The Respiratory System • Basic functions of the respiratory system • Breathing (Pulmonary Ventilation) – movement of air in and out of the lungs • Inhalation (inspiration) draws gases into the lungs. • Exhalation (expiration) forces gases out of the lungs. • Gas Conditioning – as gases pass through the nasal cavity and paransal sinuses, inhaled air becomes turbulent. The gases in the air are • warmed to body temperature • humidified • cleaned of particulate matter • Gas Exchange - respiration • Supplies body with oxygen • Disposes of carbon dioxide • Produces Sounds • Protects respiratory surfaces • Site for olfactory sensation
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The Respiratory System Basic functions of the respiratory system Breathing (Pulmonary Ventilation) – movement of air in and out of the lungs Inhalation.
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The Respiratory System• Basic functions of the respiratory system
• Breathing (Pulmonary Ventilation) – movement of air in and out of the lungs• Inhalation (inspiration) draws gases into the lungs.• Exhalation (expiration) forces gases out of the lungs.
• Gas Conditioning – as gases pass through the nasal cavity and paransal sinuses, inhaled air becomes turbulent. The gases in the air are
• warmed to body temperature• humidified• cleaned of particulate matter
• Gas Exchange - respiration• Supplies body with oxygen• Disposes of carbon dioxide
• Produces Sounds
• Protects respiratory surfaces
• Site for olfactory sensation
Respiration
• Respiration – four distinct processes must happen• Pulmonary ventilation – moving air into and out of
the lungs
• External respiration – gas exchange between the lungs and the blood
• Transport – transport of oxygen and carbon dioxide between the lungs and tissues
• Internal respiration – gas exchange between systemic blood vessels and tissues
Functional Anatomy of the Respiratory System
• Respiratory organs• Nose, nasal cavity, and paranasal sinuses
• Pharynx, larynx, and trachea
• Bronchi and smaller branches
• Lungs and alveoli
Organs of the Respiratory System
Figure 21.1
Respiratory System
• Consists of• Respiratory muscles – diaphragm and
other muscles that promote ventilation• Respiratory zone – site of external
respiration – respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
• Conducting zones• Provides rigid conduits for air to
reach the sites of gas exchange• Includes nose, nasal cavity,
pharynx, trachea• Air passages undergo 23 orders of
branching in the lungs
The Nose• Provides an airway for
respiration
• Moistens and warms air
• Filters inhaled air
• Resonating chamber for speech
• Houses olfactory receptors
• Skin is thin – contains many sebaceous glands
The Nasal Cavity
• External nares – nostrils• Divided by – nasal septum• Vestibule - anterior opening • Continuous with nasopharynx• Two types of mucous membrane
• Olfactory mucosa - Near roof of nasal cavity, houses olfactory (smell) receptors
• Respiratory mucosa - Lines nasal cavity
• Epithelium is pseudostratified ciliated columnar
• Goblet cells within epithelium • Underlying layer of lamina propria
has glands that contribute to the mucus layer and blood vessels that warm the air.
• Cilia move contaminated mucus posteriorly
Nasal Cavity
Nasal Conchae
• 3 paired bony projections along the lateral walls of the nasal cavity
• Superior and middle nasal conchae - part of the ethmoid bone
• Inferior nasal conchae - separate bone
• Function - Particulate matter deflected to mucus-coated surfaces
The Paranasal Sinuses
Figure 7.11a, b
The Pharynx• Funnel-shaped passageway• Connects nasal cavity and
mouth• Shared by the digestive and
respiratory systems• Divided into three sections by
location• Nasopharynx – superior
portion, • Oropharynx – continuous
with the oral cavity• Laryngopharynx – between
the hyoid bone and the esophagus
• Type of mucosal lining changes along its length
The Nasopharynx
• Superior to the point where food enters
• Only an air passageway
• Closed off during swallowing
• Epithelium consists of ciliated pseudostratified epithelium that moves mucus
The Oropharynx
• Arch-like entranceway – fauces• Extends from soft palate to
the epiglottis• Epithelium - stratified
squamous epithelium• Two types of tonsils in the
oropharynx• Palatine tonsils – in the
lateral walls of the fauces • Lingual tonsils – covers
the posterior surface of the tongue
The Laryngopharynx
• Passageway for both food and air
• Epithelium - stratified squamous epithelium
• Continuous with the esophagus and larynx
The Larynx• Prevent food and drink from entering the trachea
• Epithelium changes• First, pseudostratified ciliated columnar – trachea• Replaced by simple columnar - bronchi• Then simple cuboidal epithelium - bronchioles and
terminal bronchioles • Smooth muscle becomes important at the bronchioles -
controlled by the ANS (bronchoconstriction and bronchodilation).
Lobes and Surfaces of the lungs• Right lung has three lobes
• Left lung has two lobes
• Concavity on medial surface = cardiac notch
• Bronchi enter the lungs at the hilus
The Pleurae• A double-layered sac surrounding each lung
• Parietal pleura• Visceral pleura
• Pleural cavity - potential space between the visceral and parietal pleurae• Pleurae help divide the thoracic cavity
• Central mediastinum • Two lateral pleural compartments
Structures of the Respiratory Zone
• Consists of air-exchanging structures
• Respiratory bronchioles – branch from terminal bronchioles• Lead to alveolar ducts
• Lead to alveolar sacs
Structures of the Respiratory Zone
Figure 21.9b
Features Of Alveoli
Figure 21.10b
• Alveoli cell types• Type I cells site of gas exchangeand• Type II cells - secrete surfactant• Macrophages
• Surrounded by basal laminae and elastic fibers• Interconnect by way of alveolar pores• Internal surfaces - site for free movement of alveolar macrophages