Transcript Figure 13.5a - Cloudfront.net

13
PART A
The Respiratory
System
PowerPoint® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University
ESSENTIALS
OF HUMAN
ANATOMY
& PHYSIOLOGY
EIGHTH EDITION
ELAINE N. MARIEB
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Organs of the Respiratory system
 1. Nose
 2. Pharynx
 3. Larynx
 4. Trachea
 5. Bronchi
 6. Lungs –
alveoli
Figure 13.1
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Function of the Respiratory System
 A. Oversees gas exchanges between the blood
and external environment
 B. Exchange of gasses takes place within the
lungs in the alveoli
 C. Passageways to the lungs purify, warm,
and humidify the incoming air
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The Nose
 1. The only externally visible part of the
respiratory system
 2. Air enters the nose through the external
nares (nostrils)
 3. The interior of the nose consists of a nasal
cavity divided by a nasal septum
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Upper Respiratory Tract
Figure 13.2
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Anatomy of the Nasal Cavity
 A. Olfactory receptors are located in the
mucosa on the superior surface
 B. The rest of the cavity is lined with
respiratory mucosa
 1. Moistens air
 2. Traps incoming foreign particles
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Anatomy of the Nasal Cavity
 C. Lateral walls have projections called
conchae
 1. Increases surface area
 2. Increases air turbulence within the nasal
cavity
 D. The nasal cavity is separated from the oral
cavity by the palate
 1. Anterior hard palate (bone)
 2. Posterior soft palate (muscle)
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Paranasal Sinuses
 A. Cavities within bones surrounding the
nasal cavity
 1. Frontal bone
 2. Sphenoid bone
 3. Ethmoid bone
 4. Maxillary bone
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Paranasal Sinuses
 B. Function of the sinuses
 1. Lighten the skull
 2. Act as resonance chambers for speech
 3. Produce mucus that drains into the nasal
cavity
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Pharynx (Throat)
 A. Muscular passage from nasal cavity to larynx
 B. Three regions of the pharynx
 1. Nasopharynx – superior region behind nasal
cavity
 2. Oropharynx – middle region behind mouth
 3. Laryngopharynx – inferior region attached to
larynx
 C. The oropharynx and laryngopharynx are common
passageways for air and food
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Structures of the Pharynx
 A. Auditory tubes enter the nasopharynx
 B. Tonsils of the pharynx
 1. Pharyngeal tonsil (adenoids) in the
nasopharynx
 2. Palatine tonsils in the oropharynx
 3. Lingual tonsils at the base of the tongue
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Larynx (Voice Box)
 A. Routes air and food into proper channels
 B. Plays a role in speech
 C. Made of eight rigid hyaline cartilages and
a spoon-shaped flap of elastic cartilage
(epiglottis)
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Structures of the Larynx
 1. Thyroid cartilage
 Largest hyaline cartilage
 Protrudes anteriorly (Adam’s apple)
 2. Epiglottis
 Superior opening of the larynx
 Routes food to the larynx and air toward
the trachea
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Structures of the Larynx
 3. Vocal cords (vocal folds)
 Vibrate with expelled air to create sound
(speech)
 4. Glottis – opening between vocal cords
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Trachea (Windpipe)
 A. Connects larynx with bronchi
 B. Lined with ciliated mucosa
 Beat continuously in the opposite direction
of incoming air
 Expel mucus loaded with dust and other
debris away from lungs
 C. Walls are reinforced with C-shaped hyaline
cartilage
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Primary Bronchi
 A. Formed by division of the trachea
 B. Enters the lung at the hilus
(medial depression)
 C. Right bronchus is wider, shorter,
and straighter than left
 D. Bronchi subdivide into smaller
and smaller branches
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Lungs
 Occupy most of the thoracic cavity
 A. Apex is near the clavicle (superior
portion)
 Base rests on the diaphragm (inferior
portion)
 B. Each lung is divided into lobes by
fissures
 Left lung – two lobes
 Right lung – three lobes
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Lungs
Figure 13.4b
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Coverings of the Lungs
 1. Pulmonary (visceral) pleura covers the
lung surface
 2. Parietal pleura lines the walls of the
thoracic cavity
 Pleural fluid fills the area between layers
of pleura to allow gliding
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Respiratory Tree Divisions
 1. Primary bronchi
 2. Secondary bronchi
 3. Tertiary bronchi
 4. Bronchioli
 5. Terminal bronchioli
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Bronchioles
 A. Smallest
branches of
the bronchi
Figure 13.5a
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Bronchioles
 B. All but
the smallest
branches
have
reinforcing
cartilage
Figure 13.5a
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Bronchioles
 C. Terminal
bronchioles
end in alveoli
Figure 13.5a
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Respiratory Zone
 A. Structures
 1. Respiratory bronchioli
 2. Alveolar duct
 3. Alveoli
 B. Site of gas exchange
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Alveoli
 A. Structure of alveoli
 1. Alveolar duct
 2. Alveolar sac
 3. Alveolus
 B. Gas exchange takes place within the
alveoli in the respiratory membrane
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Respiratory Membrane (Air-Blood Barrier)
 A. Thin squamous epithelial layer lining
alveolar walls
 B. Pulmonary capillaries cover external
surfaces of alveoli
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Respiratory Membrane (Air-Blood Barrier)
Figure 13.6
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Gas Exchange
 A. Gas crosses the respiratory membrane by
diffusion
 1. Oxygen enters the blood
 2. Carbon dioxide enters the alveoli
 B. Macrophages add protection
 C. Surfactant coats gas-exposed alveolar
surfaces
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Events of Respiration
 A. Pulmonary ventilation – moving air in and
out of the lungs
 B. External respiration – gas exchange
between pulmonary blood and alveoli
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Events of Respiration
 C. Respiratory gas transport – transport of
oxygen and carbon dioxide via the
bloodstream
 D. Internal respiration – gas exchange
between blood and tissue cells in systemic
capillaries
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Mechanics of Breathing (Pulmonary
Ventilation)
 A. Completely mechanical process
 B. Depends on volume changes in the
thoracic cavity
 C. Volume changes lead to pressure changes,
which lead to the flow of gases to equalize
pressure
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Mechanics of Breathing (Pulmonary
Ventilation)
 D. Two phases
 1. Inspiration – flow of air into lung
 2. Expiration – air leaving lung
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Inspiration
 1. Diaphragm and intercostal muscles
contract
 2. The size of the thoracic cavity increases
 3. External air is pulled into the lungs due to
an increase in intrapulmonary volume
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Inspiration
Figure 13.7a
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Expiration
 A. Largely a passive process which depends
on natural lung elasticity
 B. As muscles relax, air is pushed out of the
lungs
 C. Forced expiration can occur mostly by
contracting internal intercostal muscles to
depress the rib cage
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Expiration
Figure 13.7b
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Pressure Differences in the Thoracic
Cavity
 A. Normal pressure within the pleural space
is always negative (intrapleural pressure)
 B. Differences in lung and pleural space
pressures keep lungs from collapsing
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Nonrespiratory Air Movements
 A. Can be caused by reflexes or voluntary
actions
 B. Examples:
 Cough and sneeze – clears lungs of debris
 Laughing
 Crying
 Yawn
 Hiccup
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Respiratory Volumes and Capacities
 A. Normal breathing moves about 500 ml of air with
each breath (tidal volume [TV])
 B. Many factors that affect respiratory capacity
 1. A person’s size
 2. Sex
 3. Age
 4. Physical condition
 C. Residual volume of air – after exhalation, about
1200 ml of air remains in the lungs
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Respiratory Volumes and Capacities
 D. Inspiratory reserve volume (IRV)
 Amount of air that can be taken in forcibly
over the tidal volume
 Usually between 2100 and 3200 ml
 E. Expiratory reserve volume (ERV)
 Amount of air that can be forcibly exhaled
 Approximately 1200 ml
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Respiratory Volumes and Capacities
 F. Vital capacity
 The total amount of exchangeable air
 Vital capacity = TV + IRV + ERV
 G. Dead space volume
 Air that remains in conducting zone and
never reaches alveoli
 About 150 ml
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Respiratory Volumes and Capacities
 H. Functional volume
 Air that actually reaches the respiratory
zone
 Usually about 350 ml
 I. Respiratory capacities are measured with a
spirometer
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Respiratory Capacities
Figure 13.9
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