1. Identify and give the functions for each of the following:
Larynx,Trachea, Bronchi, Bronchioles, Alveoli, Diaphragm &
ribs, Pleural membranes, and Thoracic cavity.
2. Compare and contrast the mechanics of the processes of inhalation
and exhalation .
3. Explain the relationship between the structure and function of the
alveoli.
4. Explain the roles of the cilia and mucous in the respiratory tract.
5. Describe the interaction of the lungs, pleural membranes, ribs, and
diaphragm in the breathing process.
6. Explain the roles of carbon dioxide and hydrogen ions in stimulating
the breathing centre in the medulla oblongata.
7. Describe the exchange of carbon dioxide and oxygen during internal
and external respiration.
8. Distinguish between the transport of carbon dioxide and oxygen in
the blood by explaining the roles of oxyhemoglobin,
carboxyhemoglobin, reduced hemoglobin, and bicarbonate ions.
_____ Alveoli
_____ Bicarbonate ions
_____ Breathing
_____ Bronchi
_____ Bronchioles
_____ Carbaminohemoglobin(HbCO2)
_____ Carbon dioxide
_____ Carbonic anhydrase
_____ Carboxyhemoglobin (HbCO2)
_____ Cartilage
_____ Cellular respiration
_____ Chemoreceptors
_____ Cilia
_____ Diaphragm
_____ Epiglottis
_____ Esophagus
_____ Exhalation/Expiration
_____ External respiration
_____ Hemoglobin
_____ Hydrogen ions
_____ Inspiration/Inhalation
_____ Intercostal muscles
_____ Internal respiration
_____ Larynx
_____ Lipoproteins (surfactant)
_____ Medulla oblongata
_____ Mucous
_____ Nasal sinus
_____ Nose hairs
_____ Oxyhemoglobin (HbO2)
_____ Pharynx
_____ Pleural membrane
_____ Pneumothorax
_____ Pulmonary capillaries
_____ Reduced hemoglobin (HHb)
_____ Sinus
_____ Stretch receptors
_____ Surface tension
_____ Thoracic cavity
_____ Trachea
_____ Vocal cords
The right lung is slightly larger than
the left.
Hairs in the nose help to clean the air
we breathe, as well as warming it.
The highest recorded "sneeze speed"
is 165 km per hour.
The surface area of the lungs is
roughly the same size as a tennis
court.
Each red blood cell has about 200250 million Hemoglobin molecules.
The capillaries in the lungs would extend 1,600 km if
placed end to end.
We lose half a litre of water a day through breathing. This
is the water vapour we see when we breathe onto glass.
A person at rest usually breathes between 12 and 15
times a minute.
The breathing rate is faster in children and women than in
men.
Lung breathing probably evolved about 400 million years
ago.
Part of Respiratory system
http://video.about.com/
lungdiseases/HowLungs-Function.htm
The Nasal Sinus is surrounded by a lot of capillary beds
and mucous glands. Because it is one of the major entry
ways into the body it has many things to help keep us safe
1. Nose hairs: with the aid of mucous, these hairs filter
and trap debris. The debris that is trapped in this
manner is discharged through the nose.
2. There are many white blood cells here to recognize and
destroy foreign objects.
3. Histamines are released here as an allergic response
when foreign irritants are encountered. This causes
runny nose.
This is the common passageway for air and food
This is a flap of tissue that covers the top of the trachea
when swallowing to ensure that food enters the esophagus
and not the lungs.
When the epiglottis is
opened, the air is able to
pass through the larynx
(voice box) and into the
trachea.
The larynx contains the
vocal cords (two tendons
that adjust the pitch of sounds
according to how taut they
are).
When a guy goes through
puberty, his vocal chords
and voice box (larynx)
grow larger, and begins
to stick out at the front of
the throat. This lump is
called the Adam's Apple.
Male vocal cords: 17 mm & 25 mm in
length.
Female vocal cords: 12.5 mm & 17.5 mm
[1
in length.
This is the windpipe.
This passageway is
held open by the
presence of C-shaped
rings of cartilage.
This is a protective
adaptation.
The trachea conducts
air into the bronchi.
•Cilia and mucus filter the
air as it moves through the
trachea.
•The mucous traps the dirt
and other particles, and the
cilia push it to the back of
the throat so we swallow it
into our digestive system
Cilia with pollen trapped by mucous.
The trachea splits into
two bronchi and takes
the air into each lung.
These branches also
have cartilage around
them, for the same
reason.
The bronchi conducts
air into smaller
branching passageways
called bronchioles.
The bronchioles are
branching passageways
that carry air to its
ultimate destination, the
alveoli.
Several things happen to the air on its way to the alveoli. It is:
1. Adjusted to Body Temperature: By the time it arrives at
the alveoli the air has been in contact with many tissues
and is 37o C.
2. Adjusted to 100% humidity. As inhaled air passes over
the mucous passageways, it becomes saturated with water.
3. Cleansed of debris in a 2 part process.
1. Nose hairs and mucous in the nasal passageways.
2. Mucous and Cilia in Trachea and bronchi. *Note: cilia
do not filter!
These are the blind sac-like
endings at the end of the
bronchioles.
There are approx. 700,000
alveoli in the human lung.
This is the site of gas exchange.
O2 leaves the alveoli and moves
into the blood to be taken around
the body.
CO2 does the opposite and is
breathed out.
Why are they so special?
1. NUMEROUS: Each adult lung
contains millions of alveoli. This
provides lots of surface area for
the gases to be exchanged.
2. THIN WALLS: The walls of
alveoli are only one cell thick.
3. STRETCH RECEPTORS:
They have stretch receptors that
signal when the alveoli are full
enough (stretched). They send a
message to the brain to start
exhalation.
Why are they so special?
4. MOIST: They are very moist
and this helps gas exchange.
5. VERY RICH BLOOD SUPPLY:
They have a close association
with many blood capillaries so
oxygen and carbon dioxide
can be exchanged efficiently.
6. LINED WITH A LAYER OF
LIPOPROTEINS (surfactant)
on their inner surface. This
helps to maintain surface
tension, thus preventing them
from collapsing and sticking
together during exhalation.
This is a sheet of
muscle that
separates the chest
cavity from the
abdominal cavity.
When you inhale it
moves down.
When you exhale it
moves up.
These are the bones that are connected to the vertebral
column and sternum.
These are INTERCOSTAL muscles between the ribs, which
help to move the ribs…
1.Up and out when we inhale.
2.Down and in when we exhale.
Our control of the breathing
process is only voluntary to a
point.
The medulla oblongata of the
brain is sensitive to the
concentration of carbon dioxide
and hydrogen ions in the blood.
When the concentrations of H+ and CO2 reach a critical level,
the breathing center in the medulla oblongata is stimulated
and sends nerve impulses to the diaphragm and the
intercostal muscles.
When the brain realizes there is
too much CO2 in our blood, it
sends a message to the rib
muscles and diaphragm to
contract.
The ribs move up and out, the
diaphragm moves down.
This creates more space in the
lungs (negative air pressure)
and air rushes in to fill that
space.
This is called inhalation.
When the alveoli get too
stretched (full of air), they send
a message to the brain to stop
inhaling.
The brain tells the muscles to
relax and the ribs move back
down and in, while the
diaphragm moves back up.
This decreases the amount of
space in the lungs and the air is
pushed out.
This is called exhalation.
See a Working
Respiratory
System:
http://www.smm.org/heart/
lungs/breathing.htm
These are membranes that enclose the lungs.
The outer pleural membrane sticks closely to the walls of the
chest & the diaphragm.
The inner pleural membrane is stuck to the lungs. The two lie very
close to each other.
The pleura allows
the surface of the
lungs to slide
over the body
wall easily,
without abrasion.
The pleura seals off the thoracic
cavity so when the lungs inflate, a
negative air pressure is created
and this causes air to rush in.
These membranes also stick the
lungs to the chest cavity walls, so
when the ribs move out, so do
the lungs.
A puncture to the chest wall, piercing the
pleural membrane (even without damaging
the lung itself), will result in a
pneumothorax, or collapse of the lung.
In a situation like this, the negative
pressure effectively draws air in through
the puncture wound, putting pressure on
the surface of the lung instead of inside it
and the lung collapses.
Respiration is the set of processes involved with the
conduction of oxygen to the tissues and the removal of the
waste product CO2.
There are four aspects to respiration:
1. Breathing: the inspiration and expiration of air.
2. External Respiration: gas exchange at the alveoli.
3. Internal Respiration: gas exchange at the tissues.
4. Cellular Respiration: mitochondria turn O2 and glucose
into CO2 and H2O and ATP energy.
Happens at the lungs.
It is the diffusion of O2 into the
pulmonary capillaries (blood) and the
diffusion of CO2 and water into the
alveoli to be exhaled with the air.
Because there is a lot of CO2 returning to the lungs, and not very
much in the alveoli, the CO2 diffuses from [H] to [L] down its
concentration gradient and moves into the alveoli to be breathed
out.
Because there is a lot of O2 in the fresh air in the alveoli, and not
much in the deO2 blood, the oxygen diffuses from [H] to [L]
down its concentration gradient and into the blood.
Conditions in the blood at the alveoli are:
Basic: pH of ~7.4
Cool: ~37o C
Low (negative) pressure
Under these conditions, hemoglobin lets go of CO2 and starts
to love oxygen.
As it leaves the lungs, 99% of hemoglobin is
occupied with oxygen it is called oxyhemoglobin.
O2 + Hb
HbO2
Hemoglobin transports oxygen to the tissue cells.
Happens at the tissues.
It is the diffusion of O2 into
the tissue cells, and the
diffusion of CO2 and water
into the blood capillaries.
The CO2 is then returned to
the heart and sent to the
lungs to be removed during
exhalation.
O2
CO2
Conditions in the blood at the tissues are:
Acidic: pH of ~7.3
Warm: ~38o C
High pressure
Under these conditions, hemoglobin lets go of O2 and starts
to love CO2 and H+. HbO
Hb + O
2
2
The oxygen diffuses into the tissue spaces along with the
water that is forced from the plasma due to blood pressure.
CO2 + H2O +
O2 + GLUCOSE
At the venule end of the capillary bed, when water is drawn back
into the blood by osmotic pressure, CO2 enters the blood.
Carbon dioxide can be transported in three ways:
1. Dissolved gas, 2. Carboxyhemoglobin (HbCO2), 3. Bicarbonate ion (HCO3-)
Because the hemoglobin now
loves the CO2, they join to form
carboxyhemoglobin.
CO2 + Hb
HbCO2
CO2 also joins with water to
make the bicarbonate ion.
There is an enzyme in the red
blood cells called CARBONIC
ANHYDRASE which catalyzes
this reaction.
CO2 + H2O
HCO3-
H2CO3
Carbonic anhydrase
Carbonic anhydrase
+
H+
CO2 + H2O
Carbonic anhydrase
The extra hydrogen ion from
the water is now free. This is
BAD as it is ACIDIC and can
eat through the blood vessel
walls.
So, hemoglobin acts as a
buffer and joins with the
hydrogen ion to make
reduced hemoglobin.
H+ + Hb
HCO3-
H2CO3
HHb
Carbonic anhydrase
+
H+
When the blood returns to the
lungs, the conditions change
again, and hemoglobin
dumps CO2 and H+ & wants
to pick up O2 again.
So all of the reactions happen
in reverse.
HbCO2
HHb
H+
CO2 + Hb
H+ + Hb
+ HCO3-
H2CO3
Carbonic anhydrase
CO2 + H2O
Carbonic anhydrase
At this point, all that is left to be excreted at the lungs is water and
CO2.
So the CO2 diffuses into the alveoli and is exhaled.
The water will either:
1. Be exhaled in the air
2. Enter the alveoli to keep them moist
3. Remain in the plasma
H2O + CO2
Gas Exchange
• Partial Pressure
– Each gas in atmosphere contributes to the entire
atmospheric pressure, denoted as P
• Gases in liquid
– Gas enters liquid and dissolves in proportion to its
partial pressure
• O2 and CO2 Exchange by DIFFUSION
– PO2 is 105 mmHg in alveoli and 40 in alveolar
capillaries
– PCO2 is 45 in alveolar capillaries and 40 in alveoli
Partial Pressures
• Oxygen is 21% of atmosphere
• 760 mmHg x .21 = 160 mmHg PO2
• This mixes with “old” air already in alveolus to
arrive at PO2 of 105 mmHg
• Carbon dioxide is .04% of atmosphere
• 760 mmHg x .0004 = .3 mm Hg PCO2
• This mixes with high CO2 levels from residual
volume in the alveoli to arrive at PCO2 of 40
mmHg
Gas Exchange Between the Blood and Alveoli
Gas Exchange Between the Blood and Alveoli
Volume (ml)
Measurement of Lung Capacity
Measurement of Lung Capacity
Lung volumes and vital capacity

Total Lung Volume: (~6000ml)

Measurement: Spirometer



Tidal Volume (~500 ml): Volume of air inhaled
and exhaled in a single breath
Inspiratory Reserve Volume (~3100 ml): The
amount of air that can be inhaled beyond the
tidal volume
Expiratory reserve volume (~1200 ml): the
amount of air that can be forcibly exhaled
beyond the tidal volume
Measurement of Lung Capacity



Vital Capacity (~4800 ml): The maximal volume
that can be exhaled after maximal inhalation
Vital Capacity = Tidal volume+IRV+ERV
Residual volume (~1200 ml): the amount of air
remaining in the lungs, even after a forceful
maximal expiration
Dead Space Volume: The air that remains in
the airways and does not participate in gas
exchange
•Smoking causes lung cancer and
emphysema
•Emphysema causes the alveoli to
lose their elasticity
•People who have respiratory
disease often have heart disease
•There are over 4000 chemicals in
cigarettes
•Smoking also destroys the cilia
lining in your respiratory system
so that dirt and particles can’t be
removed