2015 Pearson Education Inc Organs of the Respiratory System Nose Pharynx Larynx Trachea Bronchi Lungsalveoli Figure 131 The major respiratory organs shown in relation to surrounding structures ID: 640794
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Slide1
© 2015 Pearson Education, Inc.Slide2
© 2015 Pearson Education, Inc.
Organs of the Respiratory System
Nose
Pharynx
Larynx
Trachea
Bronchi
Lungs—alveoliSlide3
Figure 13.1 The major respiratory organs shown in relation to surrounding structures.
Nasal cavity
Nostril
Larynx
Trachea
Right main
(primary)
bronchus
Right lung
Diaphragm
Left main
(primary)
bronchus
Left lung
Oral cavity
PharynxSlide4
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Functions of the Respiratory System
Gas exchanges between the blood and external environment
Occur in the alveoli of the lungs
Passageways to the lungs purify, humidify, and warm the incoming airSlide5
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The Nose
The only externally visible part of the respiratory system
Air enters the nose through the external nostrils (nares)
Interior of the nose consists of a nasal cavity divided by a nasal septumSlide6
Concept Link
© 2015 Pearson Education, Inc.Slide7
Figure 13.2b Basic anatomy of the upper respiratory tract, sagittal section.
Nasal cavity
Nasopharynx
Oropharynx
Laryngopharynx
Larynx
(b)
Detailed anatomy of the upper respiratory tract
Cribriform plate
of
ethmoid
bone
Sphenoidal
sinus
Posterior nasal
aperture
Frontal sinus
Pharyngeal tonsil
Opening of
pharyngotympanic
tube
Uvula
Palatine tonsil
Lingual tonsil
Esophagus
Trachea
Nasal conchae (superior,
middle and inferior)
Nasal meatuses (superior,
middle, and inferior)
Nasal vestibule
Nostril
Hard palate
Soft palate
Tongue
Hyoid bone
Epiglottis
Thyroid cartilage
Vocal fold
Cricoid cartilageSlide8
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The Nose
Olfactory receptors are located in the mucosa on the superior surface
The rest of the cavity is lined with respiratory mucosa, which:
Moistens air
Traps incoming foreign particlesSlide9
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The Nose
Lateral walls have projections called
conchae
Increase surface area
Increase air turbulence within the nasal cavityThe nasal cavity is separated from the oral cavity by the palateAnterior hard palate (bone)Posterior soft palate (unsupported)Slide10
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Paranasal Sinuses
Cavities within bones surrounding the nasal cavity are called
sinuses
Sinuses are located in the following bones:
FrontalSphenoidEthmoidMaxillarySlide11
Figure 13.2b Basic anatomy of the upper respiratory tract, sagittal section.
Nasal cavity
Nasopharynx
Oropharynx
Laryngopharynx
Larynx
(b)
Detailed anatomy of the upper respiratory tract
Cribriform plate
of
ethmoid
bone
Sphenoidal
sinus
Posterior nasal
aperture
Frontal sinus
Pharyngeal tonsil
Opening of
pharyngotympanic
tube
Uvula
Palatine tonsil
Lingual tonsil
Esophagus
Trachea
Nasal conchae (superior,
middle and inferior)
Nasal meatuses (superior,
middle, and inferior)
Nasal vestibule
Nostril
Hard palate
Soft palate
Tongue
Hyoid bone
Epiglottis
Thyroid cartilage
Vocal fold
Cricoid cartilageSlide12
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Paranasal Sinuses
Functions of the sinuses:
Lighten the skull
Act as resonance chambers for speech
Produce mucus that drains into the nasal cavitySlide13
Pharynx (Throat)
Muscular passage from nasal cavity to larynx
Three regions of the pharynx:
Nasopharynx
—superior region behind nasal cavity
Oropharynx—middle region behind mouthLaryngopharynx—inferior region attached to larynxThe oropharynx and laryngopharynx are common passageways for air and food
© 2015 Pearson Education, Inc.Slide14
Figure 13.2a Basic anatomy of the upper respiratory tract, sagittal section.
Pharynx
(a)
Regions of the pharynx
Nasopharynx
Oropharynx
LaryngopharynxSlide15
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Pharynx (Throat)
Pharyngotympanic tubes open into the nasopharynx
Tonsils of the pharynx
Pharyngeal tonsil (adenoid) is located in the nasopharynx
Palatine tonsils are located in the oropharynxLingual tonsils are found at the base of the tongueSlide16
Figure 13.2b Basic anatomy of the upper respiratory tract, sagittal section.
Nasal cavity
Nasopharynx
Oropharynx
Laryngopharynx
Larynx
(b)
Detailed anatomy of the upper respiratory tract
Cribriform plate
of
ethmoid
bone
Sphenoidal
sinus
Posterior nasal
aperture
Frontal sinus
Pharyngeal tonsil
Opening of
pharyngotympanic
tube
Uvula
Palatine tonsil
Lingual tonsil
Esophagus
Trachea
Nasal conchae (superior,
middle and inferior)
Nasal meatuses (superior,
middle, and inferior)
Nasal vestibule
Nostril
Hard palate
Soft palate
Tongue
Hyoid bone
Epiglottis
Thyroid cartilage
Vocal fold
Cricoid cartilageSlide17
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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 spoon-shaped flap of elastic cartilage (epiglottis)Slide18
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Larynx (Voice Box)
Thyroid cartilage
Largest of the hyaline cartilages
Protrudes anteriorly (Adam’s apple)
EpiglottisProtects the superior opening of the larynxRoutes food to the posteriorly situated esophagus and routes air toward the tracheaWhen swallowing, the epiglottis rises and forms a lid over the opening of the larynxSlide19
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Larynx (Voice Box)
Vocal folds (true vocal cords)
Vibrate with expelled air
The glottis consists of the vocal cords and the
slitlike pathway (opening)Slide20
Framework of the Larynx
Figure 22.4a, bSlide21
Movements of Vocal Cords
Figure 22.5Slide22
Sphincter Functions of the Larynx
The larynx is closed during coughing, sneezing, and Valsalva’s maneuver
Valsalva’s maneuver
Air is temporarily held in the lower respiratory tract by closing the glottis
Causes intra-abdominal pressure to rise when abdominal muscles contract
Helps to empty the rectumActs as a splint to stabilize the trunk when lifting heavy loadsSlide23
Figure 13.2b Basic anatomy of the upper respiratory tract, sagittal section.
Nasal cavity
Nasopharynx
Oropharynx
Laryngopharynx
Larynx
(b)
Detailed anatomy of the upper respiratory tract
Cribriform plate
of
ethmoid
bone
Sphenoidal
sinus
Posterior nasal
aperture
Frontal sinus
Pharyngeal tonsil
Opening of
pharyngotympanic
tube
Uvula
Palatine tonsil
Lingual tonsil
Esophagus
Trachea
Nasal conchae (superior,
middle and inferior)
Nasal meatuses (superior,
middle, and inferior)
Nasal vestibule
Nostril
Hard palate
Soft palate
Tongue
Hyoid bone
Epiglottis
Thyroid cartilage
Vocal fold
Cricoid cartilageSlide24
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Trachea (Windpipe)
4-inch-long tube that connects larynx with bronchi
Walls are reinforced with C-shaped hyaline cartilage, which keeps the trachea patent
Lined with ciliated mucosa
Cilia beat continuously in the opposite direction of incoming airExpel mucus loaded with dust and other debris away from lungsSlide25
Figure 13.3a Structural relationship of the trachea and esophagus.
Posterior
Lumen of
trachea
Anterior
Esophagus
Seromucous
gland in
submucosa
Mucosa
Trachealis
muscle
Submucosa
Hyaline
cartilage
Adventitia
(a)Slide26
Figure 13.3b Structural relationship of the trachea and esophagus.
(b)Slide27
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Main (Primary) Bronchi
Formed by division of the trachea
Each bronchus enters the lung at the hilum (medial depression)
Right bronchus is wider, shorter, and straighter than left
Bronchi subdivide into smaller and smaller branchesSlide28
Figure 13.1 The major respiratory organs shown in relation to surrounding structures.
Nasal cavity
Nostril
Larynx
Trachea
Right main
(primary)
bronchus
Right lung
Diaphragm
Left main
(primary)
bronchus
Left lung
Oral cavity
PharynxSlide29
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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 fissuresLeft lung—two lobesRight lung—three lobesSlide30
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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 to allow gliding and decrease friction during breathingPleural space (between the layers) is more of a potential spaceSlide31
Figure 13.4a Anatomical relationships of organs in the thoracic cavity.
Trachea
Thymus
Apex of lung
Right superior lobe
Horizontal fissure
Right middle lobe
Oblique fissure
Right inferior lobe
Heart
(in pericardial cavity
of mediastinum)
Diaphragm
Base of lung
Lung
Intercostal muscle
Rib
Parietal pleura
Pleural cavity
Visceral pleura
Left superior lobe
Oblique fissure
Left inferior lobe
(a)
Anterior view.
The lungs flank
mediastinal
structures laterally.Slide32
Figure 13.4b Anatomical relationships of organs in the thoracic cavity.
(b)
Transverse section through the thorax, viewed from above.
Sternum
Pericardial
membranes
Pleural cavity
Visceral pleura
Parietal pleura
Right lung
Vertebra
Posterior
Esophagus
(in posterior mediastinum)
Root of lung at hilum
Left main bronchus
Left pulmonary artery
Left pulmonary vein
Left lung
Thoracic wall
Pulmonary trunk
Heart (in mediastinum)
Anterior mediastinum
AnteriorSlide33
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Bronchial (Respiratory) Tree Divisions
All but the smallest of these passageways have reinforcing cartilage in their walls
Conduits to and from the respiratory zone
Primary bronchi
Secondary bronchiTertiary bronchiBronchiolesTerminal bronchiolesSlide34Slide35
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Respiratory Zone Structures
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli (air sacs)Slide36
Figure 13.5a Respiratory zone structures.
Alveolar duct
Respiratory
bronchioles
Terminal
bronchiole
(a)
Diagrammatic view of respiratory
bronchioles, alveolar ducts, and alveoli
Alveoli
Alveolar duct
Alveolar
sacSlide37
Figure 13.5b Respiratory zone structures.
Alveolar
duct
Alveolar
pores
Alveolus
(b)
Light micrograph of human lung tissue,
showing the final divisions of the
respiratory tree (120×)Slide38
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The Respiratory Membrane
Thin squamous epithelial layer lines alveolar walls
Alveolar pores connect neighboring air sacs
Pulmonary capillaries cover external surfaces of alveoli
Respiratory membrane (air-blood barrier) On one side of the membrane is air, and on the other side is blood flowing past Formed by alveolar and capillary wallsSlide39
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The Respiratory Membrane
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 debrisSurfactant (a lipid molecule) coats gas-exposed alveolar surfacesSlide40
Figure 13.6 Anatomy of the respiratory membrane (air-blood barrier).Slide41
Figure 13.6 Anatomy of the respiratory membrane (air-blood barrier).
Endothelial cell
nucleus
Alveolar pores
Capillary
Macrophage
Nucleus of
squamous
epithelial cell
Alveoli (gas-
filled air
spaces)
Red blood
cell in
capillary
Surfactant-
secreting cell
Squamous
epithelial cell
of alveolar wall
Red blood cell
Capillary
Alveolus
Alveolar epithelium
Fused basement
membranes
Capillary endothelium
CO
2
O
2
Respiratory
membraneSlide42
Respiratory Membrane
Figure 22.9bSlide43
Four Events of Respiration
Pulmonary ventilation—moving air into and out of the lungs (commonly called
breathing
)
External respiration—gas exchange between pulmonary blood and alveoli
Oxygen is loaded into the bloodCarbon dioxide is unloaded from the blood
© 2015 Pearson Education, Inc.Slide44
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
© 2015 Pearson Education, Inc.Slide45
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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 pressureSlide46
Concept Link
© 2015 Pearson Education, Inc.Slide47
© 2015 Pearson Education, Inc.
Mechanics of Breathing (Pulmonary Ventilation)
Two phases
Inspiration = inhalation
Flow of air into lungs
Expiration = exhalationAir leaving lungsSlide48
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Mechanics of Breathing (Pulmonary Ventilation)
Inspiration
Diaphragm and external intercostal muscles contract
The size of the thoracic cavity increases
External air is pulled into the lungs as a result of: Increase in intrapulmonary volumeDecrease in gas pressureAir is sucked into the lungsSlide49
Figure 13.7a Rib cage and diaphragm
positions during breathing.
Changes in anterior-posterior and
superior-inferior dimensions
Changes in lateral
dimensions
Ribs elevated
as external
intercostals
contract
External
intercostal
muscles
Diaphragm moves
inferiorly during
contraction
Full inspiration
(External
intercostals
contract)
(a)
Inspiration: Air (gases) flows into the lungsSlide50
Figure 13.8 Changes in intrapulmonary pressure and air flow during inspiration
and expiration.
+2
+1
0
−1
−2
0.5
0
−0.5
Inspiration
Expiration
Intrapulmonary
pressure
Pressure relative
to atmospheric pressure
(a)
Volume (L)
Volume of
breath
(b)Slide51
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Mechanics of Breathing (Pulmonary Ventilation)
Expiration
Largely
a passive process that depends on natural lung
elasticityAs muscles relax, air is pushed out of the lungs as a result of:Decrease in intrapulmonary volumeIncrease in gas pressure
Forced expiration can occur mostly by contraction of internal intercostal muscles to depress the rib cageSlide52
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Mechanics of Breathing (Pulmonary Ventilation)
Normal pressure within the pleural space is always negative (intrapleural pressure)
Differences in lung and pleural space pressures keep lungs from collapsing
Atelectasis is collapsed lung
Pneumothorax is the presence of air in the intrapleural spaceSlide53
Figure 13.7b Rib cage and diaphragm
positions during breathing.
(b)
Expiration: Air (gases) flows out of the lungs
Expiration
(External
intercostals
relax)
Ribs depressed
as external
intercostals
relax
External
intercostal
muscles
Diaphragm moves
superiorly as
it relaxes
Changes in anterior-posterior and
superior-inferior dimensions
Changes in lateral
dimensionsSlide54
Figure 13.8 Changes in intrapulmonary pressure and air flow during inspiration
and expiration.
+2
+1
0
−1
−2
0.5
0
−0.5
Inspiration
Expiration
Intrapulmonary
pressure
Pressure relative
to atmospheric pressure
(a)
Volume (L)
Volume of
breath
(b)Slide55
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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 affect respiratory capacity
A person’s sizeSexAgePhysical conditionSlide56
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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 around 3,100 ml
Expiratory reserve volume (ERV)Amount of air that can be forcibly exhaled after a tidal expirationApproximately 1,200 mlSlide57
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Respiratory Volumes and Capacities
Residual volume
Air remaining in lung after expiration
Allows gas exchange to go on continuously, even between breaths, and helps keep alveoli open (inflated)
About 1,200 mlSlide58
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Respiratory Volumes and Capacities
Vital capacity
The total amount of exchangeable air
Vital capacity = TV + IRV + ERV
4,800 ml in men; 3,100 ml in womenDead space volumeAir that remains in conducting zone and never reaches alveoliAbout 150 mlSlide59
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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 spirometerSlide60
Figure 13.9
Idealized tracing of the various respiratory volumes of a healthy young adult male.
0
1,000
2,000
3
,000
4,000
5,000
6,000
Milliliters (ml)
Inspiratory
reserve volume
3,100 ml
Tidal volume 500 ml
Expiratory
reserve
v
olume
1,200 ml
Residual volume
1,200 ml
Vital
capacity
4,800 ml
Total lung
capacity
6,000 mlSlide61
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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 inspirationsYawn—very deep inspirationSlide62
Table 13.1
Nonrespiratory
Air (Gas)
MovementsSlide63
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Respiratory Sounds
Sounds are monitored with a stethoscope
Two recognizable sounds can be heard with a stethoscope:
Bronchial sounds—produced by air rushing through large passageways such as the trachea and bronchi
Vesicular breathing sounds—soft sounds of air filling alveoliSlide64
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External Respiration, Gas Transport, and Internal Respiration
Gas exchanges occur as a result of diffusion
Movement of the gas is toward the area of lower concentrationSlide65
Figure 13.10 Gas
exchanges in the body occur according to the laws of diffusion.
O
2
CO
2
CO
2
O
2
CO
2
O
2
O
2
CO
2
CO
2
O
2
CO
2
O
2
CO
2
O
2
Inspired air:
Alveoli
of lungs:
External
respiration
Pulmonary
arteries
Alveolar
capillaries
Pulmonary
veins
Blood
leaving
lungs and
entering
tissue
capillaries:
Blood
leaving
tissues and
entering
lungs:
Heart
Tissue
capillaries
Systemic
veins
Internal
respiration
Systemic
arteries
Tissue
cells:Slide66
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External Respiration
Oxygen is loaded into the blood
The alveoli always have more oxygen than the blood
Oxygen moves by diffusion towards the area of lower concentration
Pulmonary capillary blood gains oxygenSlide67
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External Respiration
Carbon dioxide is unloaded out of the blood
Blood returning from tissues has higher concentrations of carbon dioxide than air in the alveoli
Pulmonary capillary blood gives up carbon dioxide to be exhaled
Blood leaving the lungs is oxygen rich and carbon dioxide poorSlide68
Figure 13.11a
Diagrammatic representation of the major means of oxygen (O
2
) and carbon dioxide (CO
2
) loading and unloading in the body.
CO
2
O
2
Hb
+ O
2
HbO
2
HCO
3
−
+ H
+
H
2
CO
3
CO
2+ H2O
(a)
External respiration in the lungs
(pulmonary gas exchange)
Oxygen is loaded into the bloodand carbon dioxide is unloaded.
Alveoli (air sacs)
Loading
of O
2
Unloading
of CO
2
(
Oxyhemoglobin
is formed)
Bicar
-
bonate
ion
Carbonic
acid
Water
Plasma
Red blood cell
Pulmonary capillarySlide69
Gas Transport in the Blood
Oxygen transport in the blood
Most oxygen travels attached to hemoglobin and forms oxyhemoglobin (HbO
2
)
A small dissolved amount is carried in the plasma© 2015 Pearson Education, Inc.Slide70
Figure 13.11a
Diagrammatic representation of the major means of oxygen (O
2
) and carbon dioxide (CO
2
) loading and unloading in the body.
CO
2
O
2
Hb
+ O
2
HbO
2
HCO
3
−
+ H
+
H
2
CO
3
CO
2+ H2O
(a)
External respiration in the lungs
(pulmonary gas exchange)
Oxygen is loaded into the bloodand carbon dioxide is unloaded.
Alveoli (air sacs)
Loading
of O
2
Unloading
of CO
2
(
Oxyhemoglobin
is formed)
Bicar
-
bonate
ion
Carbonic
acid
Water
Plasma
Red blood cell
Pulmonary capillarySlide71
Gas Transport in the Blood
Carbon dioxide transport in the blood
Most carbon dioxide is transported in the plasma as bicarbonate ion (HCO
3
–
)A small amount is carried inside red blood cells on hemoglobin, but at different binding sites from those of oxygen© 2015 Pearson Education, Inc.Slide72
Concept Link
© 2015 Pearson Education, Inc.Slide73
Gas Transport in the Blood
For carbon dioxide to diffuse out of blood into the alveoli, it must be released from its bicarbonate form:
Bicarbonate ions enter RBC
Combine with hydrogen ions
Form carbonic acid (H
2CO3)Carbonic acid splits to form water + CO2Carbon dioxide diffuses from blood into alveoli
© 2015 Pearson Education, Inc.Slide74
Figure 13.11a
Diagrammatic representation of the major means of oxygen (O
2
) and carbon dioxide (CO
2
) loading and unloading in the body.
CO
2
O
2
Hb
+ O
2
HbO
2
HCO
3
−
+ H
+
H
2
CO
3
CO
2+ H2O
(a)
External respiration in the lungs
(pulmonary gas exchange)
Oxygen is loaded into the bloodand carbon dioxide is unloaded.
Alveoli (air sacs)
Loading
of O
2
Unloading
of CO
2
(
Oxyhemoglobin
is formed)
Bicar
-
bonate
ion
Carbonic
acid
Water
Plasma
Red blood cell
Pulmonary capillarySlide75
Internal Respiration
Exchange of gases between blood and body cells
An opposite reaction to what occurs in the lungs
Carbon dioxide diffuses out of tissue to blood (called
loading
)Oxygen diffuses from blood into tissue (called unloading)© 2015 Pearson Education, Inc.Slide76
Figure 13.11b
Diagrammatic representation of the major means of oxygen (O
2
) and carbon dioxide (CO
2
) loading and unloading in the body.
CO
2
+H
2O
H
2
CO
3
H
+
+ HCO
3
−
HbO
2
Hb
+ O2
CO2
O2
(b)
Internal respiration in the body tissues
(systemic capillary gas exchange)
Oxygen is unloaded and carbondioxide is loaded into the blood.
Plasma
Systemic capillary
Red blood cell
Loading
of CO
2
Unloading
of O
2
Tissue cells
Water
Carbonic
acid
Bicar
-
bonate
ionSlide77
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Neural Regulation of Respiration
Activity of respiratory muscles is transmitted to and from the brain by phrenic and intercostal nerves
Neural centers that control rate and depth are located in the medulla and pons
Medulla—sets basic rhythm of breathing and contains a pacemaker (self-exciting inspiratory center) called the
ventral respiratory group
(VRG)Pons—appears to smooth out respiratory rateSlide78
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Neural Regulation of Respiration
Normal respiratory rate (
eupnea
)
12 to 15 respirations per minuteHyperpneaIncreased respiratory rate, often due to extra oxygen needsSlide79
Figure 13.12
Breathing control centers, sensory inputs, and effector nerves.
Breathing control centers:
Pons centers
Medulla centers
Afferent
impulses to
medulla
Breathing control centers
stimulated by:
CO
2
increase in blood
(acts directly on medulla
centers by causing a
drop in pH of CSF)
Nerve impulse
from O
2
sensor
indicating O
2
decrease
CSF in
brain
sinus
O
2
sensor
in aortic bodyof aortic arch
Intercostal
muscles
Diaphragm
Efferent nerve impulses from
medulla trigger contraction
of inspiratory muscles.
Phrenic nerves
Intercostal nervesSlide80
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Non-Neural Factors Influencing Respiratory Rate and Depth
Physical factors
Increased body temperature
Exercise
TalkingCoughingVolition (conscious control)Emotional factors such as fear, anger, and excitementSlide81
Non-Neural Factors Influencing Respiratory Rate and Depth
Chemical factors: CO
2
levels
The body’s need to rid itself of CO
2 is the most important stimulus for breathingIncreased levels of carbon dioxide (and thus, a decreased or acidic pH) in the blood increase the rate and depth of breathingChanges in carbon dioxide act directly on the medulla oblongata
© 2015 Pearson Education, Inc.Slide82
Non-Neural Factors Influencing Respiratory Rate and Depth
Chemical factors: oxygen levels
Changes in oxygen concentration in the blood are detected by chemoreceptors in the aorta and common carotid artery
Information is sent to the medulla
Oxygen is
the stimulus for those whose systems have become accustomed to high levels of carbon dioxide as a result of disease© 2015 Pearson Education, Inc.Slide83
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Non-Neural Factors Influencing Respiratory Rate and Depth
Chemical factors
Hyperventilation
Rising levels of CO
2 in the blood (acidosis) result in faster, deeper breathingBlows off more CO2 to restore normal blood pHMay result in apnea and dizziness and lead to alkalosisSlide84
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Non-Neural Factors Influencing Respiratory Rate and Depth
Chemical factors
Hypoventilation
Results when blood becomes alkaline (alkalosis)
Extremely slow or shallow breathingAllows CO2 to accumulate in the bloodSlide85
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Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD)
Exemplified by chronic bronchitis and emphysema
Major causes of death and disability in the United StatesSlide86
Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD)
Features of these diseases
Patients almost always have a history of smoking
Labored breathing (dyspnea) becomes progressively more severe
Coughing and frequent pulmonary infections are common
© 2015 Pearson Education, Inc.Slide87
Respiratory Disorders: Chronic Obstructive Pulmonary Disease (COPD)
Features of these diseases (
continued
)
Most victims are hypoxic, retain carbon dioxide, and have respiratory acidosis
Those who acquire infections will ultimately develop respiratory failure© 2015 Pearson Education, Inc.Slide88
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Respiratory Disorders: Chronic Bronchitis
Mucosa of the lower respiratory passages becomes severely inflamed
Excessive mucus production impairs ventilation and gas exchange
Patients become cyanotic and are sometimes called “blue bloaters” as a result of chronic hypoxia Slide89
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Respiratory Disorders: Emphysema
Alveoli permanently enlarge as adjacent chambers break through and are destroyed
Chronic inflammation promotes lung fibrosis, and lungs lose elasticity
Patients use a large amount of energy to exhale as exhalation becomes an active process
Overinflation of the lungs leads to a permanently expanded barrel chestCyanosis appears late in the disease; sufferers are often called “pink puffers”Slide90
Figure 13.13
The pathogenesis of COPD.
Tobacco smoke
Air pollution
Continual bronchial
irritation and
inflammation
Breakdown of elastin
in connective tissue
of lungs
Emphysema
Chronic bronchitis
Excessive mucus
produced,
Chronic productive
cough
Destruction of
alveolar walls
Loss of lung elasticity
Airway obstruction
or air trapping
Dyspnea
Frequent infections
Respiratory
failureSlide91
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Lung Cancer
Extremely aggressive and metastasizes rapidly
Accounts for one-third of all U.S. cancer deaths
Increased incidence is associated with smoking
Three common types:Squamous cell carcinomaAdenocarcinoma
Small cell carcinomaSlide92
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Developmental Aspects of the Respiratory System
Premature infants have problems keeping their lungs inflated because of a lack of surfactant in their alveoli. (Surfactant is formed late in pregnancy
around 28 to 30 weeks of pregnancy)
Infant respiratory distress syndrome (IRDS)—surfactant production is inadequateSlide93
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Developmental Aspects of the Respiratory System
Significant birth defects affecting the respiratory system:
Cleft palate
Cystic fibrosis—oversecretion of thick mucus clogs the respiratory systemSlide94
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Developmental Aspects of the Respiratory System
Respiratory rate changes throughout life
Newborns: 40 to 80 respirations per minute
Infants: 30 respirations per minute
Age 5: 25 respirations per minuteAdults: 12 to 18 respirations per minuteRate often increases somewhat with old ageSlide95
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Developmental Aspects of the Respiratory System
Sudden infant death syndrome (SIDS)
Apparently healthy infant stops breathing and dies during sleep
Some cases are thought to be a problem of the neural respiratory control center
One-third of cases appear to be due to heart rhythm abnormalitiesRecent research shows a genetic componentSlide96
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Developmental Aspects of the Respiratory System
Asthma
Chronically inflamed hypersensitive bronchiole passages
Respond to irritants with dyspnea, coughing, and wheezingSlide97
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Developmental Aspects of the Respiratory System
During youth and middle age, most respiratory system problems are a result of external factors, such as infections and substances that physically block respiratory passagewaysSlide98
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Developmental Aspects of the Respiratory System
Aging effects
Elasticity of lungs decreases
Vital capacity decreases
Blood oxygen levels decreaseStimulating effects of carbon dioxide decreaseElderly are often hypoxic and exhibit sleep apneaMore risks of respiratory tract infection