Transcript The Respiratory System

The Respiratory System
Inhale … Exhale …
How important is the Respiratory
System?
• How long can you hold your breath?
2 different levels
• Cellular, or internal
• Organism level
Why Breath?
• Respiratory System is a group of organs
working together to bring about the
exchange of oxygen and carbon dioxide
with the environment
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Respiratory System consists of:
Nose
Nasal cavity
Pharynx
Larynx
Trachea
Smaller conducting passageways
Lungs
• air is about 21% Oxygen; 78% Nitrogen;
1% Carbon dioxide, water vapor, argon,
and other trace gasses (neon, helium,
krypton, hydrogen, and ozone are a few)
• Air enters through the nose or mouth
• Into the nasal cavity – warms and
moistens air
• Enters pharynx – back of throat – serves
as passageway for food and air
• Trachea – windpipe – leads to lungs
• Direct connection to outside – must filter
dust, dirt, smoke, bacteria and other
contaminants
• When air goes through the mouth, it
doesn’t get filtered as much as when it
goes through the nose and nasal cavities
• Lined with mucous secretions and hair
• Top of trachea is
Larynx
• Made of cartilage
(largest is the Adam’s
Apple)
• Also known as Voice
box
• Inside is two folds of
tissue – the vocal
cords
Trachea
• C – shaped rings
of cartilage
• Protect the
trachea
• Make it flexible
• Keep it from
collapsing
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Cells that line the trachea
produce mucus
Lined with cilia
Particles are trapped in the mucus and carried to
upper trachea – swept down into digestive
system
• Smoke = Sabotage to system
• Cilia stop working after a while
• When this happens, particles get lodged in the
trachea – SMOKER’S COUGH
• Trachea divides to bronchi
• Bronchi divide into smaller and smaller
passageways and lose the cartilage rings
to become bronchioles
• Bronchioles divide further and further until
they end in small clusters of hollow air
sacs – alveoli
• Gas exchange occurs in alveoli
• Mechanics of Breathing
• Inhalation and Exhalation
• Air pulled into the lungs and air pushed out
of the lungs
• 10 – 15 X in a minute
• Diaphragm – large flat muscle along
bottom of rib cage and Intercostal
(between ribs) muscles
Makeup of air we breath
Gas
Oxygen
Carbon
Dioxide
Nitrogen
Chemical
Symbol
Air
Air Leaving
Entering
Lungs
Lungs
O2
19.97%
16%
CO2
0.03%
4.00%
N2
80%
80%
3 million alveoli in a healthy lung
• Blood enters capillaries around the alveoli
• Carbon dioxide rich blood enters, Carbon
dioxide diffuses out, Oxygen diffuses in –
concentrations are unequal across the
alveolar membrane of gasses
• Phospholipids and protein produce a
“surfactant” to coat the inside of the
alveolus
• Keeps it open and makes it easier to
exchange gasses
• Hemoglobin – Found in red blood cells –
iron containing compound – makes red
blood cells red
• Without Hemoglobin, blood would only be
able to carry about 2% of the oxygen
needed by the body.
• Control of Respiratory System
• Breathing is involuntary
• What makes you breath?
• How does the nervous system control
breathing?
• Sensory neurons check levels of gasses in
your blood.
• One set in carotid arteries in the neck
• Other set in the aorta
• These are sensitive to levels of gasses in
the blood – especially Carbon Dioxide
LUNG CAPACITIES
• Total Lung Volume – about 6 L
• Residual Volume – Following a normal
exhalation, what is left (about 2 ½ L)
• Tidal Volume – Volume of air inspired or expired
during a normal (at rest) breath (1/2 L per cycle)
• Inspiratory Reserve – additional air that can be
breathed after a normal inspiration (4 ½ L)
• Vital Capacity – total volume of breathable air
Problems
• Hypoxia – High CO2 levels in the blood –
provides greatest stimulus to breath
• Influenced by oxygen partial pressure, increased
gas density, and emotional states
• Asphyxia – existence of both hypoxia (oxygen
shortage) and Carbon Dioxide excess
• Suffocation – stoppage of breathing for any
cause resulting in asphyxiation
• Strangulation – stoppage of breathing due to
obstruction
Asthma
• Restriction of airways due to inflammation
• May cause
– Shortness of breath
– Wheezing
– Coughing
• Can be triggered by
– Cold
– Allergies – dust, pet hair, smoke, pollen, etc…
– Exercise
Asthma
• Medicines include
– Long acting to prevent attacks
– Short acting during attacks (bronchodilators)
Lung Caner
Emphysema
• COPD – Chronic
Obstructive Pulmonary
Disease
– Lung tissue destroyed –
cannot function fully
– Irreversible condition
– Steroids and other drugs
– May need Oxygen
permanently