiratory system Cartilages of larynx : Nine C-rings of cartilage form a framework of the larynx. 3 unpaired , 3 paired 3 unpaired cartilages : Thyroid cartilage Cricoid cartilage Epiglottis 3 paired cartilages : Arytenoid Cuneiform Corniculate cartilages Dr. Ali Mohammed Respiratory system Larynx : Thyroid cartilage – (Adam’s apple) consists of two fused plates form the anterior wall of the larynx and give it a triangular shape. The ligament that connects the thyroid cartilage to the hyoid bone is called the thyrohyoid membrane. Dr. Ali Mohammed Respiratory system Vocal cords : The mucous membrane of the larynx forms two pairs of folds. A superior pair called the ventricular folds (false vocal cords) space between them called the rima vestibuli Inferior pair called the vocal folds (true vocal cords). Glottis – a triangular slit opening containing between the true vocal cords. Its closure helps to prevent food or liquid from entering the trachea. Dr. Ali Mohammed Respiratory system Dr. Ali Mohammed Respiratory system Dr. Ali Mohammed Trachea Respiratory system Trachea Flexible cylindrical tube , Size is 4 – 5 in long & 1 in diameter, also called windpipe. Extends through the mediastinum and lies anterior to the esophagus and inferior to the larynx. Anterior and lateral walls of the trachea supported by 15 to 20 C-shaped tracheal cartilages. Cartilage provide rigidity to the tracheal wall Posterior part of tube lined by trachealis muscle Dr. Ali Mohammed Respiratory system At the level of the sternal angle, the trachea divides into two smaller tubes, called the right and left primary bronchi. The inferior tracheal cartilage separates the primary bronchi and forms an internal ridge called the carina. Incomplete rings of hyaline cartilage support the walls of the primary bronchi to ensure that they remain open. Primary bronchi supply each lung. Dr. Ali Mohammed Respiratory system Dr. Ali Mohammed Respiratory system Bronchial Tree : Secondary bronchi supply each lobe of the lungs (3 right + 2 left). Tertiary bronchi splits into successive sets of Intralobular bronchioles that supply each bronchopulmonary segment ( right = 10, left = 8). Bronchioles split into Terminal bronchioles and these split into Respiratory Bronchioles. Respiratory Bronchioles splits into multiple Alveolar ducts which end in an Alveolar sac. Dr. Ali Mohammed Respiratory system With successive branching , the number of cartilage decreases and the number of smooth muscle increases, this allows for variation in airway diameter, during exertion and also sympathetic and parasympathetic reactions.(Bronchodilation, bronchoconstriction) The epithelial cells gradually changes from ciliated pseudo stratified columnar epithelium to simple cuboidal epithelium in terminal bronchioles Dr. Ali Mohammed Respiratory system Dr. Ali Mohammed Respiratory system Lungs contain small saccular out pocketing called alveoli. , have a thin wall specialized to promote diffusion of gases between the alveolus and the blood in the pulmonary capillaries. Alveoli,(range: 274–790 million). The spongy nature of the lung is due to the packing of millions of alveoli together Dr. Ali Mohammed Respiratory system Cells in Alveolus : 1. Type I alveolar cells – simple squamous cells where gas exchange occurs 2. Type II alveolar cells (septal cells) – free surface has microvilli – secrete alveolar fluid containing surfactant (reduces surface tension) 3. Alveolar dust cells – wandering macrophages , remove debris Dr. Ali Mohammed Respiratory system Lungs : Occupies most of the space within the thoracic cavity. Has a conical shape. Toward the midline, the lungs are separated from each other by the mediastinum and this is called the mediastinal surface. The medial aspect of each lung and the site of entrance or exit are called the hilum of lung. The structures connecting lung to the mediastinum are called Root of the lung. Costal surface of the lung ,the broad, rounded surface in contact with the thoracic wall. Dr. Ali Mohammed Respiratory system Dr. Ali Mohammed Respiratory system Pleura and Pleural Cavity : The rib cage is separated from the lung by a two layered membranous coating called the pleura. Space between the serous membrane layers is a pleural cavity. 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. Dr. Ali Mohammed