The Respiratory System PDF

CHAPTER 23 The Respiratory System The Respiratory System Two systems that cooperate to supply O2 and eliminate CO2 are the cardiovascular and the respiratory system. 1. The respiratory system provides for GAS EXCHANGE. 2. The cardiovascular system TRANSPORTS the respiratory gases. Failure of...

CHAPTER 23 The Respiratory System The Respiratory System Two systems that cooperate to supply O2 and eliminate CO2 are the cardiovascular and the respiratory system. 1. The respiratory system provides for GAS EXCHANGE. 2. The cardiovascular system TRANSPORTS the respiratory gases. Failure of either system has the same e=ect on the body: Disrup=on of homeostasis and rapid death of cells from oxygen starva=on and buildup of waste products.  Steps involved in Respiration Respira=on supplies the body with O2 and removes CO2. 3 basic steps: 1. Pulmonary ven=la=on (breathing) inhalaAon and exhalaAon of air involves exchange of air between atmosphere and alveoli 2. External (pulmonary) respira=on exchange of gases between alveoli and blood in the pulmonary capillaries. 3. Internal (=ssue) respira=on exchange of gases between blood in the systemic capillaries and Assue cells. *Cellular respiration – use of oxygen by cells to make ATP  Structures of the Respiratory System Structurally, - divided into 2 parts: Upper respiratory system - nose, pharynx, and associated structures Lower respiratory system - larynx, trachea, bronchi, and lungs Func=onally, - divided into 2 zones: Conduc=ng zone InterconnecAng caviAes and tubes outside and within the lungs. FuncAon to moisten air and conduct it into the lungs. Respiratory zone – Consists of tubes and Assues within the lungs where gas exchange occurs. Internal Anatomy of the Nose The bony framework of the nose is formed by the frontal, nasal, and maxillary bones. The interior structures of the nose are specialized for warming moistening Hltering incoming air receiving olfactory sAmuli serving as large, hollow resonaAng chambers to modify speech sounds. Pharynx The pharynx (throat) is a muscular tube lined by a mucous membrane. The pharynx funcAons as: A passageway for air (respiraAon) and food digesAon. ResonaAng chamber for speech sounds. Houses the tonsils - parAcipate in immunological reacAons against foreign invaders. Larynx The larynx (voice box) is a passageway that connects the pharynx and trachea. It contains: thyroid carAlage epigloNs - prevents food from entering the larynx. vocal folds - produce sound when they vibrate.  Trachea Trachea (windpipe) - anterior to the esophagus, extends from the larynx to the primary bronchi. Composed of smooth muscle and C- shaped rings of carAlage. carAlage rings keep the airway open Lined with pseudostra=Ted ciliated columnar epithelium. The cilia sweep debris away from the lungs and back to the throat to be swallowed. Bronchi The trachea divides into the right and leU pulmonary bronchi. Bronchial tree - trachea, primary bronchi, secondary bronchi, terAary bronchi, bronchioles, and terminal bronchioles. Primary bronchi further divide to form smaller and smaller diameter branches. * The terminal bronchioles are the end of the conduc=ng zone Bronchi Lungs Paired organs in the thoracic cavity. Enclosed and protected by the pleural membrane. The parietal pleura - outer layer, aSached to the wall of the thoracic cavity. The visceral pleura - inner layer, covering the lungs. The pleural cavity contains a serous lubrica=ng Wuid secreted by the membranes. Extend from the diaphragm to just slightly superior to the clavicles and lie against the ribs anteriorly and posteriorly.  Lobes and Fissures of the Lungs Right lung - three lobes separated by two Hssures. LeU lung - two lobes separated by one Hssure and a depression- cardiac notch. BASE – inferior porAon, Hts over the diaphragm APEX – superior porAon Secondary bronchi give rise to branches called terAary (segmental) bronchi, which supply lung Assue called bronchopulmonary segments. Each bronchopulmonary segment consists of many lobules, which contain lymphaAcs, arterioles, venules, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.  Alveoli Conduc=ng zone ends at the terminal bronchioles - the respiratory zone begins. The respiratory zone terminates at the alveoli, the “air sacs” found within the lungs. Alveolus 2 types of alveolar cells: Type I alveolar (squamous pulmonary epithelial) cells Type II alveolar (septal) cells, and alveolar macrophages (dust cells). secrete alveolar [uid, keeps the alveolar cells moist, contains surfactant. Surfactant lowers surface tension of alveolar [uid, prevenAng the collapse of alveoli with each expiraAon. Gas exchange occurs across the alveolar- capillary membrane.  Respiratory Membrane The respiratory membrane is composed of: A layer of type I and II alveolar cells and alveolar macrophages that consAtutes the alveolar wall. An epithelial basement membrane underlying the alveolar wall A capillary basement membrane oUen fused to the epithelial basement membrane. The capillary endothelium  Steps 1. Pulmonary ven=la=on (breathing) involved in 2. External (pulmonary) respira=on Respiration 3. Internal (=ssue) respira=on Pulmonar In pulmonary ven=la=on, air [ows y between the atmosphere and the Ventilatio alveoli of the lungs because of n alterna=ng pressure diYerences created by contrac=on and relaxa=on of respiratory muscles. VenAlaAon occurs in 2 basic steps: Inhala=on Exhala=on (inspira=on) (expira=on) Pulmonary Ventilation Inhala=on (inspira=on) is the process of bringing air into the lungs. Movement of air depends on pressure changes. Expanding the lungs involves contrac=on of the main inspiratory muscle - the diaphragm. InhalaAon occurs when alveolar (intrapulmonic) pressure falls below atmospheric pressure. ContracAon of the diaphragm and external intercostal muscles INCREASES the size of the thorax Thus, DECREASING the intrapleural pressure so that the lungs expand. Expansion of the lungs decreases alveolar pressure so that air moves along the pressure gradient from the atmosphere into the lungs. Pulmonary Ventilation Exhala=on (expira=on) is the movement of air out of the lungs. ExhalaAon occurs when alveolar pressure is higher than atmospheric pressure. Relaxa=on of the diaphragm and external intercostal muscles results in elas=c recoil of the chest wall and lungs. Which INCREASES intrapleural pressure DECREASES lung volume INCREASES alveolar pressure so that air moves from the lungs to the atmosphere *Forced expiraAon employs contracAon of the internal intercostals and abdominal muscles. Position of the Diaphragm During Inhalation and Exhalation Muscles of Inhalation and Exhalation  Eupnea - normal variaAon in breathing rate and depth. Breathing Apnea - breath holding. Patterns and Dyspnea - painful or diccult breathing. Respirato ry Tachypnea - rapid breathing rate. Movemen Costal breathing - combinaAons of various paSerns of ts intercostal and extracostal muscles, usually during need for increased venAlaAon, as with exercise. Diaphragma=c breathing is the usual mode of operaAon to move air by contracAng and relaxing the diaphragm to change the lung volume. Exchange of O2 and CO2 External and Internal Respiration During external respira=on, oxygen will di=use from the alveoli into the pulmonary capillaries. *PULMONARY gas exchange. ConverAng deoxygenated blood from the right heart to oxygenated blood that returns to the leU heart. CO2 moves in the opposite direc4on During internal respira=on, oxygen will di=use from the systemic capillaries into the Assues. *SYSTEMIC gas exchange. O2 leaves blood stream, oxygenated blood is converted to deoxygenated blood. CO2 moves in the opposite direc4on  Red blood cell Capillary Capillary O2 CO2 Alveolus Respiratory Alveolar epithelium membrane Fused basement membranes Capillary endothelium Alveoli (gas- Red blood Squamous filled air cell in epithelial cell spaces) capillary of alveolar wall Transport of O2 and CO2 in the Blood Oxygen In each 100 ml of oxygenated blood: 1.5% of the O2 is dissolved in the plasma 98.5% is carried with hemoglobin (Hb) inside RBCs as oxyhemoglobin. Carbon dioxide 7% of the CO2 is dissolved in the plasma 23% of the CO2 is carried by Hb inside RBC’s 70% of the CO2 is transported as bicarbonate ions (HCO3) Respiratory Volumes and Capacities Tidal volume (TV) normal breathing volume moves about 500 ml of air *Avg adult at rest – 12 rpm Respiratory Volumes and Capacities Inspiratory reserve volume (IRV) amount of air that can be taken in forcibly over Adal volume usually between 1900mL and 3100 mL Respiratory Volumes and Capacities Expiratory reserve volume (ERV) amount of air that can be forcibly exhaled over Adal volume approximately 1200 ml Respiratory Volumes and Capacities Residual volume air remaining in lung aUer expiraAon about 1200 ml  Respiratory Volumes and Capacities Vital capacity (VC) the total amount of exchangeable air vital capacity = TV + IRV + ERV Dead space volume - air that remains in conducAng zone and never reaches alveoli Control of Respiration Respiratory center is located in the brain stem. Medullary Respiratory Center Located in the medulla GeneraAon of the rhythm of breathing Pon=ne Respiratory Group Located in the pons ModiHes rhythm of breathing during exercise, sleeping, or speaking Control of Respiration Cor=cal inWuences Voluntary control our paSern of breathing ProtecAon against water or irritaAng gases from entering the lungs Limited by build up of CO2 Chemoreceptor Central and peripheral chemoreceptors monitor levels of O2 and CO2 and provide input to the respiratory center. Hyperven=la=ng allows inhalaAon of more O2 and exhalaAon of CO2 Exercise and The respiratory and cardiovascular systems adjust in the response to both the intensity and duraAon of exercise. Respiratory As cardiac output rises, the blood [ow to the lungs, System termed pulmonary perfusion, increases as well. Aging Aging results in decreased: Vital capacity and the Blood O2 level Alveolar macrophage acAvity Respirat Ciliary acAon of respiratory epithelia ory System Consequently, elderly people are more suscepAble to pneumonia, bronchiAs, emphysema, and other issues  Hypoxia - Oxygen deHciency at the Assue level Asthma Chronic ObstrucAve Pulmonary Disease Disorders : Lung cancer Homeost Pneumonia atic Tuberculosis Imbalanc es Common cold Pulmonary edema Severe Acute Respiratory Distress