Respiratory System Anatomy PDF

Anatomy of Respiratory System https://www.youtube.com/watch?v=kacMYexDgHg 25-1 Organization and Functions of the Respiratory System Consists of an upper respiratory tract and a lower respiratory tract. Conducting portion transports air....

Anatomy of Respiratory System https://www.youtube.com/watch?v=kacMYexDgHg 25-1 Organization and Functions of the Respiratory System Consists of an upper respiratory tract and a lower respiratory tract. Conducting portion transports air. includes the nose, nasal cavity, pharynx, larynx, trachea, and progressively smaller airways, from the primary bronchi to the bronchioles Respiratory portion carries out gas exchange. composed of small airways called respiratory bronchioles and alveolar ducts as well as air sacs called alveoli Generation of tracheobronchial tree : 25-2 Organization and Functions of the Respiratory System Gas exchange: Oxygen enters blood and carbon dioxide leaves Regulation of blood pH: Altered by changing blood carbon dioxide levels Carbonic acid Buffer system Sound production: Movement of air past vocal folds makes sound and speech Olfaction: Smell occurs when airborne molecules drawn into nasal cavity Thermoregulation: Heating and cooling of body Protection: Against microorganisms by preventing entry and removing them 25-3 4  The upper respiratory tract includes The nose pharynx adenoids tonsils epiglottis larynx, and trachea. 5  The nose The nose has several important functions: Provides an airway for ventilation Moistens and warms entering air Filters and cleans inspired air Serves as a resonating chamber for speech Houses olfactory receptors  The nasal cavity Performs many important functions 1.Filters the air (hair and turbulence) 2.Warms and humidifies the air (capillary plexuses and mucus) 3.Traps particulates (mucus) 4.Kills bacteria (lysozyme and defensins) 5.Removes contaminated mucus (escalator) 6.Sneezing dislodges irritants  The Pharynx Passageway for air (nasal cavity to larynx) and food (oral cavity to oesophagus) Contains lymphoid tissue (tonsils) which help to protect against pathogens M&H: Figure 22.3b Pharynx Partitioned into three adjoining regions: nasopharynx oropharynx laryngopharynx 25-9 25-10 The larynx… continue A cartilaginous structure that surrounds and protects the glottis (opening of the M&H: Figure 22.3c trachea) Three functions provides an open (patent) airway routes air and food into proper channels Epiglottis facilitates voice Thyroid cartilage production Vocal fold Cricoid cartilage Functions of the Upper Respiratory Tract Cleans air Guard hairs Mucus Cilia Warms air Moistens air 25-12  Trachea A flexible, slightly rigid tubular organ often referred to as the “windpipe.” Extends through the mediastinum and lies immediately anterior to the esophagus, inferior to the larynx, and superior to the primary bronchi of the lungs. Anterior and lateral walls of the trachea are supported by 15 to 20 C-shaped tracheal cartilages. cartilage rings reinforce and provide some rigidity to the tracheal wall to ensure that the trachea remains open (patent) at all times cartilage rings are connected by elastic sheets called anular ligaments 25-13 14 Trachea 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. Conducting zone Trachea to terminal bronchioles which is ciliated for removal of debris Passageway for air movement Respiratory zone Respiratory bronchioles to alveoli Site for gas exchange 25-15 The bronchi and subdivisions Primary bronchi (diametre Ø ~1 cm) Lobar (secondary) bronchi Conducting Segmental (tertiary) bronchi zone Bronchioles (Ø < 1 mm) Terminal bronchioles (Ø < 0.5 mm) Respiratory bronchioles (Ø < 0.5 mm) Bronchial Tree A highly branched system of air-conducting passages that originate from the left and right primary bronchi. Progressively branch into narrower tubes as they diverge throughout the lungs before terminating in terminal bronchioles. Incomplete rings of hyaline cartilage support the walls of the. primary bronchi to ensure that they remain open. 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. The primary bronchi enter the hilum of each lung together with the pulmonary vessels, lymphatic vessels, and nerves. Each primary bronchus then branches into several secondary bronchi (or lobar bronchi). 25-17 Bronchial Tree The left lung has two secondary bronchi since it has two lobes. The right lung has three lobes and three secondary bronchi. They further divide into tertiary bronchi. The right lung is supplied by 10 tertiary bronchi, and the left lung is supplied by 8 to 10 tertiary bronchi. Each tertiary bronchus is called a segmental bronchus because it supplies a part of the lung called a bronchopulmonary segment. Terminal Bronchioles Last passages before aveoli Still have Cilia 25-18 25-19 25-20 25-21 Bronchial Tree Respiratory portion of the respiratory system respiratory bronchioles alveolar ducts Alveoli Non-Acinus -Conducting zone Trachea to terminal bronchioles which is ciliated for removal of debris, mucus lined Cartilage holds tube system open and smooth muscle controls tube diameter Acinus Portion - Respiratory zone Respiratory bronchioles to alveoli Site for gas exchange Area the size of a football field 25-22 Respiratory Zone 25-23 Respiratory Bronchioles, Alveolar Ducts, and Alveoli Contain small saccular outpocketings called alveoli. An alveolus is about 0.25 to 0.5 millimeter in diameter. Its thin wall is 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 lungs, which contain approximately 300–400 million alveoli. The spongy nature of the lung is due to the packing of millions of alveoli together. Phagocytosis removes small particles in alveoli 25-24 surfactant Is an oily secretion Contains phospholipids and proteins Coats alveolar surfaces and reduces surface tension of each lung. 25-25 Lower Respiratory Tract Convey air to alveoli Clean air and remove particles by mucociliary elevator Macrophages in aveoli phagocytize foreign particles – last line of defense 25-26  Alveoli and the respiratory membrane M&H: Figure 22.9a&b 28 Gross Anatomy of the Lungs Each lung has a conical shape. Its wide, concave base rests upon the muscular diaphragm. Its relatively blunt superior region, called the apex or (cupola), 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. 25-29  The right lung is divided into three lobes (upper, middle, and lower) the left lung into two lobes (upper and lower) 25-30 25-31  Thoracic Inlet Superior opening of the thorax Curvature of 1st rib with associated structures Thoracic Outlet Inferior opening of the thorax 12th rib and associated structures & Xiphisternal joint 25-32 33 34 35 36 37 38 39  Pleura and Pleural Cavities The outer surface of each lung and the adjacent internal thoracic wall are lined by a serous membrane called pleura, which is formed from simple squamous epithelium. 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 hilum of each lung. 40 Pleura and Pleural Cavities The potential space between these serous membrane layers is a pleural cavity. The pleural membranes produce a thin, serous fluid that circulates in the pleural cavity and acts as a lubricant, ensuring minimal friction during breathing. 25-41 25-42  Surface Anatomy TRACHEA 1. Starts from cricoid cartilage to sternal angle anteriorly and T4 spinous process posteriorly, where it divides into left and right main stem bronchi. 2. Trachea has intra and extra thoracic components. This has important bearing in the understanding of physiology of variable obstruction. 43  MANUBRIUM ANGLE – The angle between the body and Manubrium. Many important land marks occur at this level. It is called Louis Angle. – 2nd rib articulates to Manubrium at this site. The ribs are counted anteriorly starting from this point. – Carina of trachea is at this level. 44  LINES – Midsternal Line: A vertical line down the middle of sternum – Parasternal Line: A vertical line along lateral edge of sternum – Mid-Clavicular Line: A vertical line from middle of clavicle – Anterior Axillary Line: A vertical line along anterior axillary fold – Mid-Axillary Line: A vertical line at mid point between anterior and posterior axillary line. – Posterior Axillary Line: Along post axillary fold – Scapular Line: Inferior angle of scapula – Vertebral line: Over spinous processes in the 45 midline Surface markings of the lobes of the lung (UL, upper lobe; ML, middle lobe; LL, lower lobe 46 Surface markings of the lobes of the lung (UL, upper lobe; ML, middle lobe; LL, lower lobe 47 Surface markings of the lobes of the lung (UL, upper lobe; ML, middle lobe; LL, lower lobe 48 Surface markings of the lobes of the lung Anterior Chest 49 Surface markings of the lobes of the lung Posterior Chest 50 Surface markings of the lobes of the lung (UL, upper lobe; ML, middle lobe; LL, lower lobe 51  Right Lung: – With a marking pen start 3 centimeters above clavicle in midclavicular line, come down along right parasternal line , join to 6th rib in midclavicular line, to 8th rib in mid-axillary line, to 10th rib posteriorly, to vertebral line posteriorly. 52  Left Lung: – At angle of Louis, follow the outer margin of the heart to 6th rib in mid-clavicular line. – Appreciate that apex of lung is just under the skin easily palpable in the supraclavicular space. – Pancoast tumor and TB occur at this site. Hence, the apex of lungs should be routinely examined. 53  Surface Anatomy of Lobes – Draw oblique fissure by drawing a line from 6th rib in MCN. to 5th rib in mid axillary line and along the medial margin of scapula (with the patients hands on head) to 3rd spinous process Transverse fissure can be drawn by drawing a line from 5th rib in mid- axillary line to 4th rib anteriorly 54 - Once the fissures are drawn over the outline of lungs, one can easily recognize the surface anatomy of lobes of lungs. One can then appreciate the importance of examining the patient all around the chest to cover the lobes. - Most of lower lobe is in back, upper lobe is in front and all of middle lobe is in front. - In the axilla all of the three lobes can be seen. 55 Bony Thorax (Thoracic Cage) Figure56 7.19a  Sternum (Breastbone) A dagger-shaped, flat bone that lies in the anterior midline of the thorax Results from the fusion of three bones – the superior manubrium, the body, and the inferior xiphoid process Anatomical landmarks include the jugular (suprasternal) notch, the sternal angle, and the xiphisternal joint 57  Ribs There are twelve pair of ribs forming the flaring sides of the thoracic cage All ribs attach posteriorly to the thoracic vertebrae The superior 7 pair (true, or vertebrosternal ribs) attach directly to the sternum via costal cartilages Ribs 8-10 (false, or vertebrocondral ribs) attach indirectly to the sternum via costal cartilage Ribs 11-12 (floating, or vertebral ribs) have no anterior attachment 58  Structure of Rib Bowed, flat bone consisting of a head, neck, tubercle, and shaft 59 Figure 7.20 – Thoracic Inlet Superior opening of the thorax Curvature of 1st rib with associated structures – Thoracic Outlet Inferior opening of the thorax 12th rib and associated structures & Xiphisternal joint 60  Thoracic Wall Dimensional Changes During Respiration Lateral dimensional changes occur with rib movements. Elevation of the ribs increases the lateral dimensions of the thoracic cavity, while depression of the ribs decreases the lateral dimensions of the thoracic cavity. 25-61 25-62  Muscles that Move the Ribs The scalenes help increase thoracic cavity dimensions by elevating the first and second ribs during forced inhalation. The ribs elevate upon contraction of the external intercostals, thereby increasing the transverse dimensions of the thoracic cavity during inhalation. Contraction of the internal intercostals depresses the ribs, but this only occurs during forced exhalation. Normal exhalation requires no active muscular effort. 25-63 25-64  Muscles that Move the Ribs Two posterior thorax muscles also assist with respiration. These muscles are located deep to the trapezius and latissimus dorsi, but superficial to the erector spinae muscles. The serratus posterior superior elevates ribs 2–5 during inhalation, and the serratus posterior inferior depresses ribs 8–12 during exhalation. In addition, some accessory muscles assist with respiratory activities. 25-65 25-66  Muscles that Move the Ribs The pectoralis minor, serratus anterior, and sternocleidomastoid help with forced inhalation, while the abdominal muscles (external and internal obliques, transversus abdominis, and rectus abdominis) assist in active exhalation. 25-67  Muscles that Move the Ribs Volume of thoracic cavity increases Decreases internal gas pressure Action of the diaphragm Diaphragm flattens Action of intercostal muscles Contraction raises the ribs Deep inspiration requires Scalenes Sternocleidomastoid Pectoralis minor 25-68  The Mechanics of Breathing Inhalation: always active Exhalation: active or passive Muscle Groups of Inhalation 1. Diaphragm: contraction draws air into lungs 75% of normal air movement 25-69 2. External intrecostal muscles: assist inhalation 25% of normal air movement 3. Accessory muscles assist in elevating ribs: Sternocleidomastoid. serratus anterior. pectoralis minor. scalene muscles. 25-70  Muscles of Active Exhalation 1. Internal intercostal and transversus thoracis muscles: depress the ribs 2. Abdominal muscles: compress the abdomen force diaphragm upward 25-71