Download 1) What are 3 functions of the respiratory system?

The Respiratory System
Class Starter Questions:
1)
2)
3)
What are 3 functions of the respiratory system?
Explain the difference between breathing and
cellular respiration.
What organs make up the respiratory system? Write
them in order through which air passes during
inhalation.
1) What are 3 functions of the respiratory
system?
 To provide oxygen to body cells so that they may
extract the energy they need from nutrients. (cellular
respiration)
 To remove carbon dioxide (waste product) from the
body.
 To filter, warm and humidify the air we breathe.
2) Explain the difference between breathing
and respiration.
Breathing is:
The process which moves air in and out of the
lungs
Cellular Respiration is:
A chemical reaction that occurs inside the
mitochondria of all cells. It is a combustion
reaction, therefore it always releases energy.
Chemical equation for cellular respiration:
C6H12O6 + 6 O2  6 CO2+ 6 H2O + energy
3) Pathway of air through the respiratory
system.
Lungs
Nose & mouth
Nasal pasage
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Alveoli
Capillaries (where O enters the blood)
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Mouth & Nose
 This is where the oxygen first
enters your body and also where carbon dioxide
leaves.
 When the air comes into your nose it gets
filtered by tiny hairs (not cilia)
 Your mouth does not contain these hairs therefore
breathing by your mouth does not filter the air as well
as breathing by your nose
Nasal cavity
 Warms & humidifies air
 Glands that produce sticky mucus line the nasal
cavity
 traps dust, pollen, and other materials that were
not trapped by nasal hairs
Pharynx
 Tube-like passageway used by food, liquid, and
air.
 At the lower end of the pharynx is a flap of tissue
called the epiglottis.
 covers the trachea during swallowing so that food
does not enter the lungs
Larynx
 “Voice box”
 The airway to which two pairs of horizontal folds
of tissue, called vocal cords, are attached
 When we exhale, the vocal cords vibrate which
produces sound
Trachea
 This is an air-conducting tube that connects the
larynx with the bronchi
 Lined with mucus membranes and cilia
 Contains strong cartilage rings to hold the airway
open at all times
Bronchi
 Two short tubes that branch off the lower end of
the trachea
 Carry air into the lungs.
 Singular - bronchus
Lungs
 The lungs are spongy organs which contain the
bronchioles and alveoli.
 Where gas exchange occurs
 There are 2 lungs (right and left)
Smoker’s Lung vs. Healthy Lung
Bronchioles
 Tiny branches of air tubes in the lungs
 Connect bronchi to alveoli
Alveoli
 Tiny, thin-walled, grapelike clusters at the end of
each bronchiole
 Surrounded by capillaries
 Where exchange of carbon dioxide and oxygen
(via diffusion) takes place
 Singular - alveolus
Pleura
 A double membrane that lines the lungs and
adheres to the walls of the rib cage
Diaphragm
• Dome shaped muscle between the chest and
the abdomen that the body uses for
breathing
Gas Exchange- What is it?
 Two gases, O2 and CO2 switch places
 O2 moves from the alveoli to the capillaries
 CO2 moves in the opposite direction, from the
capillaries to the alveoli
 This occurs by diffusion:
 The movement of molecules from a region of high
concentration to a region of low concentration
Diffusion of Carbon Dioxide
 Blood arriving at the
alveolus is
deoxygenated:
 Low in O2
 High in CO2
 The concentration of
CO2 inside the alveolus
is lower than in the
capillary
 Thus, CO2 diffuses
into the alveolus
Diffusion of Oxygen
 Blood arriving at the
alveolus has a low
concentration of O2
 But air entering the
alveolus has a high
concentration of O2
 Thus, O2 diffuses from
the alveolus (high
conc.) into the
capillary (low conc.)
Oxygenated blood
leaving the alveolus
How does breathing work?
 Breathing is an
involuntary action
meaning that it occurs
without conscious
thought
 However, breathing is
in fact controlled by a
structure in the brain
called the medulla
Breathing Rate
 Breathing rate = # of breaths (including inhalation
AND exhalation) in 1 min
 Your brain controls your breathing rate by monitoring
the level of CO2 in your body
 When CO2 levels are high, breathing rate increases
 When CO2 levels are low breathing rate decreases
Why does your breathing rate increase
during and after exercise?
 Physical activity requires increased energy
production
 Thus, your muscles must consume more O2 to
release more energy
 As a result of respiration, more CO2 is produced
 The increased levels of CO2 in the blood flowing
to your brain is a signal to the medulla to increase
breathing rate
 WHY?
 To remove CO2 and replenish O2 at a faster rate