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Essentials of Anatomy and Physiology
Fifth edition
Seeley, Stephens and Tate
Chapter 15: Respiratory System
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 2.1
Organs of the Respiratory system
 Nose
 Pharynx
 Larynx
 Trachea
 Bronchi
 Lungs –
alveoli
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 13.1
Slide 13.1
Functions of the Respiratory System
 Gas exchanges between blood and air
 Exchange place in the lungs
in tiny air sacs, the alveoli
 Passageways purify, warm, and
humidify air
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.2
The Nose
 The only externally visible part of the
respiratory system
 Air enters the nose through the external
nares (nostrils)
 The interior is the nasal cavity
divided by a nasal septum
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Slide 13.3a
Upper Respiratory Tract
Figure 13.2
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Slide 13.3b
Anatomy of the Nasal Cavity
 Olfactory receptors are located in the
olfactory epithelium
 The rest of the cavity is lined with
mucous membrane
 Moistens air
 Traps incoming foreign particles
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.4a
Upper Respiratory Tract
Olfactory epithelium
Figure 13.2
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Slide 13.3b
Anatomy of the Nasal Cavity
 Lateral walls have projections called
conchae
“turbinate” bones
 Increases surface area
 Increases air turbulence within the nasal
cavity
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.4b
Anatomy of the Nasal Cavity
 The nasal cavity is separated from the
oral cavity by the palate
 Anterior hard palate (bone)
 Posterior soft palate (muscle)
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Slide 13.4b
Upper Respiratory Tract
Figure 13.2
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Slide 13.3b
Paranasal Sinuses
 Cavities within bones surrounding the
nasal cavity
 Frontal bone: 2
 Sphenoid bone: 1
 Ethmoid bone: 3
 Maxillary bones: 1 each
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.5a
Paranasal Sinuses
 Function of the sinuses
 Lighten the skull
 Act as resonance chambers for speech
 Produce mucus that drains into the nasal
cavity
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Slide 13.5b
The Paranasal Sinuses
Anterior View
Lateral View
Figure 7.11a, b
Pharynx (Throat)
 Muscular passage from nasal cavity to
larynx
 Three regions
 Nasopharynx – superior, behind nasal
cavity
 Oropharynx – middle, behind mouth
 Laryngopharynx – inferior, attached to
larynx
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.6
Pharynx (Throat)
 Nasopharynx is only
respiratory
 The oropharynx and
laryngopharynx
 Common
passageways for air
and food
 Part of two body
systems
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.6
Structures of the Pharynx
 Auditory tubes enter the nasopharynx
 Tonsils
 Pharyngeal tonsil (adenoids) in
nasopharynx
 Palatine tonsils in oropharynx
 Lingual tonsils in oropharynx
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Slide 13.7
Upper Respiratory Tract
Figure 13.2
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Slide 13.3b
Larynx (Voice Box)
 Routes air and food into proper
channels
 Plays a role in speech
 Consists of 9 cartilage structures
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.8
Anatomy of the Larynx
Anterior View
Lateral View
Figure 21.5a, b
Structures of the Larynx
 Thyroid cartilage
 Largest hyaline cartilage
 Protrudes anteriorly (Adam’s apple)
 Epiglottis
 Superior opening of the larynx
 Protects larynx during swallowing
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.9a
Structures of the Larynx
 False vocal cords
Act as valves
 True vocal cords (vocal folds)
 Vibrate with expelled air to create sound
(speech)
 Glottis – opening between vocal cords
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Slide 13.9b
Movements of the Vocal Folds
Figure 21.6
Trachea (Windpipe)
 Connects larynx with bronchi
 Lined with ciliated mucous membrane
 Walls are reinforced
 C-shaped hyaline cartilage
 Keeps tube open
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.10
The Trachea
Figure 21.7a
Primary Bronchi
 Formed by division of the trachea
 Enter the lung at the hilus
 Right bronchus: wider, shorter,
and straighter than left
 Bronchi subdivide into smaller tubes
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.11
Bronchial (Respiratory) Tree
Figure 21.8a
Lungs
 Occupy most of the thoracic cavity
 Apex is near the clavicle (superior)
 Base rests on the diaphragm (inferior)
 Each lung is divided into lobes by fissures
 Left lung – two lobes
 Right lung – three lobes
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.12a
Structure of the Lungs
Figure 21.8a
Coverings of the Lungs
 Visceral pleura covers the lung surface
 Parietal pleura lines the walls of the
thoracic cavity
 Pleural cavity contains serous fluid
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Slide 13.13
Pleural Membranes and Cavity
Figure 13.4b
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Slide 13.12b
Respiratory Tree Divisions
 Primary bronchi
 Secondary (lobar) bronchi
 Tertiary bronchi
 Bronchioles
 Terminal bronchioles
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.14
Bronchial (Respiratory) Tree
Figure 21.8a
Bronchioles
 Smallest
branches of
the bronchi
Figure 13.5a
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Slide 13.15a
Bronchioles
 All but the smallest
branches have
reinforcing cartilage
Figure 13.5a
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Slide 13.15b
Bronchioles
 Terminal
bronchioles end
in alveoli
Figure 13.5a
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Slide 13.15c
Respiratory Zone
 Structures
 Respiratory bronchioles
 Alveolar duct
 Alveoli
 Site of gas exchange
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.16
Alveoli
 Structure of alveoli
 Alveolar duct
 Alveolar sac
 Alveolus
 Gas exchange:
 takes place in the alveoli
 across the respiratory membrane
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.17
Respiratory Membrane
(Air-Blood Barrier)
 Simple squamous E.T. layer: lines
alveolar walls
 Pulmonary capillaries: cover external
surfaces of alveoli
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Slide 13.18a
Respiratory Membrane
(Air-Blood Barrier)
Figure 13.6
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Slide 13.18b
Gas Exchange
 Gas crosses the respiratory membrane
by diffusion
 Oxygen enters blood
 Carbon dioxide enters alveoli
 Macrophages add protection
 Surfactant coats exposed alveolar
surfaces
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.19
Events of Respiration
 Pulmonary ventilation – moving air in and
out of the lungs
 External respiration – gas exchange
between pulmonary blood and alveoli
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.20a
Events of Respiration
 Transport of oxygen and carbon dioxide
via the bloodstream
 Internal respiration – gas exchange
between blood in systemic capillaries
and tissue cells in body
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.20b
Mechanics of Breathing
(Pulmonary Ventilation)
 Completely mechanical process
 Depends on volume changes in the
thoracic cavity
 Volume changes lead to pressure
changes, which lead to the flow of
gases to equalize pressure
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.21a
Mechanics of Breathing
(Pulmonary Ventilation)
 Two phases
 Inspiration – flow of air into lung
 Expiration – air leaving lung
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.21b
Inspiration
 Diaphragm and intercostal muscles
contract
 The size of the thoracic cavity increases
 External air is pulled into the lungs due to
an increase in intrapulmonary volume
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Slide 13.22a
Inspiration
Figure 13.7a
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Slide 13.22b
Expiration
 A passive process
 depends on natural lung elasticity
 As muscles relax, air is pushed out of the
lungs
 Forced expiration can occur by
contracting internal intercostal muscles
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Slide 13.23a
Expiration
Figure 13.7b
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Slide 13.23b
Nonrespiratory Air Movements
 Can be caused by reflexes or voluntary
actions
 Examples
 Cough and sneeze – clear lungs of debris
 Laughing
 Crying
 Yawn
 Hiccup
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.25
Respiratory Volumes and Capacities
 Tidal volume [TV]:
 Normal breathing
 moves about 500 ml of air/breath
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Slide 13.26
Respiratory Volumes and Capacities
 Inspiratory reserve volume (IRV)
 Amount of air that can be taken in forcibly
over the tidal volume
 Usually between 2100 and 3200 ml
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.27a
Respiratory Volumes and Capacities
 Expiratory reserve volume (ERV)
 Amount of air that can be forcibly exhaled
 Approximately 1200 ml
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.27a
Respiratory Volumes and Capacities
 Residual volume
 Air remaining in lung after expiration
 About 1200 ml
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Slide 13.27b
Respiratory Volumes and Capacities
 Vital capacity
 The total amount of exchangeable air
 Vital capacity = TV + IRV + ERV
 Dead air space or volume
 Air that remains in conducting zone
Bronchi, bronchioles, ducts
 never reaches alveoli
 About 150 ml
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.28
Respiratory Volumes and Capacities
 Functional volume
 Air that actually reaches the respiratory
zone
 Usually about 350 ml
 Respiratory capacities are measured
with a spirometer
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.29
Respiratory Volumes and Capacities
 Factors that affect respiratory capacity
 Size
 Sex
 Age
 Physical condition
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 13.29
Respiratory Capacities
Figure 13.9
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Slide 13.30