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PowerPoint® Lecture Slide Presentation by Robert J. Sullivan, Marist College
Human Biology
RESPIRATORY SYSTEM:
EXCHANGE OF GASES
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings.
What is Human Respiration?

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The human respiratory
system allows one to obtain
oxygen, eliminate carbon
dioxide.
Breathing consists of two
phases, inspiration and
expiration


Inspiration- the process of
taking in air
Expiration- the process of
blowing out air
Human Respiratory System
Figure 10.1
Organs in the Respiratory System
STRUCTURE
FUNCTION
nose / nasal cavity
warms, moistens, & filters air as it is
inhaled
pharynx (throat)
passageway for air, leads to trachea
larynx
trachea (windpipe)
bronchi
bronchioles
alveoli
the voice box, where vocal chords are
located
keeps the windpipe "open"
trachea is lined with fine hairs called
cilia which filter air before it reaches the
lungs
two branches at the end of the trachea,
each lead to a lung
a network of smaller branches leading from
the bronchi into the lung tissue &
ultimately to air sacs
the functional respiratory units in the lung
where gases are exchanged
Lungs


Right-3 lobes
Left-2 lobes

Lungs: 2 unequal
lobes
Covered in a
membrane called
the pleura
At the bottom of the
cavity is a large, flat
muscle known as the
diaphragm.
Nose

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nasal cavity
nasal septum
mucous membrane
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mucus
cilia
olfactory receptors
Pharynx

Nasopharynx
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oropharynx
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adenoids or pharyngeal tonsils
palatine tonsils
laryngopharynx

larynx
Larynx
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voice box
larynx/o
glottis (vocal apparatus)
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vocal bands or vocal cords
Trachea

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Windpipe or airway
mucous membrane lining with cilia
smooth muscle with c-shaped cartilage
rings
divides into two branches: bronchi
no gaseous exchange
Epiglottis


oropharynx and laryngopharynx serve
as a common passageway for both food
and air
epiglottis acts as a lid or flap that
covers the larynx and trachea (airway)
so food does not enter the lungs.
Bronchi

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Bronchus, singular
c-shaped cartilage rings with smooth
muscle
each bronchi divides into bronchioles
terminate in air sacs called alveoli
Respiratory Cycle


Respiration rate is the number of
breaths per minute
Human respiration rate is controlled by
a part of the brain called the medulla

Sends signals to adjust levels of oxygen
present in your body by changing your
breathing rate
Regulation of Breathing:
Nervous System Involvement


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Respiratory center in the medulla oblongata:
establishes basic breathing pattern
Chemical receptors: monitor carbon dioxide,
hydrogen ions, and oxygen levels
Medulla: sensitive to hydrogen ions in
cerebrospinal fluid resulting from carbon
dioxide in blood
How Breathing Is Controlled

How Breathing Is Controlled
 Breathing is
controlled by the
medulla oblongata.
 The medulla
oblongata monitors
carbon dioxide in the
blood.
 As carbon dioxide
increases, nerve
impulses make the
diaphragm contract,
bringing air into the
lungs.
 The higher the
carbon dioxide level,
the stronger the
impulses.
Copyright Pearson Prentice Hall
Four Respiration Processes

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Breathing (ventilation): air in to and out of
lungs
External respiration: gas exchange
between air and blood
Internal respiration: gas exchange
between blood and tissues
Cellular respiration: oxygen use to produce
ATP, carbon dioxide as waste
Components of the Upper
Respiratory Tract
Figure 10.2
Upper Respiratory Tract Functions

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Passageway for respiration
Receptors for smell
Filters incoming air to filter larger foreign
material
Moistens and warms incoming air
Resonating chambers for voice
Components of the Lower
Respiratory Tract
Figure 10.3
Lower Respiratory Tract

Functions:
Larynx: maintains an open airway, routes food
and air appropriately, assists in sound production
 Trachea: transports air to and from lungs
 Bronchi: branch into lungs
 Lungs: transport air to alveoli for gas exchange

Gas Exchange Between the Blood
and Alveoli
Figure 10.8A
Process of Breathing: Pressure
Gradient
Inspiration/Expiration: air in/air out
 Cycle:
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Relaxed state: diaphragm and intercostal muscles
relaxed
Inspiration: diaphragm contracts, pulling muscle down,
intercostal muscles contract elevating chest wall and
expanding volume of chest, lowering pressure in
lungs, pulling in air
Expiration: muscles relax, diaphragm resumes dome
shape, intercostal muscles allow chest to lower
resulting in increase of pressure in chest and expulsion
of air
Respiratory Cycle
Figure 10.9
Measurement of Lung Function
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Lung volumes and vital capacity
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Tidal volume: volume of air inhaled and
exhaled in a single breath
Dead space volume: the air that remains in the
airways and does not participate in gas
exchange
Vital capacity: the maximal volume that can be
exhaled after maximal inhalation
Inspiratory reserve volume: the amount of air
that can be inhaled beyond the tidal volume
Measurement of Lung Function
(cont.)
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Lung volumes and vital capacity (continued)
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Expiratory reserve volume: the amount of air
that can be forcibly exhaled beyond the tidal
volume
Residual volume: the amount of air
remaining in the lungs, even after a forceful
maximal expiration
Measurement: spirometer
Measurement of Lung Capacity
Figure 10.10A
Malfunctions & Diseases of the Respiratory System
asthma
bronchitis
severe allergic reaction
characterized by the
constriction of bronchioles
inflammation of the lining of
the bronchioles
emphysema
condition in which the alveoli
deteriorate, causing the lungs
to lose their elasticity
pneumonia
condition in which the alveoli
become filled with fluid,
preventing the exchange of
gases
lung cancer
irregular & uncontrolled
growth of tumors in the lung
tissue
Fun Facts
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A person inhales and exhales fifteen times a minute,
approximately, 20,000 times a day.
Breathing in, and then out counts as one breathe.
You breathe in about a pint (one-half liter), but when
you run for a bus your rate can almost double and
you breathe more deeply and take in five time as
much air.
In 24 hours you breathe in nearly 2,200 liters of airenough to fill 30,000 coke cans. You breathe in a
third of that at night because your body is at rest.
Adult lungs hold nearly six quarts of air, it would take
about three days to drink this amount of liquid.