The Respiratory System
LUNG CAKE
Functions of the Respiratory
System
Obtain O2 from environment
Expel CO2 into the environment
Filter foreign particle out of incoming air
Regulates H2O content and temperature of
incoming air
Creates vocal sounds
Contributes to sense of smell
Helps regulate blood pH
Steps for Respiration
1) Breathing or ventilation

Moving air in and out of lungs
2) External respiration

Exchange of gases between lungs and blood vessels
3) Transport of gases to cells
4) Internal respiration

Exchange of gases between blood vessels and cells
5) Cellular respiration

Using O2 in metabolic processes to create energy
Divisions of Respiratory Tract
Upper respiratory tract

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Nose
Nasal cavity
Paranasal sinuses
Pharynx
Lower respiratory tract

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Larynx
Trachea
Bronchial tree
Lungs
Nose
Bone and cartilage

Support structure
Nostrils

Openings for entry of air
Nose hairs

Guard entrance and protect against particles
Nasal Cavity
Hollow space behind nose
Nasal septum

Bone and cartilage structure dividing cavity into 2 sides
Nasal conchae

Projections from nasal cavity wall; increase surface area
Lining of nasal cavity

Pseudostratified epithelial cells with mucous-secreting
goblet cells
Particles are trapped and moved out and air is
warmed and moistened
The NOSE bones and cartilage support
nose, two openings (nostrils), hair filters
large particles
Nasal Cavity –
hollow space
behind the
nose Nasal
septum – divides
the nose (bone)
Nasal conchae – bones that divide the nasal
cavity, support the mucus membrane and
increase surface area (superior, middle,
inferior)
* deviated septum – when the septum
bends to one side
Nasal Conchae
Function of the
conchae - increase
surface area
Mucus Membrane warms and moistens
air, also traps
particles (dust)
*particles go to
stomach
Paranasal Sinuses
Air-filled sacs within skull bones
Reduce the weight of the skull
Affect sound of the voice
Paranasal Sinuses
- – spaces within
the bones
maxillary
frontal
ethmoid
sphenoid
•
•
•
•
reduce the weight of
skull and are resonant
chambers for voice.
Pharynx
Shared with digestive system
Divisions:
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Nasopharynx
Oropharynx
Larygopharynx

Otherwise known as
hypopharynx
Openings:

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Oral cavity
Nasal cavity
Esophagus
Trachea
The three pharyngeal regions
Pharynx – behind the
oral cavity, between the
nasal cavity and larynx
(space, not a structure)
Larynx
Enlargement at beginning of trachea
Framework of muscle and cartilage bound
by elastic tissue
Largest cartilages:
Thyroid (Adam’s apple)
 Cricoid
 Epiglottic

Vocal Cords
Housed in larynx
False vocal cords

Fold of tissue that helps to close passageway
when swallowing
True vocal cords
Vibrate when air is forced through causing
sound
 Tension of chords helps regulate pitch
 Force of air helps regulate volume of sound

Larynx – enlargement at
the top of the trachea and
below pharynx, conducts
air in and out of trachea,
houses vocal cords
- composed of a
framework of muscles
and cartilages (thyroid
(Adam’s apple), cricoids,
epiglottic cartilages)
Glottis
Triangular opening between vocal cords
When swallowing:
False vocal cords close glottis
 Larynx raises and presses epiglottis against
opening

Glottis
- false vocal folds (do not
produce sound) – help close
airway during swallowing
- true vocal folds (produce
sound) – changing shape of the
pharynx, and oral cavity
changes sounds into
words
- contracting and relaxing
muscles changes pitch
(increased tension = higher
pitch)
www.voiceinfo.org
Steven Tyler's Vocal Cords
Glottis – triangular slit that opens during
breathing/talking, and closes during swallowing
Epiglottis – flaplike structure that stands upright, allows
air to enter larynx, during swallowing it presses
downward and prevents food from entering air passages
LARYNGITIS
When the mucus membrane becomes swollen and
prevents the vocal cords from vibrating freely.
Trachea (windpipe), flexible cylinder with cartilage to give it
stiffness and keep
it from collapsing
Trachea leads to
the BRONCHIAL TREE
Trachea
Also called windpipe
Descends anterior to esophagus
Lining of trachea:

Pseudostratified epithelial cells with mucoussecreting goblet cells
Enclosed with C-shaped rings of hyaline
cartilage to prevent tube from collapsing
Bronchial Tree
Branching tubes connecting trachea to site
of gas exchange in lungs

Right and left primary bronchi  Secondary
bronchi  Tertiary bronchi  Bronchioles 
Terminal bronchioles  Respiratory bronchioles
 Alveolar ducts  Alveolar sacs  Alveoli
Amount of cartilage decreases through tract
Amount of smooth muscle in the walls
increases through tract
Primary bronchii --> bronchioles --> alveolar ducts --> sacs
--> alveoli
*gas exchange
Alveoli
Terminal sacs at the end of the tract
Surrounded by network of blood capillaries
Site of gas exchange
Respiratory membrane:
Simple squamous epithelium in alveoli and
blood capillary
 Basement membrane fuses the two (alveoli
and capillary) together

Alveoli & Lungs
ALVEOLI
$20,000 PYRAMID!
A word/phrase will be posted – person A (who is
facing the board) must attempt to explain the word
(without saying it!) while Person B (who is NOT
facing board) will guess what the word is.
NO DRAWING!
If your partner gets them all right – with NO
CHEATING – raise your hands!
GET READY!!!!
Alveoli
Larynx
Trachae
Quick Quiz
1.
2.
3.
4.
What do you call the bones found within the nasal cavity?
What specific bone divides the nasal cavity into two sides?
The space at the back of the mouth is the________.
The spaces within the bones of the skull are called the
______________________
5. What structure is known as the windpipe? ______
6. What is the triangular slit that opens during breathing and
talking?
7. In what structures does gas exchange occur?
8. During swallowing, this flap closes to prevent food from
entering the airway: ______________________
Lungs
Located in thoracic cavity:
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Mediastinum between
Thoracic cage surrounds
Diaphragm below
Suspended by bronchi and blood vessels
Cover by visceral pleura which folds back to
become parietal pleura

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Potential space between is pleural cavity
Small layer of serous fluid between
Right lung: 3 lobes
Left lung: 2 lobes
LUNGS - spongy tissue that sit within
the pleural cavity
Right Lung
= 3 lobes
Left Lung
= 2 lobes
Serous fluid
lubricates lungs
during breathing
EXHALATION
As the diaphragm and other muscles relax,
ELASTIC RECOIL from surface tension
forces air out.
Muscles can force extra air out or in
Inspiration
At rest, pressure of air and thoracic cavity are the
same;

NO net movement of air
Pressure must be decreased in thoracic cavity for
air to move in
Diaphragm is contracted (lowered) and external
(inspiratory) intercostal muscles contract as well
Contractions increase cavity volume which
decreases pressure
Inspiration (cont)
Muscle movements pull on the pleural membranes
to expand the lung
Surface tension


Difficulty in expanding alveoli because the walls tend to
stick together
Surfactant helps
combat surface tension
Deeper breaths can be
taken by contracting muscle
more forcefully or by
involving other muscles
Expiration
Normally passive process
Contracting muscles relax
Elastic recoil and surface tension cause
tissue to return to previous state before
inspiration
Pressure increases in cavity and forces air
out of lungs
Expiration (cont)
More air can be expelled if:
Internal (expiratory) intercostal muscle
contract  Pushes rib cage in (raising thoracic
pressure even more)
 Abdominal muscles contract  raising
abdominal pressure  pushing diaphragm
higher  raising thoracic pressure even more

Respiration animation
Respiratory Air Volumes
Spirometry - measures the amount (volume) of air
moving in and out of the lungs
Respiratory Cycle - 1 inspiration and 1 expiration
ATMOSPHERIC PRESSURE = 760 Hg
Pressure is necessary for
breathing, which is why it
is difficult to breathe in
high altitudes and also
why a punctured lung
can be dangerous.
A hole in the pleural cavity
can cause the lung to
collapse or deflate
Pneumothorax = collapsed
lung: See Video
Also check out this procedure where fluid is
drained from the lungs - not for those with a weak
stomach!
Labeling Practice
1) By YOURSELF – using no notes, text –
label the respiratory system diagram
• 1 minute time – GO!
2) Switch with someone at your desk
3) Grade the diagram – you may use notes,
text
• 1 minute – GO!
4) Take a look at diagram key – make any
changes!
Image adapted from http://www.arthursclipart.org/
Resting Tidal Volume amount of air that enters
the lungs during one cycle
*take a normal breath
Reserve volumes - air that can be forced out or
in
*inhale normally, pause, and try to inhale more that is your reserve inspiratory volume
*exhale, then exhale a little more
VITAL CAPACITY = Insp reserve + Exp reserve + Tidal Volume
INSPIRATORY CAPACITY = Tidal Volume + Insp Reserve
Volume
FUNCTIONAL RESIDUAL CAPACITY is the volume of air that
remains in the lungs at rest
TOTAL LUNG CAPACITY varies by sex, age, body size,
athletics
Air Volumes
Four Respiratory Volumes

1) Tidal Volume
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2) Inspiratory reserve volume
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Amount of air that can be forcefully inhaled over tidal volume
(about 3,000ml)
3) Expiratory reserve volume
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Amount of air moved during one respiratory cycle (resting
tidal volume about 500ml)
Amount of air that can be forcefully exhaled over tidal
volume (about 1,100ml)
4) Residual volume

Amount of air left in lungs after the most forceful expiration
(about 1,200ml)
Air Capacities
Four respiratory capacities:

1) Vital Capacity
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2) Inspiratory capacity
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Amount of air that can be inspired after a resting expiration
(about 3,500ml)
3) Functional residual capacity
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Maximum amount of air that can be exhaled after deepest
breath (about 4,600ml)
Volume of air in lungs after resting expiration (about 2,300ml)
4) Total lung capacity

Total amount of air that lung can hold (about 5,800ml)
Air Volumes and Capacities
(cont)
Some volumes and capacities can change
with age, sex, body size, and health
Anatomical dead space:
Air that fills passageways to alveoli;
 No gas exchange occurs
 About 150ml

Lab- Measuring Lung Capacity
Breathing is involuntary, but
muscles are under
voluntary control
Respiratory Center –
groups of neurons in the
brain that control
inspiration and expiration
(based in the medulla
and the pons)
Factors Affecting Breathing
*Chemosensitive areas – detect
concentrations of chemicals like
carbon dioxide and hydrogen
1. Rise in CO2
2. Low blood oxygen (peripheral
chemoreceptors, carotid and aortic
bodies, sense changes)
3. Inflation reflex – regulates the
depth of breathing, prevents
overinflation of the lungs
4. Emotional upset, fear and pain
Hyperventilation - increase breathing,
lower CO2 concentration
Breathing into a bag
can restore CO2
concentrations
Control of Breathing
Respiratory center of brainstem controls both
inspiration and expiration
Medullary rhythmicity area
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Dorsal respiratory group- emit bursts that cause
muscles of inspiration to contract; impulse starts slow
and builds; no impulse during expiration
Ventral respiratory group - impulse increase
inspiratory movements and forceful expiratory
movements needed during deeper breathing
Pneumotaxic area of pons

Controls dorsal respiratory group by inhibiting
impulses; as inhibition increases breathing rate
increases
Factors Affecting Breathing
Chemosensitive area within respiratory
center
Senses changes to CO2 and H+ levels;
 Increase breathing rate and tidal volume if high

Peripheral chemoreceptors in carotid and
aortic bodies
Sense changes in O2 levels;
 Increase breathing rate if levels are extremely
low

Factors Affecting Breathing
(cont)
Inflation reflex

Stimulates pneumotaxic area to inhibit inspiration if
tissues in visceral pleura, bronchioles, or alveoli are
being overstretched
Fear and pain

Increase breathing rate
Breathing can be voluntary

Body will override if breath is held to long
Hyperventilation

Lowers levels of CO2 in blood; allows for breath to be
held longer before levels raise again; can make O2
levels low enough to cause fainting
Diffusion at the Respiratory
Membrane
Partial pressure of gases determine direction of
movement
Air in alveoli
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PCO2 = 40 mm Hg
PO2 = 104 mm Hg
Blood entering capillary
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PCO2 = 45 mm Hg
PO2 = 40 mm Hg
Blood leaving capillary - same as alveoli
Opposite exchange occurs between the
capillaries and tissue
Oxygen Transport
Over 98% of O2 attaches to heme group of
hemoglobin in red blood cells to form
oxyhemoglobin
Remaining dissolves in blood
Hemoglobin releases O2 when:
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PO2 is low
PCO2 is high
pH is acidic
Temperature is higher
Carbon Dioxide Transport
About 7% can be transported as CO2
dissolved in the blood
23% is carried by amine group of
hemoglobin to form carbaminohemoglobin

Releases when PCO2 is low
Remaining is carried as bicarbonate ion
Bicarbonate Ion
Reaction uses enzyme, carbonic
anhydrase, in RBC’s
Reaction:

CO2 + H2O  H2CO3  H+ + HCO3-
Formation of bicarbonate ion can create
excess H+ and create acidic pH;

H+ is combined with hemoglobin to minimize
this effect
Gas Exchange Animation
Respiratory Disorders
Emphysema
Emphysema
TV ad
Progressive, degenerative disease
 Destroys alveolar walls
 Results in air sacs merge to form larger
chambers (decreases surface area  reduces
volume of gases that can be exchanged)
 Person has trouble breathing
 Causes:

Exposure to respiratory irritants (tobacco smoke,
polluted air)
 Inherited enzyme deficiency

Respiratory Disorders
Lung Cancer
Like all other cancers, uncontrolled division of
abnormal cells (rob other cells of their
nutrients and gases)
 Cancer cells divide often to form tumors
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Can block airways and reduce gas exchange
Causes:

Exposure to respiratory irritants (tobacco smoke,
polluted air)
Treated with chemotherapy, surgery
 Survival rate is low 

Chronic obstructive pulmonary
disease, or COPD, is a longlasting obstruction of the
airways that occurs with
chronic bronchitis, emphysema,
or both. This obstruction of
airflow is progressive in that it
happens over time.
SMOKING IS THE MOST COMMON
CAUSE OF COPD & EMPHYSEMA
Bronchitis is inflammation of the main
air passages to the lungs. Bronchitis
may be short-lived (acute) or chronic,
meaning that it lasts a long time and
Respiratory Membrane – alveoli and blood stream
exchange gasses
Gas exchange occurs across a membrane a layer of simple squamous cells
Oxygen DIFFUSES into the bloodstream
Other substances (like alcohol can diffuse too)
Hypoxia is a disease in which there is an overall lack of oxygen
content within the body's tissue and vital human organs (specifically
the brain).
Hypoxia has several potential causes, including: cardiac arrest, severe
head trauma, carbon monoxide poisoning, suffocation, strangulation,
and choking, as well as any instance in which oxygen supply is
deprived from the body.
Asphyxia is a condition of severely deficient
supply of oxygen to the body that arises from
being unable to breathe normally.
An example of asphyxia is choking. Asphyxia
causes generalized hypoxia, which primarily
affects the tissues and organs.
ILLNESSES RELATED TO THE RESPIRATORY SYSTEM
1. Cystic Fibrosis (genetic)
2. Asthma
3. Bronchitis
4. Apnea
5. Emphysema
6. Lung Cancer
7. Altitude Sickness
8. Chronic Obstructive Pulmonary Disease (COPD)
9. Sinusitis
10. Bacterial or Viral Infections (cold, flu, pneumonia)
What is sleep apnea?
Pause or slowing of breathing during sleep
Video on Sleep Apnea
Lung Cancer
Lung cancer starts when
abnormal cells grow out of
control in the lungs. Lung
cancer and smoking often,
but not always, go hand in
hand. There usually are no
signs or early symptoms of
lung cancer. As lung cancer
stages advance, lung
cancer symptoms may
include coughing,
wheezing, shortness of
breath, and bloody mucus.
Treatment for lung cancer
can include surgery,
chemotherapy, and /or
ALTITUDE SICKNESS
Acute mountain sickness is brought on by the
combination of reduced air pressure and lower
oxygen concentration that occur at high
altitudes. Symptoms can range from mild to
life-threatening, and can affect the nervous
system, lungs, muscles, and heart.
Pulmonary edema is an abnormal build up of
fluid in the air sacs of the lungs, which leads to
shortness of breath
NON RESPIRATORY MOVEMENTS
Coughing, sneezing,
laughing, crying
Hiccup - spasm of the
diaphragm
Yawn - possibly causes by
low oxygen levels
Respiratory Fun sounds!
Cough:

Take a deep breath, closes glottis, forces air
upward from lungs against closed glottis 
glottis opens suddenly, blast of air forced
upward
Sneeze:
Like a cough
 Clears upper respiratory passages rather than
lower ones
 Initiated by mild irritation in nasal cavity

Respiratory Fun sounds!
Hiccup:
Caused by sudden inspiration due to a
spasmodic contraction of a diaphragm
 Air strikes vocal folds causing hiccup sound

Yawning:

Aid respiration by providing an occasional
deep breath