Transcript Respiratory Membrane - Mount Carmel Academy

Chapter 13 – Part 1
The Respiratory System
Organs of the Respiratory system
 Nose
 Pharynx
 Larynx
 Trachea
 Bronchi
 Lungs –
alveoli
Function of the Respiratory System
 Oversees gas exchanges between the
blood and external environment
 Exchange of gasses takes place within
the lungs in the alveoli
 Passageways to the lungs purify, warm,
and humidify the incoming air
The Nose
 The only externally
visible part of the
respiratory system
 Air enters the nose through
the external nares (nostrils)
 The interior of the nose consists of a
nasal cavity divided by a nasal
septum
Figure 13.2
Anatomy of the Nasal Cavity
 Olfactory receptors for the sense of
smell are located in the mucosa on the
slitlike superior part of the nasal cavity
 The rest of the cavity is lined with
respiratory mucosa
 Warm the air
 Moistens the air
 Traps incoming foreign particles (cleanse)
Anatomy of the Nasal Cavity
 The ciliated cells of the nasal
mucosa create a gentle current
that moves contaminated mucous
posteriorly towards the throat (pharynx)
 It is then swallowed and digested by stomach
juices.
 When it is extremely cold, these cilia become
sluggish, allowing mucus to accumulate in
the nasal cavity and to dribble outward
through the nostrils.
 This is why you have a “runny” nose on a cold
day.
Nosebleeds
 The respiratory mucosa
rests on a rich network of
thin-walled veins (warms
the air as it flows by).
 Because of the
superficial location of
these blood vessels,
nosebleeds are
common and often
profuse.
Anatomy of the Nasal Cavity
 The lateral walls of the nasal
cavity have three projections
or lobes called conchae
 Increases surface area
 Increases air turbulence within
the nasal cavity
 Helps to deflect inhaled particles onto the
mucus-coated surfaces, where they are
trapped and prevented from entering the
lungs.
Anatomy of the Nasal Cavity
 The nasal cavity is separated from the
oral cavity by the palate
 Anterior hard palate (bone)
 Posterior soft palate (muscle)
Cleft Palate
 Cleft palate – The bones forming the
palate fail to fuse medially
 Genetic defect
 Results in breathing difficulties and
problems with oral cavity functions
(chewing and speaking)
Paranasal Sinuses
 The nasal cavity is surrounded by a ring
of paranasal sinuses.
 Are located in the:
 Frontal bone
 Sphenoid bone
 Ethmoid bone
 Maxillary bone
Paranasal Sinuses
 Function of the sinuses
1. Lighten the skull
2. Act as resonance chambers for speech
3. Produce mucus that drains into the nasal
cavity
•
The suctioning effect created by nose
blowing helps to drain the sinuses.
•
The nasolacrimal ducts, which drain
tears from the eyes, also empty into
the nasal cavities
Sinusitis
 Sinusitis – sinus inflammation
 Difficult to treat
 Can cause marked changes in voice
quality
 When the passageways connecting the
sinuses to the nasal cavity are blocked
with mucus or infectious matter, the air in
the sinus cavities is absorbed
 The result is a partial vacuum and a sinus
headache
Pharynx (Throat)
 Pharynx - Muscular
passage from nasal
cavity to larynx
 About 5 inches long
 Commonly called the throat
 Serves as a common passageway for
food and air
 Is continuous with the nasal cavity
anteriorly via the internal nares
Pharynx (Throat)
 Three regions of the
pharynx:
 Nasopharynx – superior
region behind nasal cavity
 Oropharynx – middle region behind mouth
 Laryngopharynx – inferior region attached
to larynx
 The oropharynx and laryngopharynx are
common passageways for air and food
 Air then passes through the larynx, while food
is directed into the esophagus posteriorly
Structures of the Pharynx
 The auditory tubes,
which drain the middle
ear, open into the
nasopharynx
 Since the mucosae of
these two regions are
continous, ear infections
may follow a sore throat
or other types of
pharyngeal infections
Structures of the Pharynx
 Tonsils (clusters of lymphatic
tissue) are also found in the
pharynx
 Their job is to trap and remove any bacteria
or other foreign pathogens entering the
throat
 Pharyngeal tonsil – located high in the
nasopharynx
 Palatine tonsils – located in the oropharynx at
the end of the soft palate
 Lingual tonsils – located at the base of the
tongue
Tonsillitis
 Tonsillitis – Inflammation and swelling of
the pharyngeal tonsil
 Can occur during a bacterial infection
 It obstructs the nasopharnyx and forces the
person to breathe through the mouth
 In mouth breathing, air is not properly moistened,
warmed, or filtered before entering the lungs
 Years ago, the belief was that the tonsils were
more trouble than they were worth and they
were routinely removed.
 Now, this is no longer necessary because of the
large use of antibiotics
Larynx (Voice Box)
 Functions of the Larynx:
1. Routes air and food
into proper channels
2. Plays a role in speech
(voice production)
3. Acts as an airway
 Made of eight rigid hyaline cartilages
and a spoon-shaped flap of elastic
cartilage (epiglottis)
Structures of the Larynx
 Thyroid cartilage
 Largest hyaline
cartilage
 Shield-shaped
 Protrudes
anteriorly
 Commonly called
the Adam’s apple
Structures of the Larynx
 Epiglottis
 Protects the superior
opening of the larynx
 Routes food to the esophagus
and air toward the trachea
 The epiglottis moves positions when swallowing
 When we are not swallowing: the epiglottis does
not restrict the passage of air into the lower
respiratory passages
 When we are swallowing: the larynx is pulled
upward and the epiglottis tips, forming a lid over
the opening of the larynx; this routes food into the
esophagus
Structures of the Larynx
 Palpate your larynx by placing your
hand midway on the anterior surface of
your neck. Swallow. Can you feel the
larynx rising as you swallow?
Cough Reflex
 If anything other than air
enters the larynx, a cough
reflex is triggered to expel
the substance and to prevent it from
continuing into the lungs.
 Because this protective reflex does not
work when we are unconscious, it is never
a good idea to try to give fluids to an
unconscious person when attempting to
revive him or her.
Structures of the Larynx
 Vocal cords (vocal folds)
 Pair of folds
 Vibrate with expelled air to
create sound
 Allows us to speak
 Glottis – the slitlike
passageway between the
vocal cords
Trachea (Windpipe)
 Connects larynx with bronchi
 About 4 inches long
 Lined with ciliated mucosa
 Beat continuously in the opposite direction of
incoming air
 Propels mucus loaded with dust and other
debris away from lungs to the throat, where it
can be swallowed or spat out
The Trachea and Smoking
 Smoking inhibits
ciliary activity and
ultimately destroys
the cilia
 Without these cilia,
coughing is the
only means of
preventing mucus
from accumulating
in the lungs
Trachea (Windpipe)
 The trachea is fairly rigid
because its walls are reinforced
with C-shaped hyaline cartilage
 These rings form two purposes:
1. Support the trachea and keep it
open in spite of the pressure
changes that occur during
breathing
2. Allows it to expand anteriorly
when we swallow a large piece of
food
Heimlich Maneuver
 Heimlich maneuver – a
procedure in which the air in
a person’s own lungs is used
to “pop out,” or expel, an
obstructing piece of food
 Because the trachea is the only way air can get
into the lungs, tracheal obstruction is lifethreatening
 Many people have suffocated after choking on a
piece of food that suddenly closed off the trachea
 Has saved many people from choking to death
Primary Bronchi
 The right and left primary bronchi is formed by
the division of the trachea
 Enters the lung at the hilus (medial depression)
 Right bronchus is wider, shorter, and straighter
than left
 Consequently it is the more common site for an
inhaled foreign object to become lodged
 Bronchi subdivide into smaller and smaller
branches
 By the time air enters the bronchi, it is warmed,
cleansed of most impurities, and well humidified
Lungs
 The paired lungs are fairly
large organs
 Occupy most of the thoracic
cavity
 Apex is near the clavicle
(narrow, superior portion)
 The broad base rests on
the diaphragm (inferior
portion)
 The bronchi enters the lung
at the hilus (medial depression)
Lungs
 Each lung is
divided into lobes
by fissures
 Left Lung Has two lobes
 Right Lung Has three
lobes
Coverings of the Lungs
 Pulmonary (visceral)
pleura covers the lung
surface
 Parietal pleura lines the
walls of the thoracic cavity
 Pleural fluid fills the area between
layers of pleura to allow gliding during
breathing movements
 Can slide easily from side to side across
one another, but resists being pulled apart.
Lungs
Coverings of the Lungs
 Pleurisy – Inflammation of the pleura
 Can be caused by the decreased
secretion of pleural fluid
 The pleural surfaces become dry and
rough
 Results in friction and stabbing pain
with each breath
Respiratory Tree Divisions
 This branching and rebranching within the
lungs is often referred to as the bronchial
or respiratory tree:
1. Primary bronchi
2. Secondary
bronchi
3. Tertiary bronchi
4. Bronchioles
5. Terminal
bronchioles
Bronchioles
 Bronchioles - Smallest
branches of the bronchi
 All but the smallest
branches have
reinforcing cartilage
Bronchioles
 Terminal
bronchioles end
in alveoli, or air
sacs.
Respiratory Zone
 The respiratory zone is the only site of gas
exchange
 Includes the following structures:
 Respiratory bronchioles
 Alveolar ducts
 Alveolar sacs
 Alveoli
 All other respiratory passages are
conducting zone structures
 Serve as conduits to and from the respiratory
zone.
Alveoli
 There are millions of
the clustered alveoli,
which resemble
bunches of grapes.
 They make up the bulk of the lungs
 Consequently, the lungs are mostly air
space
 In spite of their relatively large size, the
lungs weigh only about 2 ½ pounds, and
they are soft and spongy
Alveoli
 Structure of alveoli
 Alveolar duct
 Alveolar sac
 Alveoli
 Gas exchange takes place within the alveoli
in the respiratory membrane
Alveoli
 Structure of alveoli
 Alveolar duct
 Alveolar sac
 Alveoli
 Gas exchange takes place within the alveoli
in the respiratory membrane
Respiratory Membrane
 Respiratory Membrane
(Air-Blood Barrier) –
Has gas (air) flowing
past on one side and
blood flowing past on
the other
 Made up of the alveolar
and capillary walls and
their fused basement
membranes.
Respiratory Membrane
 The walls of the alveoli are
composed largely of a single,
thin layer of squamous
epithelial cells
 The thinness of their walls is
hard to imagine, but a sheet of
tissue paper is much thicker
 The external surfaces of the
alveoli are covered with a
“cobweb” of pulmonary
capillaries
Respiratory Membrane
 Alveolar pores
connect neighboring
air sacs and provide
alternate routes for
air to reach alveoli
 In case feeder
bronchioles have
been clogged by
mucus or
otherwise blocked
Gas Exchange
 Gas exchanges occur by simple diffusion
through the respiratory membrane
 Oxygen enters the blood
 Carbon dioxide enters the alveoli
 The total gas exchange surface provided by
the alveolar walls is 40 times greater than
the surface of your skin
Gas Exchange
 The final line of defense
for the respiratory system
is in the alveoli
 Macrophages wander in and out of the
alveoli picking up bacteria, carbon particles,
and other debris
 Surfactant coats the gas-exposed alveolar
surfaces
 Lowers the surface tension of the film of
water lining each alveolar sac so that the
alveoli do not collapse between each
breathe
Respiratory Membrane
(Air-Blood Barrier)