Download 15-1 Checkpoint - Jordan High School

Chapter 15
Respiratory System
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15-1: The Respiratory System
Functions of the Respiratory System
Five functions:
Gas exchange between air & circulating blood
Moving air within lungs
Protect respiratory surfaces; defend against
pathogens
Produce sounds & speech
Aid in sense of smell
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Components of the Respiratory
System
Respiratory tract—passageways that
carry air to & from the lungs
Upper conducting portion
Lower respiratory portion (bronchioles & alveoli)
Respiratory mucosa lines respiratory tract
Secrete mucus; trap debris & pathogens
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15-1 Checkpoint
1. Identify the five functions of the
respiratory system.
2. What membrane lines the conducting
portion of the respiratory tract?
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15-2: Conducting Portion
The Nose
External nares open into nasal cavity
Hairs guard nasal entry from large airborne
particles
Bony hard palate forms floor of nose
Nasopharynx extends from nose to soft palate
Nasal conchae create nasal air turbulence
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The Pharynx
Three divisions:
Nasopharynx—internal nares to soft palate
Oropharynx—soft palate to back of tongue
Laryngopharynx—back of tongue to entrance
of esophagus/trachea
Materials in laryngopharynx can go either in
esophagus or trachea
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The Larynx
Air leaves the pharynx & enters the larynx
through the glottis
Epiglottis folds over the glottis to prevent
entry of liquids or foods into trachea
True vocal cords produce speech
Food/liquids touching the vocal cords trigger
coughing reflex
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Visualization of Vocal Cords
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The Trachea (windpipe)
Extends from larynx to branches of bronchi
Walls of trachea supported by tracheal
cartilages (C-shaped rings)
Prevent collapse or overexpansion of trachea
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The Bronchi
Trachea branches into right & left
primary bronchi
Primary bronchi branch into smaller airways
that form the bronchial tree
Primary bronchi  secondary bronchi 
tertiary bronchi
Bronchi end in bronchioles
Bronchodilation & bronchoconstriction change
size of bronchioles
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Bronchoscopy
Video
15-2 Checkpoint
1. The pharynx is a passageway for which
two body systems?
2. What are the vocal cords used for?
3. Why are C-shaped cartilages in the
tracheal wall better than completely
circular cartilages?
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15-3: Respiratory Tract
The Bronchioles
Each terminal bronchiole supplies air to a
lobule of the lung
Respiratory bronchioles open into alveolar
ducts that end at alveolar sacs
Surfactant on alveolar surfaces keep alveoli
open
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The Respiratory Membrane
Gas exchange occurs at the respiratory
membrane on alveolar surface
Gas exchange process:
Respiratory membranes receive blood from the
pulmonary arteries
Oxygen enters respiratory capillaries on alveoli
Arterioles meet capillaries, drop off CO2 & pick
up O2,
Venules return oxygenated blood to the heart
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The Lungs
Right lung has 3 lobes, left lung has 2 lobes
The Pleural Cavity
Each lung surrounded by a pleural cavity
Lined by parietal pleura on inside of body wall
Visceral pleura covers surface of lungs
Pleural fluid reduces friction between pleural
surfaces
A break in the pleural cavity causes a
pneumothorax (collapsed lung)
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15-3 Checkpoint
1. Trace the path of airflow from the glottis to
the respiratory membrane.
2. What would happen to the alveoli if
surfactant were not produced?
3. What are the functions of the pleural
surfaces?
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15-4: Respiration Processes
External respiration—exchange of CO2 &
O2 between body & external environment
Involves breathing, gas diffusion, & transport of
CO2 & O2
Internal respiration—absorb O2 & release
CO2 by cells
Hypoxia—low tissue O2 levels
Anoxia—supply of O2 cut off
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15-4 Checkpoint
1. Define external respiration & internal
respiration.
2. Name the steps involved in external
respiration.
3. How does hypoxia differ from anoxia?
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15-5: Pulmonary Ventilation
Pulmonary ventilation—movement of air
into & out of respiratory tract
Single breath (respiratory cycle) = inhalation
+ exhalation
Respiratory rate—number of breaths per
minute
Breathing maintains adequate alveolar
ventilation—air movement into & out of
alveoli
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Pressure & Airflow to the Lungs
Air moves from high pressure to low
pressure
Diaphragm actions:
Contraction—drops diaphragm & increases
thoracic cavity volume
Relaxation—raises diaphragm & decreases
thoracic cavity volume
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Rib cage actions:
Elevation—raises rib cage & increases thoracic
cavity volume
Depression—lowers rib cage & decreases
thoracic cavity volume
Inhalation:
Diaphragm contracts  rib cage elevates 
internal pressure drops  air rushes in
Exhalation:
Diaphragm relaxes  rib cage depresses 
internal pressure rises  air rushes out
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Lung Volumes & Lung Capacities
Tidal volume—amount of air moved into &
out of lungs in one respiratory cycle
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Expiratory reserve volume (ERV)—
amount of air that could be forcibly expelled
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Inspiratory reserve volume (IRV)—
amount of air that can be taken in above
the tidal volume
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Vital capacity—maximum amount of air
that can be moved into & out of lungs
IRV + ERV + tidal volume
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Residual volume—amount of air that
remains in lungs even after maximum
exhalation
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Typical inhalation brings in 500 mL of air
350 mL travels along conducting passageways
150 mL does not take part in gas exchange
(composes anatomical dead space)
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15-5 Checkpoint
1. Explain how the diaphragm and rib cage
cause air to move into and out of the
lungs.
2. What is tidal volume?
3. Mark breaks a rib and it punctures the
chest wall on his left side. What will
happen to his left lung?
4. How would fluid accumulation around the
alveoli affect vital capacity?
15-6: Gas Exchange
Incoming air in alveoli mixes with air in
anatomical dead space; some is exhaled
Blood in pulmonary arteries has higher CO2
& lower O2 than blood in the alveoli
Difference in gases cause CO2 to enter alveoli &
O2 to enter bloodstream
O2 diffuses from bloodstream into body
tissues
Blood returns to heart to complete cycle
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15-6 Checkpoint
1. What happens to air in the alveoli?
2. Compare the oxygen and carbon dioxide
content of the alveoli, blood in the heart,
and blood in the tissues.
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15-7: O2 & CO2 Transport
Oxygen Transport
O2 molecules carried in the blood by
hemoglobin molecules
Lower O2 content = more O2 release by
hemoglobin
O2 release also due to low pH & high body temp
Carbon monoxide (CO) poisoning—CO
binds to hemoglobin & blocks O2 from
binding
Carbon Dioxide Transport
CO2 transported:
Dissolved in plasma
Bound to hemoglobin—forms
carbaminohemoglobin
Transported as bicarbonate ions (70% of CO2
transport)
Excess CO2 molecules act as an acid in the
bloodstream & lower blood pH
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15-7 Checkpoint
1. Identify the three ways that carbon dioxide
is transported in the bloodstream.
2. As you exercise, hemoglobin releases more
oxygen to active skeletal muscles than it
does when the muscles are at rest. Why?
3. How would blockage of the trachea affect
blood pH?
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15-8: Control of Respiration
Local Control of Respiration
Active tissues increase difference in CO2 &
O2 levels causing more delivery of O2
Respiratory Centers of the Brain
Medulla oblongata & pons regulate
respiratory muscles
Control rate & depth of breathing
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Reflex Control of Respiration
Mechanoreceptors—respond to changes
in lung volume
Inflation reflex—prevents lungs from
overexpanding
Deflation reflex—stimulates inhalation when
lungs are collapsing
Chemoreceptors respond to chemical
changes in the blood
CO2 levels are responsible for regulating
respiratory activity
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Control by Higher Centers
Portions of the brain can override
respiratory centers
Control respirations during talking/singing
Hyperventilation increases rate & depth
of breathing; raises blood pH
Hypoventilation decreases rate & depth
of breathing; decreases blood pH
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15-8 Checkpoint
1. Are chemoreceptors more sensitive to
carbon dioxide or to oxygen?
2. Strenuous exercise stimulates which set of
respiratory reflexes?
3. Little Johnny tells his mother he will hold
his breath until he turns blue and dies.
Should she worry?
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