The Respiratory System
Respiratory System Functions
• Gas exchange: Oxygen enters blood
and carbon dioxide leaves
• Regulation of blood pH: Altered by
changing blood carbon dioxide levels
• Voice production: Movement of air
past vocal folds makes sound and
speech
Respiratory System Functions
• Olfaction: Smell occurs when airborne
molecules drawn into nasal cavity
• Protection: Against microorganisms by
preventing entry and removing them
• Temperature regulation: Panting in
some animals
Parts of the Nose
• Nose
– Only externally
visible part of the
respiratory system
– Job is to begin
warming, purifying,
and humidifying air
Parts of the Nose
• External Nares (nostrils)
– Where air enters the
nose
– The openings
• Nasal Cavity
– Interior of the nose
– Has thin-walled
blood vessels to
begin warming air
Parts of the Nose
• Nasal Septum
– Midline dividing
nasal cavity into
two
Parts of the Nose
• Respiratory Mucosa
– Sticky mucous
– Moistens air and
traps bacteria &
debris
– Ciliated cells move
mucous back
toward throat
Parts of the Nose
• Conchae
– Mucosa-covered
projections
– Increase surface
area & air
turbulence
– Provide more
opportunity for
warming &
filtration
Parts of the Nose
• Hard Palate
– Anterior separation
of nasal & oral cavity
– Supported by bone
• Soft Palate
– Posterior separation
of nasal & oral cavity
Cleft Palate
• Palate does not fuse
together
• Can also affect the lip
Parts of the Nose
• Paranasal Sinuses
– Openings in skull bones
– Lighten the skull
– Resonance chambers for speech
– Produce mucus
Parts of the Pharynx
• Pharynx
– Muscular passageway for food & air
– “Throat”
– About 5 inches long
– Broken into 3 parts
Parts of the Pharynx
• Internal Nares
– Opening between
nasal cavity and
pharynx
Parts of the Pharynx
• Nasopharynx
• Oropharynx
• Laryngopharynx
– Three divisions of
Pharynx
– Listed from superior to
inferior
– After passing through,
air enters larynx, food
enters esophagus
Parts of the Pharynx
• Pharyngeal Tonsils:
– AKA adenoids
– High in the nasopharynx
– Trap bacteria/pathogens
• Palatine Tonsils
– In oropharynx, end of soft palate
– When you get your tonsils out, this is what is removed
– Trap bacteria/pathogens
• Lingual Tonsils
– Base of the tongue
– Trap bacteria/pathogens
FYI: Tonsilitis
• Catch too much bacteria; palatine tonsils can’t keep
up!
EEW.
• http://video.about.com/coldflu/Tonsillitis.htm
Larynx
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•
•
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AKA Voice Box
Routes air and food into proper channels
Inferior to pharynx
Formed by 8 rigid cartilages and a spoonshaped flap of elastic cartilage (epiglottis)
– Thyroid cartilage = Adam’s apple
Epiglottis
• Cartilage flap of larynx; protector!
• When not swallowing:
– Epiglottis flapped up
– Does not block larynx
• When you are swallowing:
– Larynx rises
– Epiglottis falls
– Larynx closed off
– This means that food is directed into esophagus
• FYI: If anything other than
air tries to enter the larynx,
a cough reflex is triggered
to get it out and prevent it
from going into the lungs!
Vocal Folds
• Vocal Folds
– Formed from folds in
larynx membrane
– Vibrate with expelled
air
• Glottis
– Slit-like passageway
between vocal folds
• http://video.about.com/coldflu/Laryngitis.htm
• YouTube - Video Stroboscopy of the Vocal
Cords
• YouTube - Mythbusters - Helium and Sulfur
Hexafluoride
Trachea
• AKA windpipe
• Has cartilage rings around
it to keep it open during
pressure changes
• About 4 inches long
• Lined with ciliated mucosa
to propel mucus (with dust
particles & debris) away
from the lungs to the
throat
Primary Bronchi
• Two (right & left)
• Formed by division of
trachea
• Enters the lung, and then
breaks off into secondary
bronchi
Mediastinum
• Most central area of the thoracic cavity
• Includes heart, great blood vessels, bronchi,
esophagus, etc. (everything except lungs)
Lungs
• Site of gas exchange
• Soft & Spongy, only
weigh about 2 ½
pounds
• Each lung divided
into lobes
– Left: 2 lobes
– Right: 3 lobes
Parts of Lungs
• Apex
– Narrow superior portion
– By clavicle
• Base
– Wide inferior portion
– Rests on diaphragm
• Visceral Pleura
– Covers surface of lung
– Along with parietal pleura,
provides attachment and
eliminates friction
Bronchial Tree
• Bronchioles
– All of the branching of respiratory passageways in
the lungs
– Divisions include
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Primary bronchi
Secondary bronchi
Tertiary bronchi
Bronchioli
Terminal bronchioli
(end in alveoli)
This image is
showing the
carina – the
point where
the primary
bronchi break
off from each
other.
Alveoli
• “Air Sacs”
• Resemble bunches of grapes
• Make up bulk of lungs
Respiratory Zone
• Includes respiratory bronchioles, alveolar
ducts, alveolar sacs, and alveoli
• Only places where gas exchange occurs
Walls of Alveoli
• Made of single, thin
layer of simple
squamous epithelial
cells
• Covered with a
cobweb of
pulmonary
capillaries
Respiratory Membrane
• Made up of alveolar and
capillary walls
• Has air flowing on one side,
blood flowing on the other
• Gas exchange occurs
through simple diffusion
– Oxygen from alveolar air
to capillary blood
– Carbon dioxide leaving
blood to air
FUN FACT: total surface of alveoli
walls is about 50-70 square meters
- about the surface of a tennis
court!
• http://highered.mcgrawhill.com/sites/0072495855/student_view0/ch
apter25/animation__gas_exchange_during_re
spiration.html
• http://video.about.com/asthma/How-LungsFunction.htm
Steps to Respiration
• 1. Pulmonary Ventilation (breathing)
– Air move in and out of lungs so alveoli air is
refreshed
• 2. External Respiration
– Gas exchange between blood and alveoli air
• 3. Respiratory Gas Transport
– Gas transport between lungs and body by
bloodstream
• 4. Internal Respiration (Cellular Respiration!)
– In body, at capillaries, gas exchange between
blood and tissue cells
Respiration
• Inspiration
– Air flowing into lungs (breathe in!)
• Expiration
– Air leaving the lungs (breathe out.)
• Volume changes lead to pressure changes,
which lead to the flow of gases to equalize the
pressure!
Inspiration
• Diaphragm and external intercostals contract
– Diaphragm actually moves DOWN when contracts
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Thoracic cavity size increases
Rib cage lifts
Intrapulmonary volume increases
Gas molecules spread out due to increased
volume! This causes a decrease in pressure,
which pulls in more gas.
Inspiration
Expiration
• Diaphragm and external intercostals relax
– Internal intercostals and abdominal muscles
contract if expiration is forced
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Thoracic cavity size decrease
Rib cage descends
Intrapulmonary volume decreases
Gas molecules get closer together due to the
decrease in volume! This causes an increase
in pressure, which forces gas out.
Expiration
Non-Respiratory Air Movements
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Cough
Sneeze
Crying – release of air in short breaths
Laughing – release of air in short breaths
Hiccups
Yawn
Lung Development
• Fetus
– All respiratory exchange made by placenta
– Lungs filled with fluid
• Birth
– Fluid drained, passageways fill with air
– Surfacant: fatty molecule that lines each alveolar
sac to prevent from collapsing (don’t have enough
of this until fetus is 30 weeks)
– Lungs do not fully inflate for 2 weeks after birth
– 20 to 40 respirations/min
Lung Development
• Teens
– 12 to 18 respirations/min (rates differ depending on
source)
– Continue to develop alveoli (smoking stops this
production!)
• Elderly
– Chest wall becomes rigid, lungs lose elasticity, cilia in
trachea less effective
– Vital capacity decreases
– More at-risk for respiratory tract conditions
– 18 to 20 respirations/min
Respiratory Conditions
• Pulmonology – study of diseases of the lungs
and respiratory tract
• Hypoxia – inadequate oxygen delivery to body
tissues, causes cyanosis (bluish-tone of skin)
Upper Respiratory Tract Infection
• Includes things like the
common cold, sinusitis,
tonsillitis, and laryngitis
• Symptoms include nasal
congestion, cough,
running nose, sore
throat, fever, facial
pressure, and sneezing
• http://video.about.com/coldflu/UpperRespiratory-Infection.htm
• http://video.about.com/coldflu/Sinusitis.htm
Lung Cancer
• 1/3 of all cancer deaths in the US
• Very low survival rate, because usually not
caught until very advanced
• Growth usually occurs in the bronchial tree
• Problem with smoking…
– Kills off cilia that cleans & moves mucus out of
airway
– Mucus collects
– Traps carcinogens from cigarettes
COPD
• Chronic Obstructive Pulmonary Disease
– Characterized by limited airflow
– Symptoms include coughing, wheezing, and
shortness of breath (dyspnea)
– Usually have a history of smoking, but can
also be caused by other inhalants (coal,
asbestos, air pollution)
COPD
– Patients retain carbon dioxide, meaning
blood becomes slightly acidic
– Usually results in respiratory failure
– Two major types (there are other types, but
these are the most common)…
Emphysema
• Characterized by
breakdown of elastin in
connective tissue of
lungs
• Leads to destruction of
alveolar walls
• Lungs become less
elastic, which makes it
difficult to exhale
Chronic Bronchitis
• Characterized by inflammation of the bronchi
• Mucosa lining of lower respiratory passages
become inflamed and produces excess mucus,
which leads to blockage
• Symptoms include persistent coughing with
sputum, cyanosis very common
Acute Bronchitis
• Caused by virus or
bacteria
• Only last
days/weeks
• Symptoms same as
chronic bronchitis
• http://video.about.com/asthma/Bronchitis.ht
m
Pneumonia
• Characterized by:
Inflammatory illness of the
lungs, alveoli become filled
with fluid
• Varied causes, including
bacteria, virus, fungi,
chemical, & physical
• Often diagnosed with chest xray
Asthma
• Characterized by airways constricting due to
trigger (exposure to allergens, pollutants, cold
air, warm air, moist air, exercise, or emotional
stress)
• Symptoms include wheezing, shortness of
breath, chest tightness, and coughing
• Scientists believe cause is combination of
genetics and environment
• Inhalers act as bronchodilator
Sleep Apnea
• Characterized by pauses of
breathing during sleep
• 5 or more events, lasting at
least 10 seconds each
• Caused by blockage of the
airways due to causes such
as decreased muscle tone,
increased soft tissue
around airway (obesity),
and structural features
(deviated septum, enlarged
tonsils)
Carbon Monoxide Poisoning
• Competes with oxygen for same binding sites
on hemoglobin
• Binds VERY easily, and so it pushes out oxygen
• Leading cause of death from fire
• Victim usually becomes confused, has
headache, and blushing of skin
Cystic Fibrosis
•
Cystic Fibrosis is a recessive
genetic disease that effects
both the digestive and
respiratory system.
•
Abnormally thick mucus
gets stuck in many places.
Most commonly in the
lungs & pancreatic duct
•
Symptoms can include
persistent coughing,
shortness of breath and
frequent upper respiratory
infections.
1 in 20 people are
unaffected carriers!
Cystic Fibrosis
• Easily diagnosable with
a sweat test
• Treatment for the GI
tract involves taking
digestive enzymes
before eating.
• Treatment for the lungs
is called CPT, Chest
Physiotherapy.
– A light clapping of the
chest, back, and under
the arms to loosen
mucus in the lungs