Respiratory System Anatomy Part 1 PDF

The Respiratory system - part1 Human Anatomy & Physiology Spring semester 2024  Organization and Functions of the Respiratory System Consists of an upper respiratory tract (nose to larynx) and a lower respiratory tract (trachea and below). Conducting portion: transp...

The Respiratory system - part1 Human Anatomy & Physiology Spring semester 2024  Organization and Functions of the Respiratory System Consists of an upper respiratory tract (nose to larynx) and a lower respiratory tract (trachea and below). Conducting portion: transports air. - includes the nose, nasal cavity, paranasal sinuses, pharynx, larynx, trachea, and progressively smaller airways, from the primary bronchi to the terminal bronchioles. Respiratory portion: carries out gas exchange. - composed of small airways called respiratory bronchioles and alveolar ducts and air sacs (alveoli).  Respiratory System Functions 1. supplies the body with oxygen and disposes of carbon dioxide 2. filters inspired air 3. produces sound 4. contains receptors for smell 5. Get rid of some excess water and heat 6. helps regulate blood acidity (pH)  Breathing Breathing (ventilation) consists of two cyclic phases: 1. inhalation, also called inspiration - draws gases into the lungs. 2. exhalation, also called expiration - forces gases out of the lungs.  Respiratory mucosa A layer of pseudostratified ciliated columnar epithelial cells that secrete mucus. Found in nose, sinuses, pharynx, larynx and trachea. Cilia move mucus towards the mouth. Mucus can trap contaminants.  Organs of the Respiratory system Nose Pharynx Larynx Trachea Bronchi Lungs – alveoli Upper Respiratory Tract Anatomy of the Nasal Cavity Olfactory receptors are located in the mucosa on the superior surface The rest of the cavity is lined with respiratory mucosa Moisturizes air Traps foreign particles Lateral walls have projections called conchae (Increases surface area). The nasal cavity is separated from the oral cavity by the palate: Anterior hard palate (bone) Posterior soft palate (muscle) Anatomy of the Nasal Cavity  Paranasal Sinuses Paranasal sinuses are cavities within bones, surrounding the nasal cavity: Frontal sinus Sphenoid sinus Ethmoidal sinus Maxillary sinus Function of the sinuses: Less weight of the skull Act as resonance chambers for speech Produce mucus that drains into the nasal cavity  Pharynx (Throat) Muscular passage from nasal cavity to larynx Three regions of the pharynx Nasopharynx – superior region behind nasal cavity Oropharynx – middle region behind mouth Laryngopharynx – inferior region attached to larynx  Nasopharynx In the lateral walls of the nasopharynx, auditory/eustachian tubes connect the nasopharynx to the middle ears bilaterally. Posterior nasopharynx houses the adenoids.  Oropharynx The middle pharyngeal region. Immediately posterior to the oral cavity. Common respiratory and digestive pathway through which both air and swallowed food and drinks pass. Palatine tonsils are on the lateral wall between the arches, and the lingual tonsils are at the base of the tongue. They are Lymphatic organs that provide defense against ingested or inhaled foreign materials  Laryngopharynx Also called hypopharynx. Inferior region of the pharynx. Ends at the superior border of the esophagus and the epiglottis of the larynx. Permits passage of both food and air.  Larynx (voice box) Voice box is a short, cylindrical airway ends in the trachea. Prevents swallowed materials from entering the lower respiratory tract. Conducts air into the lower respiratory tract. Produces sounds. Supported by a framework of nine pieces of cartilage.  Larynx Nine C-rings of cartilage form the framework of the larynx 1) thyroid cartilage – (1) Adam’s apple, hyaline, anterior attachment of vocal folds, testosterone increases size after puberty. 2) cricoid cartilage – (1) hyaline 3) arytenoid cartilages – (2) hyaline, posterior attachment of vocal folds, hyaline. 4) cuneiform cartilages - (2) hyaline. 5) corniculate cartlages - (2) hyaline. 6) epiglottis – (1) elastic cartilage  Larynx Muscular walls aid in voice production and the swallowing reflex. Glottis – the superior opening of the larynx Epiglottis – prevents food and drink from entering airway when swallowing  Structures of the Larynx Vocal cords (vocal folds): Vibrate with expelled air to create sound (speech). Glottis – opening between vocal cords. Inferior ligaments are called the vocal folds: - are true vocal cords: because they produce sound when air passes between them. Superior ligaments are called the vestibular folds: - are false vocal cords: because they have no function in sound production, but protect the vocal folds. The tension, length, and position of the vocal folds determine the quality of the sound. Sound production Intermittent release of exhaled air through the vocal folds Loudness depends on the force with which air is exhaled through the cords Pharynx, oral cavity, nasal cavity, paranasal sinuses act as resonating chambers that add quality to the sound Muscles of the face, tongue, and lips help with enunciation of words The Larynx Voice production Length of the vocal folds changes with pitch Loudness depends on the force of air across the vocal folds Intrinsic muscle of larynx 1. Lateral cricoarytenoid---vocal adduction 2. Posterior cricoarytenoid---vocal abduction Innervation of the larynx Recurrent laryngeal nerves (branch of vagus). Movements of the Vocal Folds  Trachea (Windpipe) Connects larynx with bronchi Lined with ciliated mucosa Beat continuously in the opposite direction of incoming air Expel mucus loaded with dust and other debris away from lungs Walls are reinforced with C-shaped hyaline cartilage At the 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 most inferior tracheal cartilage separates the primary bronchi at their origin and forms an internal ridge called the carina. PRIMARY BRONCUS Right & left primary bronchi Carina marks line of separation between 2 bronchi Has cartilaginous C shaped supporting rings Right primary bronchus is shorter, wider, and more vertically oriented than the left primary bronchus. Foreign particles are more likely to lodge in the right primary bronchus. Hilum of lung : Access for entry of pulmonary vessels, nerves, bronchi.  Bronchial Tree Secondary bronchi→ tertiary bronchi→ bronchioles→ terminal bronchioles. with successive branching amount of cartilage decreases and amount of smooth muscle increases, this allows for variation in airway diameter during exertion and when sympathetic division active → bronchodilation mediators of allergic reactions like histamine → bronchoconstriction epithelium gradually changes from ciliated pseudostratified columnar epithelium to simple cuboidal epithelium in terminal bronchioles. Bronchopulmonary Segments  Conduction vs. Respiratory zones Most of the tubing in the lungs makes up conduction zone Consists of nasal cavity to terminal bronchioles The respiratory zone is where gas is exchanged Consists of alveoli, alveolar sacs, alveolar ducts and respiratory bronchioles  Gross Anatomy of the Lungs Each lung has a conical shape. Its wide, concave base rests upon the muscular diaphragm. Its superior region called the apex projects superiorly to a point that is slightly superior and posterior to the clavicle. Both lungs are bordered by the thoracic wall anteriorly, laterally, and posteriorly, and supported by the rib cage. Toward the midline, the lungs are separated from each other by the mediastinum. The relatively broad, rounded surface in contact with the thoracic wall is called the costal surface of the lung. Gross Anatomy of the Lungs  Lungs Left lung: divided into 2 lobes by oblique fissure. smaller than the right lung. cardiac notch accommodates the heart. Right lung: divided into 3 lobes by oblique and horizontal fissure. located more superiorly in the body due to liver on right side.  Pleura and Pleural Cavities 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. 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 effusion – pleuritis with too much fluid in the pleural space.  Blood supply of Lungs Pulmonary circulation. Bronchial circulation – bronchial arteries supply oxygenated blood to lungs, bronchial veins carry away deoxygenated blood from lung tissue → superior vena cava. Response of two systems to hypoxia: 1. Pulmonary vessels undergo vasoconstriction. 2. Bronchial vessels like all other systemic vessels undergo vasodilation.  Respiratory Bronchioles, Alveolar Ducts, and Alveoli Lungs contain small saccular outpocketings called alveoli. They have a thin wall specialized to promote diffusion of gases between the alveolus and the blood in the pulmonary capillaries. Gas exchange can take place in the respiratory bronchioles and alveolar ducts as well as in the alveoli, each lung contains approximately 300 to 400 million alveoli. The spongy nature of the lung is due to the packing of millions of alveoli together.  Respiratory Membrane Respiratory membrane: is the set of layers gases must cross between the alveoli (air) and blood capillaries (blood). They are 4 layers. 1. squamous cells of alveoli. 2. basement membrane of alveoli. 3. basement membrane of capillaries 4. simple squamous cells of capillaries Cells in alveolus: 1. Type I cells : simple squamous cells forming lining. 2. Type II cells (septal cells): secrete surfactant. 3. Alveolar macrophages The End