Download The Respiratory System 1

The Respiratory System
Chapter 15
Function
• Brings oxygen into the body so it can be
transported to body cells by the blood
stream
• Also removes carbon dioxide from blood
• The term respiration encompasses all
activities that transport oxygen from the
environment to the body’s cells and
carbon dioxide from the body’s cells to the
environment
Forms of Respiration
• The first is referred to as pulmonary
ventilation; accomplished by breathing in
and out—moves air between external
environment and air sacs of lungs
• External respiration — gas molecules
diffuse between air sacs and blood in
capillaries that surround them
• Internal respiration — exchange of gases
between blood and body cells
Organs of the Respiratory
System: Structural Divisions
• Structurally divided into upper and lower
respiratory system
• The upper portion includes those parts
found in the head and neck: the nose, the
pharynx, and the larynx
• The lower portion includes those parts
found mainly in the thoracic cavity: the
trachea, the bronchi, bronchioles, and the
alveoli (air sacs)
Functional Divisions
• These organs can also be divided into the
conduction zone, which conduct air toward
and away from the alveoli, and the
respiratory zone, which includes only the
alveoli and capillaries associated with
them
The Nose
• Provides an initial receiving chamber for
outside air; formed by the two nasal bones
and numerous cartilages
• Includes the external nares (nostrils) which
are separated by the nasal septum
• The small chamber that the external nares
open into is referred to as the vestibule
• The vestibules’ walls contain coarse hairs
to help remove particles from the air
Nose cont’d
• The vestibule opens into the nasal cavity
which contains nasal conchae, scroll-like
bony shelves which divide the nasal cavity
into narrow passageways called meati
• Nasal conchae maximize contact between
air and nasal cavity walls, where it can be
warmed by the nearby bloodstream
• The entire cavity is lined with mucous,
which filters and adds moisture to air
entering body
Sinuses
• Sinuses are hollow
cavities that are lined
with mucous and
connected to the nose
for drainage during
infection (sinusitis)
• Play the role of
reducing weight of the
skull and resonate
sound from the voice
Pharynx
• The pharynx is also known as the throat
• It connects the nasal cavity to the larynx
• Its walls are formed of skeletal muscle and
lined with mucous membranes
• Receives air from nasal cavity by way of
two small openings called the internal
nares
• Can be divided into three regions:
nasopharynx, oropharynx, and
laryngopharynx
• Nasopharynx receives the internal nares
and two auditory tubes which extend to the
middle ear
• Oropharynx is the region that you can see
if you look in the mirror with your mouth
wide open
• Laryngopharynx begins at base of tongue
and extends to the larynx, or voice box
• The oro- and laryngopharynx provide a
common passageway for both food and air
Larynx
• Connects the pharynx to the trachea
• Prevents solid materials from passing into
the trachea; also contains the vocal cords
for the production of sound
• Made from 9 pieces of hyaline cartilage
that form a box-like structure, including the
thyroid cartilage (enlarged in males to form
“Adam’s apple”) and epiglottic cartilage
which forms the epiglottis that channels
food and drink into the esophagus, away
from the glottis, or opening to the trachea
Vocal Cords
• The vocal cords are contained within the larynx
and are made of in-foldings of the mucous
membrane that are rich in elastic fibers
• These flaps vibrate when air is passed between
them causing sound waves
• These sound waves are converted into speech
by movement of muscles of the pharynx, jaws,
lips, and tongue which change the shape of the
openings of exhaled air, altering its sound