Chapter 13
 Nose
 Pharynx
 Larynx
 Trachea
 Bronchi
 Lungs—alveoli
Figure 13.1
 Gas
exchanges between the blood and
external environment
• Occurs in the alveoli of the lungs
 Passageways
to the lungs conduct,
purify, humidify, and warm the incoming
air
 Only
externally visible part of the
respiratory system
 Air enters the nose through the external
nostrils (nares)
 Interior of the nose consists of a nasal
cavity divided by a nasal septum
Figure 13.2
 Olfactory
receptors are located in the
mucosa on the superior surface
 The rest of the cavity is lined with
respiratory mucosa that
• Moisten air
• Trap incoming foreign particles
 In
cold weather, cilia become “sluggish”
and mucus tends to accumulate
 Lateral
walls have projections called
conchae
• Increase surface area
• Increase air turbulence within the nasal cavity
– deflects foreign particles  mucus-coated
surfaces so they can’t enter lungs
 The
nasal cavity is separated from the
oral cavity by the palate
• Anterior hard palate (bone)
• Posterior soft palate (muscle)
 Bones
of hard palate do not fuse properly
 difficulty in
• breathing
• chewing
• speaking
 Causes, incidence, and risk factors
• genetics, drugs, viruses, or other toxins can all cause
such birth defects
• may occur along with other syndromes or birth
defects
• risk factors include a family history of cleft lip or
palate and other birth defect; ~ 1/ 2,500 people
 Symptoms
• ≥ 1of these conditions @birth
• small notch in the lip
• complete split in the lip that goes all the way to the
base of the nose
• one or both sides of the roof of the mouth
• may go the full length of the palate
 Cavities
within bones surrounding the
nasal cavity are called sinuses
 Sinuses are located in the following
bones
• Frontal bone
• Sphenoid bone
• Ethmoid bone
• Maxillary bone
 Lighten
skull
 Act as resonance chambers for speech
 Produce mucus
• drains  nasal cavity
• suctioning effect from nose blowing will drain
sinuses
 Nasolacrimal
also
ducts drain  nasal cavity
Sinuses are not fully
developed until after age
twelve. When people speak
of sinus infections, they are
most frequently referring to
the maxillary and frontal
sinuses.
Figure 13.2
When the sinus openings become blocked or too
much mucus builds up, bacteria and other germs can
grow more easily.
 Sinusitis can occur from one of these conditions:

• cilia in the sinuses - help move mucus out - do not work
properly
• colds and allergies: too much mucus , blockage of sinus
openings
• deviated nasal septum, nasal bone spur, or nasal polyps may
block the opening of the sinuses.

Sinusitis can be:
• acute -- symptoms last up to 4 weeks; caused by bacterial
infection in sinuses that results from URI
• sub-acute -- symptoms last 4 - 12 weeks
• chronic -- symptoms last 3 months or longer; long-term
swelling/inflammation of the sinuses; caused by
bacteria/fungus
 Muscular
passage from nasal cavity to
larynx (~13 cm.)
 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
 Pharyngotympanic
tubes open into the
nasopharynx
 Tonsils of the pharynx
• Pharyngeal tonsil (adenoids) are located in the
nasopharynx
• Palatine tonsils are located in the oropharynx
• Lingual tonsils are found at the base of the
tongue
Figure 13.2
 Causes,
incidence, and risk factors
• strep throat
• tonsils may become so overwhelmed by
bacterial/viral infection that they swell and
become inflamed
• infection may also be present in throat and areas
around it, causing inflammation of pharynx
tube runs from middle ear 
back of throat
 Eustachian
• drains fluid that is normally made in the middle ear
• when blocked, fluid can build up
• bacteria/viruses multiply  infection (acute otitis
media)
 Chronic
ear infection may be caused by an
acute ear infection that does not clear
completely, or repeated ear infections
• fluid in middle ear may become very thick
• sometimes, tympanic membrane may stick to bones
in middle ear
 Inferior
to pharynx
 Routes air and food into proper channels
 Plays a role in speech
 Made of eight rigid hyaline cartilages
and a spoon-shaped flap of elastic
cartilage (epiglottis)
 Thyroid cartilage
• largest of the hyaline cartilages
• protrudes anteriorly (Adam’s apple)
 Epiglottis
• protects superior opening of larynx
• routes food to esophagus, air toward trachea
• when swallowing, epiglottis rises and forms lid
over the opening of the larynx
• cough reflex is activated when anything other
than air enters trachea; doesn’t work when
unconscious
 Vocal
folds (true vocal cords)
• Vibrate with expelled air to create sound
(speech)
 Glottis—opening
between vocal cords
 In
the past, thought to be caused by
psychological problem
 Now - problem in brain/nervous system
• vocal cord muscles spasm, causing the vocal
cords to get too close or too far apart while
people with the condition are using their voice
 Usually
occurs ages 30 – 51
 Women more likely to be affected than
men
Figure 13.2
 4” tube
- connects larynx w/bronchi
 Reinforced w/C-shaped hyaline
cartilage
 Lined w/ciliated mucosa
• Beat continuously in opposite direction of
incoming air
• Expel mucus loaded w/dust & other debris
away from lungs
 Open
part @ back allows expansion of
esophagus
 Solid part @front supports trachea walls
patent (open) despite pressure changes
associated w/breathing
 If
repeated attempts do not free airway,
emergency cut in windpipe
(tracheostomy or cricothyrotomy) may
be necessary
 Huge amounts of mucus form due to
tracheal irritation – must be suctioned
Figure 13.3a
Figure 13.3b
 Inhibits
ciliary action; ultimately destroys
cilia
 Coughing is only method of preventing
mucus from accumulating in lungs
 Smokers should avoid cough
suppressants
 Formed
by division of the trachea
 Enters the lung at the hilum (medial
depression)
 Right bronchus is wider, shorter, and
straighter than left (more common site for
object to become lodged)
 Bronchi subdivide into smaller and
smaller branches
 * Air entering bronchi is warm, clean
damp
Figure 13.1
Figure 13.4b
 Occupy
most of the thoracic cavity
• Heart occupies central portion called
mediastinum
 Apex
is near the clavicle (superior
portion)
 Base rests on the diaphragm (inferior
portion)
 Each lung is divided into lobes by
fissures
• Left lung—two lobes
• Right lung—three lobes
Figure 13.4a
Figure 13.4b
 Serosa
covers outer surface of lungs
• Pulmonary (visceral) pleura covers lung surface
• Parietal pleura lines walls of thoracic cavity
 Pleural
fluid fills area between layers of
pleura to allow gliding
 These two pleural layers resist being
pulled apart
Figure 13.4a
 Symptoms
• chest pain that most likely occurs when coughing or
taking a deep breath in or out
• some feel pain in shoulder
• deep breathing, coughing, chest movements makes
pain worse
 Pleurisy
can cause fluid to collect inside
chest cavity
•
•
•
•
cyanosis
coughing
shortness of breath
tachypnea (rapid breathing)
 Signs
and tests
• normally smooth pleura become rough
• rub together with each breath
• may produce a rough, grating sound called a
"friction rub"
• health care professional can hear this with
stethoscope or by placing an ear against chest
 All
but the smallest of these passageways
have reinforcing cartilage in their walls
• Primary bronchi
• Secondary bronchi
• Tertiary bronchi
• Bronchioles
• Terminal bronchioles
conducting zone
structures
Figure 13.5a
 Structures
• Respiratory bronchioles
• Alveolar ducts
• Alveolar sacs
respiratory
zone
• Alveoli (air sacs)
 Site
of gas exchange = alveoli only
Figure 13.5a
 Respiratory
membrane = alveolar walls +
capillary walls + their fused basement
membranes + occasional elastic
membranes
 Thin
squamous epithelial layer lines
alveolar walls
 Alveolar pores connect neighboring air
sacs
• Provide alternative air pathway if there’s mucus
blockage, etc
 Pulmonary
capillaries cover external
surfaces of alveoli
 On one side of the membrane is air and
on the other side is blood flowing past
Figure 13.6 (1 of 2)
Figure 13.6 (2 of 2)
 Gas
crosses the respiratory membrane
by diffusion
• Oxygen enters the blood
• Carbon dioxide enters the alveoli
 Alveolar
macrophages (“dust cells”) add
protection by picking up bacteria,
carbon particles, and other debris
 Surfactant (a lipid molecule) coats gasexposed alveolar surfaces (more later)
 Pulmonary
ventilation—moving air in and
out of the lungs (commonly called
breathing)
 External respiration—gas exchange
between pulmonary blood and alveoli
• Oxygen is loaded into the blood
• Carbon dioxide is unloaded from the blood
Figure 13.6 (2 of 2)
 Respiratory
gas transport—transport of
oxygen and carbon dioxide via the
bloodstream
 Internal respiration—gas exchange
between blood and tissue cells in
systemic capillaries
 Completely
mechanical process that
depends on volume changes in the
thoracic cavity
 Volume changes lead to pressure
changes, which lead to the flow of gases
to equalize pressure
 Two
phases
• Inspiration = inhalation
 flow of air into lungs
• Expiration = exhalation
 air leaving lungs
 Diaphragm
and external intercostal
muscles contract
 The size of the thoracic cavity increases
 External air is pulled into the lungs due
to
• Increase in intrapulmonary volume
• Decrease in gas pressure
Figure 13.7a
Figure 13.8
 Largely
a passive process which depends
on natural lung elasticity
 As muscles relax, air is pushed out of the
lungs due to
• Decrease in intrapulmonary volume
• Increase in gas pressure
 Forced
expiration can occur mostly by
contracting internal intercostal muscles
to depress the rib cage
Figure 13.7b
Figure 13.8
 Normal
pressure within the pleural space
is always negative (intrapleural pressure)
 Differences in lung and pleural space
pressures keep lungs from collapsing
 Can
be caused by reflexes or voluntary
actions
 Examples:
• Cough and sneeze—clears lungs of debris
• Crying—emotionally induced mechanism
• Laughing—similar to crying
• Hiccup—sudden inspirations
• Yawn—very deep inspiration
Table 13.1
 Normal
breathing moves about 500 mL of
air with each breath
• This respiratory volume is tidal volume (TV)
 Many
factors that affect respiratory
capacity
• A person’s size
• Sex
• Age
• Physical condition
 Inspiratory
reserve volume (IRV)
• Amount of air that can be taken in forcibly over
the tidal volume
• Usually between 2100 and 3200 mL
 Expiratory
reserve volume (ERV)
• Amount of air that can be forcibly exhaled
• Approximately 1200 mL
 Residual
volume
• Air remaining in lung after expiration
• About 1200 ml
 Vital
capacity
• The total amount of exchangeable air
• Vital capacity = TV + IRV + ERV
• Dead space volume
 Air that remains in conducting zone and never
reaches alveoli
 About 150 mL
 Functional
volume
• Air that actually reaches the respiratory zone
• Usually about 350 mL
 Respiratory
capacities are measured with
a spirometer
Figure 13.9