Internal
& External Respiration
Events #2 & 4
 Used to
determine the
individual
pressures of
each gas in a
mixture of
gases
 Based on % of
total of 760
mmHg of total
atmospheric
pressure
 Gas exchanges that occur:
Between the blood and the alveoli AND
Between the blood and the tissue cells
Take place by simple diffusion
Depends on partial pressures of oxygen & carbon
dioxide that exist on opposite sides of the
exchange membrane (Dalton’s law of partial
pressures)
 Always flowing from high to low

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

 states
that the solubility of a gas in a liquid is
directly proportional to the pressure of that
gas above the surface of the solution (IOW:
the higher the pressure of the gas, the more
gas will be shoved into the liquid thus
increasing solubility)
 Solubility (of a gas) and partial pressure have
a direct relationship
 The
solubility coefficient of the gas also
affects this process – the higher the #, the
more the gas “likes” to dissolve into a liquid
(based on molecular structure, etc.)
 Each gas will dissolve in a liquid in
proportion to the ratio between its partial
pressure gradient and its solubility
coefficient
 CO2 = .57
 O2 = .024
 N2 = .012
 Solubility
& temperature have an inverse
relationship.
 Increase in temperature causes increase in
kinetic energy causes more molecular motion
which allows molecules to break the
intermolecular bonds and escape from
solution
 And vice versa

Partial pressure gradients
and gas solubilities
 Oxygen = has low
solubility but steep
partial pressure gradient
(105 mmHg in alveoli –
40 mmHg in blood = 65
mmHg pressure
gradient)
 Carbon dioxide = has
solubility ~20x greater
than oxygen but partial
pressure gradient is only
5 mmHg
 Partial pressure gradients and gas
solubilities
 Due to the ratios of solubility coefficients and
pressure gradients:
 ~Equal amounts of gases are exchanged
 Thickness of respiratory membranes
 0.5 to 1.0 micrometers
 edematous (swollen) tissue can be caused by
congestion and pneumonia - hinders diffusion
leading to hypoxia oxygen deprivation
 Surface Area
 50-70 square
meters for gas
exchange
 Emphysema or
cancer
 Walls of alveoli
break down
 Less surface area
for gas exchange
 The phrenic &
intercostal nerves
transmit impulses to
the respiratory
muscles
 Irritation to phrenic
nerve is responsible
for hiccups (spasm
of diaphragm
muscle)
 Neural centers are
located in medulla &
pons
 Eupnea = normal respiration rate
 Approx 12-15 breaths per min
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Hyperpnea = higher than normal rate
Apnea = No rate
Dyspnea = general term for abnormal rate
Physical factors, conscious control, emotional
factors, and chemical factors all influence rate
& depth of breathing.
 Deep & rapid respiration, too much CO2 is
vented out of the body so:
 Not enough acid production
 H2O + CO2 = H2CO3 (carbonic acid)
 Respiratory alkalosis results
 Treatment: trap the CO2 and
rebreathe it till breathing returns
to normal
 Slow & shallow respiration with not adequate
expiration so CO2 is not vented out of the body
 Production of excess acid
 H2O + CO2 = H2CO3 (carbonic acid)
 Respiratory acidosis results
 Usually caused by disease process:
 COPD
 Asthma
 Obesity
 Trauma
 Pneumonia
 Symptoms: inflammation of mucosa –
chronic mucus production
 Normal
 Bronchitis
 Breathing is very labored due to
lack of alveolar recoil
 End stage: Alveolar walls collapse
= loss of surface area so less gas
diffusion
 Membranes thicken so decrease in
diffusion eventually
 Both emphysema and chronic bronchitis have:
 Smoking history
 Dyspnea = air hunger due to dysfunctional
breathing
 Coughing & pulmonary infections
 Will develop respiratory failure, hypoxia, acidosis
 Basic Info
 1/3 of all cancer deaths are due to lung cancers
 90% have a smoking history
 Metastasizes VERY rapidly due to vascularity of
lungs


Begins in
larger bronchi
& bronchioles
Forms masses
that have
bleeding
cavities within
them


Nodules that
develop in
peripheral areas
of lung
Develop from
alveolar cells &
bronchial
glands



Originate in primary
bronchi
Grow into small grape
like clusters in
mediastinum
Very aggressive cancer
 Resection of diseased portion of lung
(thoracotomy)
 Radiation therapy
 Chemotherapy
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Genetic disorder – recessive
Causes oversecretion of thick mucus that
clogs respiratory passages
Impairs food digestion by clogging ducts that
secrete enzymes
Multiple other organs are affected
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Sudden, unexplained death of an infant less
than 1 year old
Possibly caused by brain abnormalities that
control respiration, heart rate, or
consciousness
Environmental factors to reduce risks – sleep
on back not on stomach, firm crib with no
blankets or stuffed animals or pillows
Sudden infant death syndrome (SIDS): Risk
factors - MayoClinic.com
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Chronically inflamed hypersensitive bronchial
passageways
Bronchoconstriction of passageways in
response to allergen, temperature changes, &
exercise
Can be managed with medication
 Hyperbaric
oxygen
chambers –
designed to
force greater
amounts of
oxygen into
patient’s blood
 Treats tissues
affected by poor
circulation

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Patient breathes in regular air while body is
under pressure
Increased pressure means increased
solubility of gases (incl oxygen)
More oxygen in blood benefits treatment of
certain conditions
Tetanus
 Gangrene
 Migraines
 Slow healing
wounds
 Burns/skin grafts
 Stroke
 Autism
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Traumatic Brain
Injury
Decompression
Sickness
Cerebral Palsy
Multiple Sclerosis
Fibromyalgia
Many other
conditions

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The Physics of Diving - Scuba Gas Laws
As you go down in depth, the water puts
pressure on your body
Increased pressure = increased solubility of
inhaled gases into the blood
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•
As you come up at the correct rate, the
pressure decreases slowly
So the solubility decreases slowly
So the gases come out of the blood
And you can exhale them
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•
If you come up too rapidly, the pressure
decreases rapidly
So the solubility decreases rapidly
So the gases come out of the blood too fast
to exhale them properly
The excess gas bubbles can collect in joint
spaces, arteries, tissues, etc. causing
coronary, pulmonary, or brain embolisms

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
Auditory or eustachian tubes provide an
avenue for equalizing middle ear pressure
with atmospheric pressure via the flow of
gases
Air will either move in or out of your ears to
cause this equalization
This is the cause of your ears “popping”

Notice swollen vocal cords and mucus
accumulation
Read
through the Developmental
Aspects section of your notes