Anatomy of the Respiratory System PDF

ANATOMY AND PHYSIOLOGY OF RESPIRATORY SYSTEM BY: SHARON LEE PATINDOL  OBJECTIVES After a 20-minute discussion, BSN-3E students will be able to :  xplain the structures and functions E of the upper and lower respiratory tracts. Outline the different events in the...

ANATOMY AND PHYSIOLOGY OF RESPIRATORY SYSTEM BY: SHARON LEE PATINDOL  OBJECTIVES After a 20-minute discussion, BSN-3E students will be able to :  xplain the structures and functions E of the upper and lower respiratory tracts. Outline the different events in the Respiratory System. Identify the different Respiratory Volumes and Capacities.  Anatomic and Physiologic Overview The respiratory system is composed of the upper and lower respiratory tracts. together, the two tracts are responsible for ventilation (movement of air in and out of the airways). The upper respiratory tract, known as the upper airway, warms and filters inspired air so that the lower respiratory tract (the lungs) can accomplish gas exchange or diffusion. Gas exchange involves delivering oxygen to the tissues through the bloodstream and expelling waste gases, such as carbon dioxide, during expiration. The respiratory system depends on the cardiovascular system for perfusion, or blood flow through the pulmonary system.  Anatomy of the Respiratory System Upper Respiratory Tract : Upper airway structures consist of the nose; paranasal sinuses; pharynx, tonsils, and adenoids, larynx and trachea. Nose The external portion protrudes from the face and is supported by the nasal bones and cartilage. The anterior nares (nostrils) are the external openings of the nasal cavities. The internal portion of the nose is a hollow cavity separated into the right and left nasal cavities by a narrow vertical divider, the septum. Each nasal cavity is divided into three passageways by the projection of the turbinates from the lateral walls. The turbinate bones are also called conchae (the name suggested by their shell-like appearance). Because of their curves, these bones increase the mucous membrane surface of the nasal passages and slightly obstruct the air flowing through them.  Anatomy of the Respiratory System Upper Respiratory Tract : Upper airway structures consist of the nose; paranasal sinuses; pharynx, tonsils, and adenoids, larynx and trachea. Nose Air entering the nostrils is deflected upward to the roof of the nose, and it follows a circuitous route before it reaches the nasopharynx. It comes into contact with a large surface of moist, warm, highly vascular, ciliated mucous membrane called (nasal mucosa) that traps practically all of the dust and organisms in the inhaled air. The air is moistened, warmed to body temperature, and brought into contact with sensitive nerves. Some of these nerves detect odors; others provoke sneezing to expel irritating dust. Mucus, secreted continuously by goblet cells, covers the surface of the nasal mucosa and is moved back to the nasopharynx by the action of the cilia (short, fine hairs).  Anatomy of the Respiratory System Upper Respiratory Tract : Upper airway structures consist of the nose; paranasal sinuses; pharynx, tonsils, and adenoids, larynx and trachea. Paranasal Sinuses The paranasal sinuses consist of four pairs of bony cavities lined with nasal mucosa and ciliated pseudostratified columnar epithelium. These airspaces are connected by ducts that drain into the nasal cavity. The sinuses are named based on their location: frontal, ethmoid, sphenoid, and maxillary. Their primary function is to act as a resonating chamber for speech, and they are a common site of infection.  Anatomy of the Respiratory System Upper Respiratory Tract : Upper airway structures consist of the nose; paranasal sinuses; pharynx, tonsils, and adenoids, larynx and trachea. Pharynx, Tonsils, and Adenoids The pharynx, or throat, is a tubelike structure that connects the nasal and oral cavities to the larynx. It is divided into three regions: nasal, oral, and laryngeal. The nasopharynx is located posterior to the nose and above the soft palate. The oropharynx houses the faucial, or palatine, tonsils. The laryngopharynx extends from the hyoid bone to the cricoid cartilage. The epiglottis forms the entrance to the larynx. The adenoids, or pharyngeal tonsils, are located in the roof of the nasopharynx. The tonsils, the adenoids, and other lymphoid tissue encircle the throat. These structures are important links in the chain of lymph nodes guarding the body from invasion by organisms entering the nose and the throat. The pharynx functions as a passageway for the respiratory and digestive tracts.  Anatomy of the Respiratory System Upper Respiratory Tract : Upper airway structures consist of the nose; paranasal sinuses; pharynx, tonsils, and adenoids; larynx; and trachea. Larynx The larynx, or voice box, is a cartilaginous epithelium-lined organ that connects the pharynx and the trachea and consists of the following: Epiglottis: a valve flap of cartilage that covers the opening to the larynx during swallowing Glottis: the opening between the vocal cords in the larynx Thyroid cartilage: the largest of the cartilage structures; part of it forms the Adam’s apple Cricoid cartilage: the only complete cartilaginous ring in the larynx (located below the thyroid cartilage) Arytenoid cartilages: used in vocal cord movement with the thyroid cartilage Vocal cords: ligaments controlled by muscular movements that produce sounds; located in the lumen of the larynx  Anatomy of the Respiratory System Upper Respiratory Tract : Upper airway structures consist of the nose; paranasal sinuses; pharynx, tonsils, and adenoids; larynx; and trachea. Trachea Trachea, or windpipe, is composed of smooth muscle with C-shaped rings of cartilage at regular intervals. The cartilaginous rings are incomplete on the posterior surface and give firmness to the wall of the trachea, preventing it from collapsing. The trachea serves as the passage between the larynx and the right and left main stem bronchi, which enter the lungs through an opening called the hilus.  Anatomy of the Respiratory System Lower Respiratory Tract The lower respiratory tract consists of the lungs, which contain the bronchial and alveolar structures needed for gas exchange. Lungs The lungs are paired elastic structures enclosed in the thoracic cage, which is an airtight chamber with distensible walls. Each lung is divided into lobes. The right lung has upper, middle, and lower lobes, whereas the left lung consists of upper and lower lobes. Each lobe is further subdivided into two to five segments separated by fissures, which are extensions of the pleura.  Anatomy of the Respiratory System Lower Respiratory Tract The lower respiratory tract consists of the lungs, which contain the bronchial and alveolar structures needed for gas exchange. Pleura The lungs and wall of the thoracic cavity are lined with a serous membrane called the pleura. The visceral pleura covers the lungs; the parietal pleura lines the thoracic cavity, lateral wall of the mediastinum, diaphragm, and inner aspects of the ribs. The visceral and parietal pleura and the small amount of pleural fluid between these two membranes serve to lubricate the thorax and the lungs and permit smooth motion of the lungs within the thoracic cavity during inspiration and expiration.  Anatomy of the Respiratory System Lower Respiratory Tract The lower respiratory tract consists of the lungs, which contain the bronchial and alveolar structures needed for gas exchange. Mediastinum The mediastinum is in the middle of the thorax, between the pleural sacs that contain the two lungs. It extends from the sternum to the vertebral column and contains all of the thoracic tissue outside the lungs (heart, thymus, the aorta and vena cava, and esophagus).  Anatomy of the Respiratory System Lower Respiratory Tract The lower respiratory tract consists of the lungs, which contain the bronchial and alveolar structures needed for gas exchange. Bronchi and Bronchioles The trachea divides into the right and left main bronchi, each leading to a lung. The right bronchus is wider, shorter, and straighter, making it more likely to trap inhaled objects. By the time air reaches the bronchi, it is warm, clean, and humidified. The smaller bronchial branches lead directly to the lung's air sacs. Bronchioles produce mucus, propelled by cilia, and branch into terminal bronchioles, leading to respiratory bronchioles, which transition to gas-exchange airways. Finally, oxygen and carbon dioxide exchange occurs in the alveoli.  Anatomy of the Respiratory System Lower Respiratory Tract The lower respiratory tract consists of the lungs, which contain the bronchial and alveolar structures needed for gas exchange. Alveoli The lungs contain about 300 million alveoli, providing a surface area of 50 to 100 m². There are three types of alveolar cells. Type I cells make up 95% of the surface area and act as a barrier between air and the alveolar surface, while type II cells, which cover 5%, produce both type I cells and surfactant. Surfactant reduces surface tension, aiding lung function. The third type, alveolar macrophages, are phagocytic cells that ingest foreign matter, serving as a key defense mechanism.  Function of the Respiratory System The body's cells obtain energy through the oxidation of carbohydrates, fats, and proteins, a process that requires oxygen. Vital organs like the brain and heart depend on a continuous oxygen supply. Oxidation produces carbon dioxide, which must be removed to prevent harmful acid buildup. The respiratory system handles this by facilitating oxygen transport, respiration, ventilation, and gas exchange. OXYGEN RESPIRATION VENTILATION TRANSPORTS After tissue capillary exchanges, Ventilation involves the movement of Oxygen is delivered to cells and blood enters the pulmonary the thoracic walls and diaphragm to circulation, where oxygen change chest capacity. During carbon dioxide is removed via diffuses from the alveoli into the inspiration, the chest expands, circulating blood through blood, and carbon dioxide allowing air to flow into the lungs, capillaries. Oxygen diffuses while expiration occurs as the chest diffuses from the blood into the from capillaries into tissue cells and diaphragm return to their original alveoli due to concentration for cellular respiration, while gradients. Air movement positions, forcing air out. Inspiration carbon dioxide diffuses from replenishes oxygen and removes requires energy, while expiration is cells back into the blood for typically passive. Factors influencing carbon dioxide. This entire gas airflow, such as air pressure, removal. exchange process between air, resistance, and lung compliance, are blood, and body cells is called known as the mechanics of respiration. ventilation.  4 Different Events in Respiratory System 1. PULMONARY VENTILATION Air must move into and out of the lungs so that the gases in the alveoli of the lungs are continuously refreshed. This process of pulmonary ventilation is commonly called Breathing. 2. EXTERNAL RESPIRATION Gas exchange (oxygen loading and carbon dioxide unloading) between the pulmonary blood and alveoli must take place. Remember that in external respiration, gas exchanges are being made between the blood and the body exterior. 3. RESPIRATORY GAS TRANSPORT Oxygen and Carbon Dioxide must be transported to and from the lungs and tissue cells of the body via the bloodstream. 4. INTERNAL RESPIRATION At systemic capillaries, gas exchange occurs between the blood and cells inside the body.  PULMONARY DIFFUSION AND PULMONARY PERFUSION Pulmonary diffusion is the exchange of oxygen and carbon dioxide between the air and blood across the thin, large-surfaced alveolar-capillary membrane. Pulmonary perfusion refers to blood flow through the lungs, pumped by the right ventricle via the pulmonary artery. Some blood (about 2%) bypasses alveolar capillaries and returns to the heart without gas exchange. Bronchial arteries also supply blood to the lungs but do not engage in gas exchange, diluting the oxygenated blood leaving the lungs.  2 MECHANISMS OF BREATHING 1. INSPIRATION (INHALATION) Active phase of breathing where air is drawn into the lungs. Diaphragm contracts (moves down), rib cage lifts, increasing lung volume and lowering pressure, causing air to flow in. 2. EXPIRATION ( EXHALATION) Passive phase of breathing where air is expelled from the lungs. Diaphragm relaxes (moves up), rib cage drops, decreasing lung volume and increasing pressure, pushing air out. In forced expiration, abdominal muscles help expel air more forcefully.  RESPIRATORY VOLUMES AND CAPACITIES 1. TIDAL VOLUME The amount of air inhaled or exhaled during a normal, relaxed breath, approximately 500 ml. . INSPIRATORY RESERVE VOLUME (IRV) 2 The additional amount of air that can be inhaled with maximum effort after a normal inspiration, approximately , 3,100 ml. . EXPIRATORY RESERVE VOLUME (ERV) 3 The additional amount of air that can be forcibly exhaled after the expiration of a normal tidal volume, approximately 1,200 ml.  RESPIRATORY VOLUMES AND CAPACITIES 4. RESIDUAL VOLUME The volume of air remaining in the lungs after a maximal exhalation, which prevents lung collapse, approximately 1,200 ml. . VITAL CAPACITY 5 The total amount of air that can be exhaled after a maximal inhalation. It is the sum of the Tidal Volume, Inspiratory Reserve Volume, and Expiratory Reserve Volume. -4, 800 ml (males) - 3, 100 ml (females) 6. DEAD SPACE VOLUME The volume of air that remains in the conducting airways (trachea, bronchial, bronchioles) and does not participate in gas exchange, approximately 150 ml. THANK YOUU!!