The
Respiratory
System
(Review) Cellular Respiration
• Process by which energy from food molecules like
glucose is transferred to ATP which is a usable
form of energy to be used for cellular processes
– Takes place in the Mitochondria
– Also called “Internal Respiration”
– Aerobic: when oxygen is present
– Anaerobic: when oxygen supplies are low
• Produces fewer ATP (2 instead of 36)
• Produces lactic acid as a by product
Human Respiratory System
• Function:
– to exchange gases
between the blood and the
external environment
– Also called “External
Respiration”
– Take in oxygen
– Get rid of carbon dioxide
– Excess water also removed
• A system of passageways connects lungs to
outside air and permits air to enter the lungs and
wastes to leave
Pathway that air follows:
• Nose and Nasal Cavity
• Pharynx
• Larynx
• Trachea
• Bronchi
• Bronchioles
• Alveoli
Respiration Animation:
http://www.neok12.com/php/watch.php?v=zX7a51
620305036844477802&t=Respiratory-System
Gases in the Bloodstream
• Blood leaving lungs, high in oxygen
• Blood entering lungs, high in carbon dioxide
• Oxygen carried mainly by hemoglobin in RBCs
• Carbon dioxide is dissolved in the blood plasma
• Nose and Nasal Passages
– Air enters and is warmed by
blood flowing through
capillaries near skin
– Air is moistened and filtered
by:
• hairs lining nostrils
• Cilia lining surfaces
• Mucous secretions that trap
dust, pollen etc…
• The mucous and what it traps
eventually dry out and form
“boogers”
http://www.youtube.com/watch?v=1Fz5HiL0cgA&safe=active
Sense of Smell
• Pharynx: (throat)
– Passageway for the air
as it travels on towards
trachea
– Food also passes
through here
• Larynx:
– Contains the vocal
cords, whose vibrations
make speech possible
– Clip showing woman’s vocal cords
vibrating at high/low pitch:
http://www.youtube.com/watch?v=Up
OXecWC5Dw&safe=active
• Trachea:
– Connects the pharynx with
the bronchi
– Tube is rigidly supported by
cartilaginous ridges
– When swallowing, the
epiglottis covers the trachea
preventing food from
entering the “windpipe”
Cleaning the Air We Breathe
• Trachea and bronchiole
tubes are lined with a
ciliated membrane.
– Mucous secretions trap
particles
– Cilia sweep foreign
particles back up into the
pharynx where they are
swallowed or coughed up
http://www.youtube.com/watch?v=
miEEluVlemQ&safe=active
– Why do we Cough?
– http://www.neok12.com/php/watch.php?v=zX0
66c555347077350076077&t=RespiratorySystem
• Bronchi:
– 2 branches off trachea
that enter the lungs
• Bronchioles:
– smaller and smaller
tubes that eventually
end in alveoli
Alveoli
– The functional units
for respiration in
lungs
– Thin walled sacs
• one cell thick
– Surrounded by
capillary network
– MicroAnatomy of the Lungs: Alveoli
– http://www.neok12.com/php/watch.php?v=zX0
45c7b745d0a6d435f5245&t=RespiratorySystem
Alveoli and Gas Exchange
• Each alveolar sac is coated on
the inside with a liquid called
surfactant
• This liquid surface is
necessary for gas exchange
to take place
• Gas is exchanged by diffusion
– Area of higher concentration to
lower concentration
– Type of passive transport
– No energy required
Oxygen diffuses from
alveoli into surrounding
capillaries
Carbon dioxide and some
water diffuses from
capillaries into alveoli
– The Respiratory System: How it Works (3:30)
– http://www.neok12.com/php/watch.php?v=zX5
a5b076c436a5b690d0373&t=RespiratorySystem
• Make a Lung/Diaphragm Model
• http://www.youtube.com/watch?v=vRv2zY
H5p9k&safe=active
Mechanism of Breathing
Controlled by your
nervous system and by
muscles of the
diaphragm and ribcage
• Lungs have no muscle tissue and cannot
move by themselves
• They contract and expand due to pressure
changes causes by the movement of the
diaphragm and ribcage
• Normal breathing rate = 12-25 per minute
Inhale:
– Rib cage rises as rib muscles contract
– Diaphragm muscle lowers as it contracts
– Space in your chest cavity increases and creates a lower
air pressure space (vacuum) that causes gas from
outside to rush in to lungs
Exhale:
– Ribcage lowers
– Diaphragm goes up
as it relaxes
– Chest volume
decreases
– Increased pressure
on air inside lungs
forces most of it out
of alveoli
Breathing Animation:
http://www.biotopics.co.uk/humans/inhexh.html
• Control of Breathing
– You can control it to
some extent
– Mostly it is an
involuntary process
– Controlled by respiratory
center in the brain
• in medulla oblongata
• How does your body know to speed up breathing
rate during exercise?
• Chemoreceptors:
– sensory tissue lining aorta and other large arteries
sense amount of dissolved carbon dioxide in blood.
– Send message to respiratory center in brain
– Too much CO2 = breath deeper and more frequently
• In addition the presence of lactic acid from
heavy exercise can also stimulate the
respiratory centers of the brain
Diseases of the
Respiratory System
• Asthma:
– severe allergic reaction causes wheezing, coughing
– bronchioles squeeze air passages closed during
attack
• Pneumonia:
– alveoli become
filled with fluid
preventing gas
exchange
– caused by
bacterial infection
• Tuberculosis:
– Lung infection caused by bacteria.
– Highly contagious
– Chest pain, prolonged cough (may cough up
blood)
– May cause extensive scarring in the upper
lobes of the lungs.
• Cystic Fibrosis:
genetic disorder
(recessive)
– Abnormally thick,
sticky mucus in lungs
– Difficult for cilia to
remove mucus
– Frequent chest
infections, coughing,
shortness of breath
Lung Injury
• Collapsed Lung: due to puncture of lung
cavity
• Asbestosis:
– Asbestos fibers get trapped
in lungs
– Fibers irritate lung tissue
creating scarring and
initiating a chronic
inflammatory response
– No cure
Smoking and the
Respiratory System
• Chemicals in tobacco smoke damage structures
throughout the respiratory tract.
– Nicotine:
• addictive stimulant that increases heart rate and blood pressure
and can increase risk of heart attack
– Carbon Monoxide:
• poisonous gas that blocks hemoglobin from binding with oxygen
– Tar:
• contains at least 60 compounds known to cause cancer.
• Ex: arsenic, formaldehyde
• Smoke paralyzes cilia
– One cigarette stops their motion for about 20
minutes
• Mucus laden with particles has trouble
leaving the airways resulting in “smokers
cough”
Diseases Caused by Smoking
• Chronic Bronchitis:
– bronchial tubes become irritated and swollen
– Passageways swell and clog with mucus
– Heavy coughing and difficulty breathing
• Emphysema:
– Fragile walls of alveoli become damaged,
scarred and broken
• Less surface area for gas exchange
– Lungs become less elastic
– Get shortness of breath
– Damage to lungs cannot be fixed
• Lung Cancer:
– Tumors crowd out
functional surfaces for
gas exchange and
steal blood supply
– By the time it is
detected, it has
usually spread to body
– Usually caused by
smoking
Adaptations for Gas Exchange in
Animals
• Need moist thin walled respiratory surface
– for O2 and CO2 exchange
• More surface area = more gas exchange
Protists and Small Multicellular
Organisms
• Amoeba,
Paramecium,
Hydra:
– Most cells are in
direct contact with
environment
– Diffusion of gases
occurs across cell
membrane directly
• Aquatic Animals
– Most often exchange gases
through gills
– Thin layers of tissue richly
supplied with blood vessels
– Provide large surface area for
gas exchange
– There is much less dissolved
oxygen in water than in air
• Air = 20%, water <1%
– Must constantly move large
amount of water over
respiratory surface by
pumping or swimming
Earthworm
• Thin outer skin is the respiratory surface
– Below skin are capillaries carrying blood with hemoglobin
• Live in moist soil and constantly secretes mucus to
keep skin moist
– If exposed to air and dries out it will suffocate
Grasshopper
• System of tracheal tubes for
gas exchange
– Branching air tubes carry air
directly to cells
– Muscle contractions pump air in
and out of tubes
• Spiracles: outside openings
that lead to tracheal tubes
• Review Website:
• http://kidshealth.org/teen/your_body/body_basics/lungs.html
• Review of Respiration:
• http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP15104
• Review Website with Practice Problems
• http://www.biotopics.co.uk/humans/resyst.html
• Interactive Anatomy Website:
• http://www.anatronica.com/anatronica-flash-respiratory-system.html
• Interactive Practice:
– Label the parts of the Respiratory System
– http://www.neok12.com/diagram/Respiratory-System-01.htm
• Respiratory System: (25 minutes Coronet Film)
• http://www.youtube.com/watch?v=yWnlhcqJlRk&
list=PL2FC882112DF30CFB&index=24&safe=ac
tive
• Bill Nye: The Respiratory System (25 minutes)
• http://www.youtube.com/watch?v=q3Do0eeRRe
U&list=PLORF26ONn8gSytdZkl1TlWZxsDwJG6vN&safe=active