Transcript The Human Respiratory System

The Human
Respiratory
System
HUMAN RESPIRATORY
STRUCTURES
• Nose/mouth: filters,
moistens, warms
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Pharynx
Larynx
Trachea – mucus, cilia
2 lungs
– 2 bronchi
– Bronchioles
– Alveoli
• Site of exchange
• Thin walls, lots-ocapillaries
• Large #  S.A.
• A thin layer of
mucus is produced
on the lining of the
tubes of the
respiratory system
This thin layer traps
particles of dust or
smoke
 These tubes are lined
with CILIA that sweep
away particles
• These tubes are
made of cartilage
and are surrounded
by smooth muscle
CILIA
ALVEOLI
• Small structures at the end of each
bronchiole
• Occur in clusters
• Place where gas exchange occurs
– Oxygen into blood, carbon dioxide into lung
– Each is surrounded by capillaries
• 300 million alveoli are in each healthy lung
– Provides a large surface area for gas exchange
• Oxygen dissolves in the moisture
– It can then diffuse into the capillaries
– CO2 diffuses in the opposite direction
– Coated in surfactant
HEMOGLOBIN binds with so much oxygen
that it increases the oxygen carryingcapacity of the blood more than 60 times
RECAP
• Name the structures of the respiratory
system
• Where does gas exchange occur?
• http://www.airinfonow.org/html/lungattack/l
ungplay.htm
• Next: What is the difference between
respiration and breathing?
Breathing
• Breathing is the movement of
air into and out of the lungs
• Lungs sit in two sacs = pleural
membranes
• At the bottom of the chest cavity
is the diaphragm
• Between ribs are intercostal
muscles
Force that drives breathing is air
pressure
– No muscles are directly
connected to the lungs
Volume
If you have a container of gas,
how will the pressure change if you make
the container smaller?
Make it larger?
• When you inhale,
the diaphragm
contracts and
expands the
volume of the
chest cavity
• Because the chest
cavity is tightly
sealed, this
creates a partial
vacuum inside the
cavity
• Air rushes into the
lungs as a result
Inhaling
Exhaling
• Exhaling is a passive event
• Diaphragm relaxes and lungs return to
normal size, placing pressure on the lungs
– Air rushes out of the lungs
78% Nitrogen
21% Oxygen
0.03% Carbon
Dioxide
Partial Pressure: “Concentration of
Gas”
1) Volume: If you have a container of gas, how
will the pressure change if you make the
container smaller? Make it larger?
– Bulk Flow ~ Breathing
2) Total atmospheric pressure = 760mmHg
– Oxygen is 21% of this, therefore = 159mmHg
• O2 air > O2 alveoli > O2 blood > O2 cells
• 159mmHg 100mmHg
40mmHg 40mmHg
(exchange to 100mmHg)
– Diffusion
RECAP
• What causes breathing?
• What muscles are involved with
breathing?
– Are they attached to the lungs?
• What controls your breathing?
Breathing Control
• Breathing is voluntary to a point, then it
becomes involuntary
• Nervous system will take over
– Sensory receptors in major blood vessels
detect amount of carbon dioxide in blood
• b/c pH will change
– Message goes to medulla oblongata in the
brain
– If the level of carbon dioxide gets too high, the
diaphragm will contract
Hb + 4O2  “HbO”
Oxygen in Blood
• 98.5% is bound to Hb
• 1.5% dissolved in plasma
Carbon Dioxide in Blood
• 60% dissolves in H2O (as
H2CO3)
• 30% binds to Hb
• 10% dissolves in plasma
Carbon Monoxide
• Hb affinity 200 X’s stronger
• irreversible
REGULATION of pH
• Normal plasma pH = 7.4 (Range: 7.35 7.45)
CO2 + H20
H2CO3
H+
+
HCO3Waste product
of metabolism
Always
Present
Converted to
Waste product
Buffer
Products on
of metabolism
LEFT by
Carbonic Anhydrase
____________________________________________________________________________________________________
Expelled by
Adjusted in kidney
Lung
Or Rxts w/Bicarb. R.
Or Rxts w/H+ on L.
The exchange
• http://www.airinfonow.org/html/lungattack/lungplay
.htm
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What can go wrong?
http://www.hisdbenefits.org/hisd/living/animations/
List of animations for respiratory disorders
http://in.truveo.com/Human-AtlasEmphysema/id/1459776665
• Similar animations, better quality
Breathing Quiz:
Is it inhalation or exhalation?
• Diaphragm
Contracts
• Intercostal
Muscles relax
• Chest Cavity
increases in size
• Pressure in cavity
decreases
• Air rushes out of
lungs
• Diaphragm relaxes
• Intercostal
muscles contract
• Volume of chest
cavity decreased
• Pressure inside
greater
• Air rushes in and
inflates lungs