Respiratory System - riverridge210.org

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Respiratory System
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I. Functions and Development
A. The term respiration includes three
separate but related functions. 1ventilation (breathing) 2- gas exchange
3- oxygen utilization.
1. The exchange of gases (oxygen and
carbon dioxide) between the air and
blood is called external respiration.
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2. Gas exchange between the blood
and tissues is known as internal
respiration.
3. It is estimated that an adult breathes
about 9-20 times per minute, ventilating
about 5-6 liters of air during this period.
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4. If a person stops breathing,
- lose consciousness after 4-5 min.
- May suffer brain damage after 7-8 min.
- Will die after 10 min.
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B. Physical Requirements of the Respiratory
System
1. The structures through which gas is
exchanged must be thin-walled and
selectively permeable so that diffusion can
occur easily.
2. The membrane must be kept moist so that
oxygen and carbon dioxide can be dissolved
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in water to help in diffusion.
3. A rich supply of blood must be
present.
4. The surface for gas exchange must
be located deep in the body so that the
incoming air can be sufficiently warmed,
moistened, and cleansed of airborne
particles.
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5. There must be effective ventilation
mechanism to constantly replenish the
air.
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C. Functions of the Respiratory system.
1. Providing oxygen to the bloodstream
and removing carbon dioxide.
a. Gas exchange; the earth is made
up of 78% nitrogen and 21% oxygen.
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Gases
Inhaled
Exhaled
N2
O2
CO2
H2O
78.62%
20.84%
.04%
1.25%
74.9%
15.3%
3.6%
5.9%
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2. Sound production or vocalization as
expired air passes over the vocal cords.
3. Assisting in abdominal compression during
urination, defecation, and childbirth. The
abdominal muscles become more effective
during a deep breath when the air is held in
the lungs by closing the glottis and fixing the
diaphragm.
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Vocal cords
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4. Providing protection and reflexive nonbreathing.
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D. Basic Structure of the Respiratory System
1. The major passages and structures of
the respiratory system are the nasal cavity,
pharynx, larynx, trachea, bronchi,
bronchioles and alveoli within the lungs.
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Alveoli
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2. The respiratory system is frequently
divided into the conducing divisions and
respiratory divisions.
3. Conducting includes all the cavities and
structures that transport gases to and from
alveoli.
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4. The alveoli, the funcitonal units of the
system, constitute the respiratory portion.
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E. Embryological
development of the
respiratory system.
1. Cephalizationforming the head of
the baby is apparent
early in development.
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2. The formation of the nasal cavity occurs at
three and half-four weeks of embryonic
life.
3. The mouht, or oral cavity, develops at the
same time as the nasal cavity.
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4. Alveoli form about 8 weeks of
development and the supporting lung
tissue begins to form.
5. The complete structure of the lungs is not
fully developed until about 26 weeks.
(about 7 months.
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II. Conducting passages
A. Nose
1. The nose includes an external portion
that juts out from the face an internal nasal
cavity for the passage of the air.
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NOSE
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2. The nasal septum divides the nasal cavity
into: two lateral halves each are referred
to as nasal fossa.
3. Each nasal fossa opens to the nostrils or
anterior nares.
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4. Three functions that are associated with
the nasal cavity are:
a. Warming the air.
b. Smell
c. Voice
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B. Paranasal Sinuses
1. Paired air spaces in certain bones of the
skull are called paranasal sinuses. These
sinuses are named acording to the bones in
which they are formed.
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2. Maxillary, frotnal spehenoidal and
ethmoidal sinuses.
3. Each sinus has drainage ducts within the
nasal cavity on its own side.
4. Sinuses may help to warm and moisten the
air.
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5. The sinuses are also responsible for some
sound.
6. Most importantly sinuses function to
decrease the weight of the skull while
giving structural strength.
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C. Pharynx
1. The pharynx connects the nasal and
oral cavities to the larynx at the base of
the skull.
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2. The supporting walls of the pharynx are
composed of skeletal muscle, and the lumen
is lined with a mucous membrane.
3. There are sevreal paired lymphoid organs
called tonsils.
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JOKE TIME
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4. The pharynx has both respiratory and
digestive functions and speech sound.
5. The pahrynx is divided into three regions,
nasal, oral and laryngeal.
6. The nasopharynx has only respiratory
functions.
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7. It is the upper most portion of the
pharynx.
8. A penddulous uvula hangs from the
middle, lower border of the soft palate.
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9. The paired auditory, or Eustachian tube connect
the nasopharynx with the middle ear davities.
10. Pharyngeal tonsils or adenoids are inovled
during the act of swallowing. The soft palate and
uvula are elevated to block the nsasal cavity
cavity and prevent frood from entering.
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11. Sometimes a person may breath while
they are drinking, if this occurs before the
uvula blocks the nasopharynx, fluid will
come out the nose.
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12. The oropharynx is the middle portion of
the pharynx between the palate and the
level of the hyoid bone.
13. The base of the tongue forms the anterior
wall fo the oropharynx.
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14. The laryngopharynx is the lower most
portion of the pharynx.
15. The laryngopharyns is invovled in
respiratoy and digestive systems.
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D. Larynx
1. The larynx- or voice box forms the
entrance into the lower respiratory system
as it connects the laryngopharynx with the
trachea.
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2. The larynx has two main functions
a. Prevent food or fluid from entering the
trachea and lungs during swallowing.
b. Produce sound
3. It is composed of nine cartilages, three and
large single structures, and six ar paired
smaller structures
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4. The laryngeal muscles are extremely
important in closing the glottis during
swallowing and in speech.
5. There are two groups of laryngeal musclesextrinsic and intrinsic.
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6. Extrinsic muslces are responsible for
elevating the larynx during swallowing and
intrinsic muscle, when contracted change
the length, position and tension of vocal
cords.
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7. Mature males generally have thicker and
longer vocal cords than females; therefore
the vocal cords of males vibrate more
slowly and produce lower pitches.
8. The trachea, commonly called the
windpipe, is a rigid tube. It connects the
larynx to the primary bronchi.
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9. The mucosa (surface lining of the lumen)
containing many mucus-secreting goblet
cells.
10. Inhaled dust particles stick to the mucus,
and the cilia sweep it out into a cough
reflex.
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11. In some people the goblet cells over
produce mucoous and this is one reason
people might have asthma.
12. The bronchial tree is named because it is
composed of a series of respiratory tubes
as they extend into the lung.
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13. The trachea leads to a right and left
primary bronchus.
14. The borchus divides deeper in the lungs
to form secondary bronchi and segmental
bronchi.
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15. The bronchial tree continues to branch
into yet smaller tubules called bronchioles.
16. There is little cartilage in the bronchioles,
which contain thick smooth muscles that
can constrict or dialate these areas.
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18. Asthma is an infectious or allergenic
condition that invovles the bronchi. During
an asthmatic attack, there is a spasm of the
smooth muscles in the lower bronchioles.
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