The Respiratory System Chapter 15

Human Anatomy, 3rd edition Prentice Hall, © 2001 Introduction Responsible for the exchange of gases between the body and the external environment. –Cells need a supply of O 2 and to eliminate CO 2 –3 basic processes Breathing External respiration Internal respiration Two systems supply O 2 & eliminate CO 2 –Respiratory system –Cardiovascular system

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Respiratory Tract Passageways through which air will move Terminate in the alveoli

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Respiratory Tract Upper respiratory system –Superior to the larynx –Functions – intake, moistening, filtering, sensing Lower respiratory system –Larynx and below –Functions – sound production, transport of air, gas exchange

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Respiratory Epithelium Lines the upper respiratory system Pseudostratified ciliated columnar epithelium with goblet cells –Entraps & removes dust –Moistens incoming air –Olfactory sensation Capillaries warm incoming air The common cold

Human Anatomy, 3rd edition Prentice Hall, © 2001 Surface View of the Epithelium

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Nose Primary entrance to the respiratory system –Bone & cartilage –External nares

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Nasal Cavity Nasal septum –Divides into left and right sides Hard & soft palate form the floor Nasal conchae cause turbulence through nasal cavity Internal nares lead to the pharynx

Human Anatomy, 3rd edition Prentice Hall, © 2001 Paranasal Sinuses Cavities in cranial bones Functions –Lighten skull bones –Produce mucus –Resonate during sound production

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Pharynx Area from the internal nares to the larynx Shared between the respiratory and digestive systems

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Larynx Connects the pharynx to the trachea Lined by mucus- producing columnar epithelium Functions –Produces sound Vocal folds –Keeps food from entering the airways Vestibular folds Epiglottis

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Larynx Formed by 9 cartilages –Thyroid cartilage Adam’s apple –Epiglottis Closes glottis

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Larynx

Voice Production Ligaments lie under mucous membrane Muscles attached to the cartilages –Control vocal ligament tension Sound production –Air flowing over vocal folds (through the glottis) produces sound waves Resonating chambers

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Trachea Extends from larynx to primary bronchi The “windpipe” Structure –Incomplete cartilaginous rings Lined by mucus- producing epithelium Function – passageway for air

Human Anatomy, 3rd edition Prentice Hall, © 2001 Bronchi, Bronchioles, & Alveoli Trachea divides into Primary bronchii divide into Secondary bronchi divide into Tertiary bronchi divide into Bronchioles divide into Terminal bronchioles divide into Respiratory bronchioles divide into Alveolar ducts end in Alveoli

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Respiratory Tree

Human Anatomy, 3rd edition Prentice Hall, © 2001 Changes as the Respiratory Tree Branches As branching of bronchi becomes more extensive –Rings of cartilage become plates –Smooth muscle increases –Columnar epithelium becomes cuboidal, then squamous (in alveoli) Asthma

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Alveoli Site of gas exchange with the blood Closely associated with capillaries Wall of the alveolus + wall of capillary –Respiratory membrane Gas exchange occurs by diffusion

Human Anatomy, 3rd edition Prentice Hall, © 2001 Alveoli

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Alveoli Alveolar epithelium contains: –Alveolar Type 1 cells Gas exchange Emphysema –Alveolar Type 2 cells Secrete surfactant Respiratory Distress Syndrome Macrophages

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Lungs Soft, spongy, cone-shaped Right lung –3 lobes Left lung –2 lobes

Human Anatomy, 3rd edition Prentice Hall, © 2001 Blood Supply to the Lungs –Pulmonary arteries, pulmonary veins

Human Anatomy, 3rd edition Prentice Hall, © 2001 Breathing Lungs are prevented from collapsing –Pressure in the pleural cavity is always slightly lower than the pressure in lungs

Human Anatomy, 3rd edition Prentice Hall, © 2001 Inhaling is Active Work Diaphragm Intercostals contract Other muscles in thorax contract Thoracic cage expands Lung volume increases Pressure in lungs drops below atmospheric pressure Air rushes in

Human Anatomy, 3rd edition Prentice Hall, © 2001 Exhaling is Passive Diaphragm relaxes Intercostal muscles relax Thoracic cage drops Lung volume decreases Pressure in lungs increases above atmospheric pressure Air rushes out