Human Anatomy, 3rd edition Prentice Hall, © 2001 The Respiratory System Chapter 24

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 Cardiovascular

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

Human Anatomy, 3rd edition Prentice Hall, © 2001 Divisions of the Respiratory System –Respiratory tract Passageways through which air will move Terminate in the alveoli Upper respiratory system –All structures superior to the larynx –Functions – intake, moistening, filtering, sensing Lower respiratory system –Larynx and all structures below it –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 lots of goblet cells (mucus secretion) Entraps & removes dust and other particles Moistens incoming air Dissolves airborne chemicals for olfactory sensation –Capillaries under epithelium in nasal cavity Warm incoming air –The common cold

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

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 Vestibule

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

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Nasal Cavity –Nasal septum (vomer & perpendicular plate of the ethmoid bone) divides into left and right sides –Hard & soft palate form the floor –Nasal conchae cause turbulence through meatuses –Internal nares lead to the nasopharynx

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Nasal Cavity

Human Anatomy, 3rd edition Prentice Hall, © 2001 Paranasal Sinuses –Frontal, sphenoid, ethmoidal, and maxillary sinuses –Functions Lighten skull bones Produce mucus Resonate during sound production

Human Anatomy, 3rd edition Prentice Hall, © 2001 Paranasal Sinuses

Human Anatomy, 3rd edition Prentice Hall, © 2001 Paranasal Sinuses

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Pharynx –Area from the internal nares to the larynx –Shared between the respiratory and digestive systems –Divided into 3 regions Nasopharynx Oropharynx Laryngopharynx

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

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Larynx –Connects the laryngopharynx to the trachea –Formed by 9 cartilages Thyroid – Adam’s apple Cricoid – forms a complete ring Epiglottis – looks like a trap door 3 pairs of smaller cartilages –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 (anterior)

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

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

Human Anatomy, 3rd edition Prentice Hall, © 2001 Voice Production –Laryngeal ligaments lie under the mucous membrane –Intrinsic muscles attached to the cartilages Control the tension of vocal folds –Sound production Air flowing over the vocal folds (through the glottis) produces sound waves –Resonating chambers (echoing, amplification

Human Anatomy, 3rd edition Prentice Hall, © 2001 Movements of the Larynx During Swallowing –Tongue forces bolus into the oropharynx –Larynx is elevated Extrinsic laryngeal muscles –Epiglottis closes over glottis –Pharyngeal muscles push bolus into esophagus –Larynx returns to normal position

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

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

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

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

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

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Bronchi, Bronchioles, & Alveoli –The trachea divides into primary right & left bronchii Enter the lungs –The primary bronchi divide into secondary bronchi Each lobe of the lungs receives its own secondary bronchus –The secondary bronchi divide into tertiary bronchi –The tertiary bronchi divide many times Give rise to the bronchioles –The bronchioles divide into terminal bronchioles which divide into respiratory bronchioles –The respiratory bronchioles divide into alveolar ducts which end in alveoli –Respiratory tree

Human Anatomy, 3rd edition Prentice Hall, © 2001 Bronchi, Bronchioles, & 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 the alveoli) –Asthma

Human Anatomy, 3rd edition Prentice Hall, © 2001 Changes as the Respiratory Tree Branches

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Alveoli –The site of gas exchange with the blood –Each is closely associated with a capillary –The wall of the alveolus + the wall of the capillary = the respiratory membrane –Gas exchange occurs by diffusion

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

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

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Alveoli –The alveolar epithelium contains 2 cell types Alveolar Type 1 cells –Allow diffusion of gases –Emphysema Alveolar Type 2 cells –Secrete surfactant –Respiratory Distress Syndrome –The alveoli also contain macrophages

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

Human Anatomy, 3rd edition Prentice Hall, © 2001 The Lungs –Soft, spongy, cone-shaped Top = apex Bottom = base –The right lung has 3 lobes, the left lung has 2 lobes Hilus –Blood supply Pulmonary arteries Pulmonary veins

Human Anatomy, 3rd edition Prentice Hall, © 2001 Lobes of the Lungs

Human Anatomy, 3rd edition Prentice Hall, © 2001 Blood Supply to the Lungs

Human Anatomy, 3rd edition Prentice Hall, © 2001 Breathing –Lungs are prevented from collapsing Intrapleural pressure is always slightly lower than the intrapulmonary pressure –Muscles involved in breathing Diaphragm –Inhaling & exhaling External intercostals –Inhaling Internal intercostals –Exhaling Abdominal muscles –Involved in deep breathing –Inhaling is active work, exhaling is passive