Transcript 13-1 Organs of Respiratory system

PowerPoint® Lecture Slide Presentation
by Patty Bostwick-Taylor,
Florence-Darlington Technical College
The Respiratory
System
13
PART A
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Organs of the Respiratory System
 Nose
 Pharynx
 Larynx
 Trachea
 Bronchi
 Lungs—alveoli
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Organs of the Respiratory System
Figure 13.1
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Functions of the Respiratory System
 Gas exchanges between the blood and external
environment
 Occurs in the alveoli of the lungs
 Passageways to the lungs purify, humidify, and warm
the incoming air
 Influences sound production and speech
 Specialized epithelium makes the sense of smell
possible
 Helps to regulate ph in the body
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Structural Plan
Upper Tract
Lower Tract
 Nose
 Trachea
 Nasopharynx
 Brachial Tree
 Oropharynx
 Lungs
 Laryngopharynx
 Alveoli
Accessory Structures:
Oral Cavity
Rib Cage
Diaphram
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The Nose
 Only externally visible part of the respiratory system
 External portion is cartilage covered by skin and
sebaceous glands
 Internal nose or nasal cavity lies over roof of mouth
 Olfactory receptors for smell are located in
the mucosa in superior part of cavity
 Rest of mucosa lining the nasal cavity is
respiratory mucosa
 Has superficial blood vessels making
nosebleeds common
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The Nose
 Cilia moves mucus posteriorly towards the
throat where it is swallowed and digested
 Effect of cold air and smoking on cilia
 Air enters the nose through the external nostrils
 Anterior nares
 Vestibule located just inside nasal cavity
 Vibrissae, course hair, are found just inside nose
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Upper Respiratory Tract
Figure 13.2
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Anatomy of the Nasal Cavity
 Lateral walls have projections called conchae
 Increase surface area
 Increase air turbulence within the nasal cavity
 Superior, middle, and inferior choncha
 Interior of the nose consists of a nasal cavity divided
by a nasal septum
 Can be deviated
 Rich supply of blood
 Nosebleeds common- called epistaxis
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Anatomy of the Nasal Cavity
 The nasal cavity is separated from the oral cavity by
the palate
 Anterior hard palate (bone)
 Consists of the palatine bones
 When bones fail to unite completely it is
called a cleft palate
 Posterior soft palate (muscle)
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Anatomy of the Nasal Cavity
 Roof of nasal cavity separated from cranial cavity by
part of ethmoid bone called cribiform plate
 Has small holes to allow olfactory nerve
(responsible for smell) to enter cranial cavity
 Can lead to infectious material entering brain
cavity
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Paranasal Sinuses
 Cavities within bones surrounding the nasal cavity are
called sinuses
 Sinuses are located in the following bones
 Frontal bone
 Sphenoid bone
 Ethmoid bone
 Maxillary bone
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Upper Respiratory Tract—Paranasal Sinuses
Figure 13.2
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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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Upper Respiratory Inflammation
 Rhinitis- inflammation of nasal mucosa
 Caused by cold viruses and allergies
 Results in nasal congestion and postnasal drip
 Since same mucosa, can spread to paranasal
sinuses
 Drippings may cause sore throat, stomach upset,
coughing or sneezing
 Treat with rest and use of antihistamines and
decongestants
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Upper Respiratory Inflammation
 Sinusitis-sinus inflammation
 Nasal passages become blocked and mucus
builds up in sinuses
 Difficult to treat
 Can result in a partial vacuum that causes a
headache
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Pharynx (Throat)
 Muscular passage from nasal cavity to larynx
 Three regions of the pharynx
 Nasopharynx—superior region behind nasal
cavity
 Oropharynx—middle region behind mouth
 Laryngopharynx—inferior region attached to
larynx
 The oropharynx and laryngopharynx are common
passageways for air and food
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Pharynx (Throat)
 Pharynx affects speech and phonation
 Only by pharynx changing shape can vowel
sounds be formed
 Continuous with the nasal cavity via the posterior
nasal aperature
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Upper Respiratory Tract: Pharynx
Figure 13.2
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Structures of the Pharynx
 Pharyngotympanic tubes from the middle ear open
into the nasopharynx
 This is why otitis media, ear infection, may follow
a sore throat
 Tonsils of the pharynx
 Pharyngeal tonsil (adenoids) are located in the
nasopharynx
 Palatine tonsils are located in the oropharynx
 Used to be commonly removed
 Lingual tonsils are found at the base of the tongue
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Structures of the Pharynx
 Pharyngitis
 Inflammation of the pharynx
 Commonly called a sore throat
 If caused by streptococcus bacteria it is called
strep throat
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Upper Respiratory Tract: Pharynx
Figure 13.2
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Larynx (Voice Box)
 Routes air and food into proper channels
 Plays a role in speech
 Made of eight rigid hyaline cartilages and a spoonshaped flap of elastic cartilage (epiglottis)
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Structures of the Larynx
 Thyroid cartilage
 Largest of the hyaline cartilages
 Protrudes anteriorly (Adam’s apple)
 Epiglottis
 Protects the superior opening of the larynx
 Routes food to the esophagus and air toward the
trachea
 When swallowing, the epiglottis rises and forms a
lid over the opening of the larynx
 Cough reflex is triggered to expel substances in
larynx
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Structures of the Larynx
 Vocal folds (true vocal cords)
 Vibrate with expelled air to create sound (speech)
 Pitch is caused diameter, length, and tension of
vocal folds
 Glottis—opening between vocal cords
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Structures of the Larynx
 Laryngitis
 Inflammation of the mucous lining of larynx
 Causes edema or vocal cords and hoarseness
 Caused by infections, inhalation of toxic fumes,
vocal abuse, and alcohol inhalation
 Can progress into croup which causes difficulty
breathing
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Upper Respiratory Tract: Larynx
Figure 13.2
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Trachea (Windpipe)
 Four-inch-long tube that connects larynx with bronchi
 Walls are reinforced with C-shaped hyaline cartilage
 Anterior is closed and posterior is open
 Lined with ciliated mucosa
 Beat continuously in the opposite direction of
incoming air
 Expel mucus loaded with dust and other debris
away from lungs to the throat so it can be
swallowed or spat out
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Trachea (Windpipe)
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Trachea (Windpipe)
Figure 13.3a
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Trachea (Windpipe)
Figure 13.3b
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Tracheal Obstruction
 Is life-threatening, can lead to death by asphyxiation
 If they can cough or make sound, leave them alone
 Heimlich maneuver used to dislodge items in airway
 Sometimes emergency tracheostomy needs to be
done
 Tracheotomy is the name of the actual incision
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Main (Primary) Bronchi
 Formed by division of the trachea
 Enters the lung at the hilum (medial depression)
 Right bronchus is wider, shorter, and straighter than
left
 Bronchi subdivide into smaller and smaller branches
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Main Bronchi
Figure 13.1
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Main Bronchi
Figure 13.4b
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Lungs
 Occupy most of the thoracic cavity
 Heart occupies central portion called mediastinum
 Apex is near the clavicle (superior portion)
 Base rests on the diaphragm (inferior portion)
 Each lung is divided into lobes by fissures
 Left lung—two lobes; horizontal fissure
 Right lung—three lobes; horizontal and oblique
fissure
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Lungs
Figure 13.4a
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Lungs
Figure 13.4b
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Coverings of the Lungs
 Serosa covers the outer surface of the lungs
 Pulmonary (visceral) pleura covers the lung
surface
 Parietal pleura lines the walls of the thoracic
cavity
 Pleural fluid fills the area between layers of pleura to
allow gliding
 These two pleural layers resist being pulled apart
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Covering of the Lungs
 Pleurisy- inflammation of the pleura
 Plural surfaces become dry and causes friction
when breathing
 Can also be caused when pleura produces an
excessive amount of fluid which exerts pressure
on the lungs
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Lungs
Figure 13.4a
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Bronchial (Respiratory) Tree Divisions
 All but the smallest of these passageways have
reinforcing cartilage in their walls
 Primary bronchi
 Secondary bronchi
 Tertiary bronchi
 Bronchioles
 Terminal bronchioles-lead to the respiratory zone
where gas exchange takes place
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Bronchial (Respiratory) Tree Divisions
Figure 13.5a
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Respiratory Zone
 Structures
 Respiratory bronchioles
 Alveolar ducts-stem
 Alveolar sacs-each cluster of grapes
 Alveoli (air sacs)-each grape
 Site of gas exchange = alveoli only
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Bronchial (Respiratory) Tree Divisions
Figure 13.5a
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Bronchial (Respiratory) Tree Divisions
Figure 13.5b
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Respiratory Membrane (Air-Blood Barrier)
 Thin squamous epithelial layer lines alveolar walls
 Alveolar pores connect neighboring air sacs
 Pulmonary capillaries cover external surfaces of
alveoli
 On one side of the membrane is air and on the other
side is blood flowing past
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Respiratory Membrane (Air-Blood Barrier)
Figure 13.6 (1 of 2)
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Respiratory Membrane (Air-Blood Barrier)
Figure 13.6 (2 of 2)
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Gas Exchange
 Gas crosses the respiratory membrane by diffusion
 Oxygen enters the blood
 Carbon dioxide enters the alveoli
 Alveolar macrophages (“dust cells”) add protection by
picking up bacteria, carbon particles, and other debris
 Surfactant (a lipid molecule) coats gas-exposed
alveolar surfaces
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Four Events of Respiration
 Pulmonary ventilation—moving air in and out of the
lungs (commonly called breathing)
 External respiration—gas exchange between
pulmonary blood and alveoli
 Oxygen is loaded into the blood
 Carbon dioxide is unloaded from the blood
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External Respiration
Figure 13.6 (2 of 2)
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Four Events of Respiration
 Respiratory gas transport—transport of oxygen and
carbon dioxide via the bloodstream
 Internal respiration—gas exchange between blood
and tissue cells in systemic capillaries
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Mechanics of Breathing
(Pulmonary Ventilation)
 Completely mechanical process that depends on
volume changes in the thoracic cavity
 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)
 Two phases
 Inspiration = inhalation
 flow of air into lungs
 Expiration = exhalation
 air leaving lungs
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Inspiration
 Diaphragm and external intercostal muscles contract
 The size of the thoracic cavity increases
 External air is pulled into the lungs due to
 Increase in intrapulmonary volume
 Decrease in gas pressure
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Inspiration
Figure 13.7a
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Inspiration
Figure 13.8
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Expiration
 Largely a passive process which depends on natural
lung elasticity
 As muscles relax, air is pushed out of the lungs due
to
 Decrease in intrapulmonary volume
 Increase in gas pressure
 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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Expiration
Figure 13.8
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Pressure Differences in the Thoracic Cavity
 Normal pressure within the pleural space is always
negative- called intrapleural pressure
 Differences in lung and pleural space pressures keep
lungs from collapsing
 When lung collapses it is called Atelectasis
 It is reversed by drawing air out of the interpleural
space with a chest tube
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Nonrespiratory Air (Gas) Movements
 Can be caused by reflexes or voluntary actions
 Examples:
 Cough and sneeze—clears lungs of debris
 Crying—emotionally induced mechanism
 Laughing—similar to crying
 Hiccup—sudden inspirations
 Yawn—very deep inspiration
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Nonrespiratory Air (Gas) Movements
Table 13.1
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Respiratory Volumes and Capacities
 Normal breathing moves about 500 mL of air with
each breath
 This respiratory volume is tidal volume (TV)
 Many factors that affect respiratory capacity
 A person’s size
 Sex
 Age
 Physical condition
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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
 Also called forced vital capacity
 Amount of air moved forcibly on one breath
 Lung size is relative to body size
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Respiratory Volumes and Capacities
 Expiratory reserve volume (ERV)
 Amount of air that can be forcibly exhaled
 Approximately 1200 mL
 Also called forced expired volume
 Residual volume
 Air remaining in lung after expiration
 About 1200 ml
 Increases with age due to less elasticity of lung
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Respiratory Volumes and Capacities
 Vital capacity
 The total amount of exchangeable air
 Vital capacity = TV + IRV + ERV
 Dead space volume
 Air that remains in conducting zone and never
reaches alveoli
 About 150 mL
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Respiratory Volumes and Capacities
 Functional volume
 Air that actually reaches the respiratory zone
 Usually about 350 mL
 Respiratory capacities are measured with a
spirometer
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Respiratory Volumes
Figure 13.9
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