Respiratory
System
Chapter
#16
Chapter 16.1 Introduction

1.
2.
3.
4.
5.
Obtaining oxygen and removing carbon
dioxide are the primary functions of the
Respiratory System.
The Respiratory system includes tubes that:
Remove particles from incoming air
Help control the temperature & water
content
Produce vocal sounds
Transport air into and out of the lungs
Play an important role in the sense of smell
and blood pH
Chapter 16.2 Organs of the
Respiratory System

1.
2.
The organs of the respiratory system can
be divided into 2 groups.
Upper respiratory tract include the nose,
nasal cavity, paranasal sinuses, and
pharynx.
Lower respiratory tract (larynx, trachea,
bronchial tree, and lungs)
Nose


Two nostrils or
openings
Internal hairs that
guard against large
particles entering
the nasal cavity.
Nasal Cavity



Is a hollow space behind the nose.
The nasal septum, composed of bone and
cartilage, divides the nasal cavity into right
and left portions.
Nasal conchae are bones that curl out from
the lateral walls of the nasal cavity on each
side, dividing the cavity into passageways.
They also support the mucous membrane
that lines the nasal cavity and help increase
its surface area.
Paranasal Sinuses

1.
2.
Are air-filled spaces located within the
maxillary, frontal, ethmoid, and
sphenoid bones of the skull and
opening into the nasal cavity.
They reduce the weight of skull
They are resonant chambers that
affect the quality of the voice.
Pharynx





Or throat is behind the oral cavity and
between the nasal cavity and larynx.
It is a passageway for food traveling from the
oral cavity to the esophagus.
Passageway for air passing between the nasal
cavity and larynx.
Helps produce the sounds of speech.
Pharynx is divided into the nasopharynx,
oropharynx, laryngopharynx.
Larynx





Is an enlargement in the airway at the top of the
trachea and below the pharynx.
It conducts air in and out of the trachea and
prevents foreign objects from entering the trachea.
It houses the vocal cords. False vocal cords upper
folds they don’t produce sound. True vocal cords
lower folds that produce sound.
Glottis is a triangular slit opening between the
vocal cords. When you swallow the false vocal
cords close the glottis
Epiglottis is a flap like structure that covers the
larynx preventing food from going into the trachea.
Trachea



Or windpipe is a flexible,
cylindrical tube about 2.5 cm in
diameter and 12.5 cm long.
It extends downward in front of
the esophagus and into the
thoracic cavity where it splits
into right and left bronchi.
Has cartilage rings to prevent
the trachea from collapsing.
Bronchial Tree




Consists of branched airways leading
from the trachea to the air sacs (Alveoli)
in the lungs.
Primary bronchi right and left that
branch from the trachea at the 5th
thoracic vertebrae. These then branch
into secondary bronchi.
Bronchioles are even smaller tubes.
As the branches become smaller, there
are fewer muscle fibers in their walls.
Lungs




Are soft, spongy, cone-shaped organs
in the thoracic cavity.
The mediastinum separates the right
and left lung.
The diaphragm separates the lungs
from the abdominal organs and aids in
breathing.
The right lung (3 lobes) is larger than
the left lung (2 lobes).
16.3 Breathing Mechanism

Breathing, or ventilation is the
movement of air from outside the body
into and out of the bronchial tree and
alveoli.
Inspiration


1.
2.
3.
Inspiration or inhalation
Atmospheric pressure due to
the weight of air is the force
that moves air into the lungs.

When you breath in:
Your diaphragm contracts
(moves downward) the thoracic
cavity enlarges.
The ribs raise and elevates the
sternum
The pressure within the cavity
decreases…and the lungs fill.
Expiration


1.
2.
Expiration or exhalation
The forces responsible for normal
expiration come from the elastic recoil
of tissues and from surface tension.

When you breath out
Your diaphragm relaxes (moves
upward) the thoracic cavity
compresses.
The ribs lower and lower the sternum

1.
2.
3.
4.

Spirometry measures air volumes, revealing 4
distinct respiratory volumes.
Tidal Volume the air that enters and leaves the
lungs during one resting respiratory cycle.
Vital Capacity is the maximum amount of air a
person can exhale after taking the deepest breath
possible.
Functional Residual Capacity is the amount of air
that remain in the lungs after a resting expiration.
Total Lung Capacity- is the vital capacity + residual
capacity.
Spirometer is an instrument used to measure air
volumes. Such measurements are used to evaluate
the course of emphysema, pneumonia, and lung
cancer, conditions in which functional lung tissue is
lost.
16.4 Control of Breathing



Normal breathing is a rhythmic, involuntary
act that continues even when a person is
unconscious.
The respiratory muscles, however are under
voluntary control.
Respiratory center in the brain stem control
both inspiration and expiration it responds to
the concentrations of CO2 and pH (H+).

Hyperventilation is a condition due to a
lowered carbon dioxide concentration
followed by a rise in pH, a localized
vasoconstriction of cerebral arterioles,
which causes a decreased blood flow to
brain cells. Causing you to pass out!!!
Swimmers shouldn’t do!!
16.5 Alveolar Gas Exchange




Alveoli are microscopic air sacs clustered at the
distal ends of the narrowest respiratory tubes.
Simple squamous epithelium cells comprise the
alveoli membrane through which gases can easily
be exchanged.
O2 diffuses through the alveolar walls and enters
the blood in nearby capillaries.
CO2 diffuses from the blood within the capillaries
into the alveoli.
16.6 Gas Transport




Blood transport oxygen and carbon dioxide between
the lungs and cells.
Gases enter blood and they dissolve in the plasma or
combine chemically with blood components.
Almost all the oxygen that blood transports combines
with the iron-containing protein hemoglobin in red
blood cells.
Carbon dioxide is carried in the blood dissolved in
plasma, as part f a bicarbonate ion bound to the
amino groups of hemoglobin.





In the lungs oxygen dissolved and
combines with oxyhemoglobin.
More oxygen is released from
oxyhemoglobin in an acid environment.
The attraction of carbon monoxide to
hemoglobin is stronger than for oxygen,
therefore the person may die of hypoxia.
Carbon monoxide is toxic.
Hypoxia is the deficiency of oxygen
reaching tissue.
Work Cited




“Respiratory System”. May 23, 2007.
http://www.medem.com/MEDEM/images/AMA/ama_i
d_respiratoryinfections_lev20_respiratorysystemstruc
turedetail_01.gif
“Trachea”. May 23, 2007. http://www.asdonline.com/piceng/trachea.jpg
“Lungs”. May 23, 2007. http://www.webbooks.com/eLibrary/Medicine/Physiology/Respiratory/
bronchi_lungs.jpg
“Breathing”. May 23, 2007.
http://www.fda.gov/Fdac/graphics/1999graphics/bre
athing.gif