A. Air volumes exchanged during breathing and
rate of ventilation are
measured with a _________________________ (respirometer), and the
record is called a spirogram
(spirograph) .
B. Pulmonary
air volumes – gas volumes exchanged in ventilation.
1. Tidal
volume (TV) – amount of inhaled or exhaled with each
breath under resting conditions.
a. Tidal volume = ________ ml in an average adult
2. Inspiratory reserve
volume (IRV) – amount of air that can be
forcefully inhaled after a normal tidal volume
inhalation.
a. Inspiratory
reserve = ________ ml in an average adult
3. Expiratory
reserve volume (ERV) – amount of air that can be
forcefully exhaled after a normal tidal volume
exhalation.
a. Expiratory reserve volume = ________
ml in an average
adult
4. Residual
volume (RV) – amount of air remaining in the lungs
after
forced exhalation.
a. The lungs are never totally empty of air. This helps keep
the alveoli patent (open).
b. Residual volume = ________ ml in an average adult
5. Only about 350 ml of the tidal volume
actually reaches the
alveoli.
a. The other 150 ml
remains in the airways - ____________
_____________________________________.
C. Respiartory
capacities - the sum of two or more volumes.
1.
Total lung capacity (TLC) –
the maximum amount of air
contained in the lungs after a maximum inspiratory
effort.
a. Total lung
capacity = ________ ml in an average adult
b. TLC = TV + IRV +
ERV + RV
2.
Vital capacity (VC) – the
maximum amount of air that can be
expired
after a maximum inspiratory effort
a. Remember that the
RV (1,200 ml) can’t be expired
1) should be 80% of TLC
b. Vital capacity =
________ ml in an average adult
c. VC = TV + IRV +
ERV
3.
Inspiratory capacity (IC) -
the maximum amount of air that can
be inspired
after a normal expiration.
a. Inspiratory
capacity = ________ ml in an average adult
b. IC = TV + IRV
4.
Functional residual capacity
(FRC) – the volume of air
remaining in the lungs after a normal tidal volume expiration.
a. Functional
residual capacity = ________ ml in an average
adult
b. FRC = ERV + RV
D. Minute
volume - the total volume of air taken in during one minute
1.
Minute volume = Tidal Volume x respirations per minute
2.
In an average adult,
a. minute volume = 500 ml x 12 = ________ ml/min.
A. Exchange of oxygen and carbon dioxide between
the blood and
alveoli, is partially explained by two gas
laws.
1.
_________________________ – each gas in a mixture of gases
exerts its own pressure, as if all the other
gases were not present.
a. Partial pressure
of a gas - the pressure exerted by that
gas in a mixture of gases.
1) Gases will flow from high to low pressures.
|
|
Inspired
air |
Blood
entering alveolar capillaries |
Blood
exiting alveolar capillaries & then entering tissue capillaries |
Tissues |
Blood
leaving tissue capillaries & then entering alveolar capillaries |
Expired air |
|
|
|
|
|
|
|
|
|
Pressure O2 |
160 mm Hg |
40 mm Hg |
104 mm Hg |
40 mm Hg |
40 mm Hg |
120 mm Hg |
|
Movement of
O2 |
O2
moves into the blood |
O2
leaves the blood |
O2
moves into the blood |
|||
|
|
|
|
|
|
|
|
|
Pressure of
CO2 |
0.3 mm Hg |
45 mm Hg |
40 mm Hg |
45 mm Hg |
45 mm Hg |
27 mm Hg |
|
Movement of
CO2 |
CO2
leaves the blood |
CO2
moves into the blood |
CO2
leaves the blood |
|||
b. Total
pressure of a mixture
– the sum of all the partial
pressures of the gases of that mixture.
1) It is symbolized by P.
2. _________________________ – the quantity
of a gas that will
dissolve in a liquid is proportional to the
partial pressure of the gas
and its solubility coefficient (its
physical or chemical attraction for
water), when the temperature remains
constant.
a. Remember that
plasma is mostly water.
b. Oxygen has a LOW
solubility in water.
1) Most of the oxygen that our cells require is
actually
carried by hemoglobin.
2) Hyperbaric oxygenation uses pressure to cause
more oxygen to dissolve in the blood.
a) Used to treat anaerobic bacterial infections
(e.g. tetanus and gangrene)
b) Used to treat carbon monoxide poisoning
c. Carbon dioxide and
nitrogen have higher solubilities in
water.
1) This explains how nitrogen narcosis and
decompression sickness (the bends) occur.
1.
O2 and CO2 diffuse from areas of their higher
partial pressures
to areas of their lower partial
pressures.
a. This results in
the conversion of deoxygenated blood
(more CO2 than O2) coming from the body
tissues to
oxygenated blood (more O2 than CO2)
leaving to the heart.
2. It depends on…
a. Partial pressure differences
b. A
large surface area for gas exchange (in the alveoli)
c. A
small diffusion distance across the alveolar-capillary
(respiratory)
membrane
d. The solubility and molecular weight of the gases.
1.
Results in the conversion of oxygenated blood into
deoxygenated blood.
2.
At rest only about _________ of the available
oxygen in
oxygenated blood actually enters tissue cells.
a. During exercise, more oxygen is released.
A. Oxygen
Transport
1.
In each 100 ml of oxygenated blood…
a. __________
of the O2 is dissolved in the plasma
b. __________
is carried with hemoglobin (Hb) inside red
blood cells as oxyhemglobin
(HbO2).
2.
The heme portion of Hb
contains 4 atoms of iron, each capable
of combining with a molecule of oxygen.
B.
Hemoglobin and Oxygen Partial
Pressure
1.
PO2 is
the most important factor that determines how much
oxygen combines with hemoglobin.
2.
Review the relationship oxygen-hemoglobin
dissociation
curve in the textbook.
a. This curve illustrates the relationship between the percent
saturation of hemoglobin and PO2.
b. The greater the PO2, the more oxygen will combine
with
hemoglobin.
c. This is true until the available hemoglobin molecules are
saturated.
C.
Other Factors Affecting
Hemoglobin Affinity for Oxygen
1.
The ________________________________ - in an acid (low
pH) environment, O2 splits
more readily from hemoglobin.
a. Low blood pH
(acidic conditions) results from high PCO2.
b. Cells produce more
CO2 during periods of increased
activity.
c. CO2 + H2O
(in plasma) ↔ H2CO3 (carbonic acid)
d. Thus, more active
cells will get more O2
2.
Within limits, as _________________________
increases, so
does the amount of oxygen released from
hemoglobin.
a. Active cells (such
as contracting muscle cells) liberate
more acid and heat.
b. This, in turn,
stimulates the oxyhemoglobin to release its
oxygen.
3.
BPG (2, 3-biphosphoglycerate) is a substance formed in red
blood cells during glycolysis.
a. The greater the level of BPG, the more oxygen is
released from hemoglobin.
5.
_________________________ has a higher affinity for oxygen
because it binds BPG less strongly and can
carry more oxygen to
offset thelow
oxygen saturation in maternal blood in the placenta.
6.
Because of the strong attraction of ______________________
_________________________ (CO) to
hemoglobin, even small
concentrations of CO will reduce the oxygen carrying
capacity
leading to hypoxia and carbon monoxide
poisoning.
D.
Carbon Dioxide Transport
1.
CO2 is carried in blood…
a. _________
in the form of dissolved CO2
b. _________
bound to Hb as carbaminohemoglobin
(carried by RBC)
c. _________
as bicarbonate ions (70%).
2.
The conversion of CO2 to bicarbonate ions and the related
chloride shift maintains the ionic balance
between plasma and red
blood cells.
3.
CO2 + H2O ↔ H2CO3 (carbonic
acid) ↔ H+ + HCO3- (bicarbonate
ion)
E. Summary
of Gas Exchange and Transport in Lungs and Tissues
1.
CO2 in blood causes O2 to split from hemoglobin.
2.
Similarly, the binding of O2 to hemoglobin causes a release
of
CO2 from blood.
1.
The area of the brain from which nerve impulses are sent to
respiratory muscles is located bilaterally in the
reticular formation of
the brain stem.
2.
This respiratory center consists of a medullary
rhythmicity area
(inspiratory
and expiratory areas), pneumotaxic area, and apneustic
area.
a. The function of the
____________________________
______________________ area is to control the basic
rhythm of respiration.
1) The _________________________________ has
an intrinsic excitability of autorhythmic neurons that
sets the basic rhythm of respiration.
2) The _________________________________
neurons remain inactive during most quiet respiration.
It aids
forced (labored) expiration.
b. The _________________________ area in the upper
pons helps coordinate the transition between
inspiration and
expiration.
c. The _________________________ area sends impulses
to
the inspiratory area that activate it and prolong
inspiration,
inhibiting
expiration.
1.
Cortical Influences - allow
conscious control of respiration.
a.
Breath holding is limited by the overriding stimuli of
increased [H+] (this leads to a drop
in pH from CO2 build up)
and [CO2].
2. Chemical
Regulation
a. ______________________________
monitor levels of
CO2 and O2 and
provide input to the respiratory center.
1)
They respond to concentration changes of H+,
PCO2, and PO2 in blood.
b. _________________________ - a slight increase in PCO2
(and thus [H+],
a decrease in pH of the blood stimulates the
chemoreceptors.
1) The inspiratory
area is activated and
hyperventilation
(rapid and deep breathing) occurs.
c. _________________________ – less than 40 mm Hg
PCO2 in
arterial blood.
1)
The chemoreceptors are not stimulated and the
inspiratory area sets its own pace until CO2
accumulates and PCO2 rises to 40 mm
Hg.
d. Severe deficiency of O2 depresses activity of the
central
chemoreceptors and respiratory center.
3. _________________________ – an oxygen
deficiency at the
tissue
level. Hypoxia is classified in several
ways.
a. _________________________ hypoxia – a low PO2 in
arterial blood
1)
This can result from high altitude, airway
obstruction, fluid in lungs, carbon monoxide
poisoning, etc.
b. _________________________ hypoxia – too little
functioning hemoglobin in the blood
1) Resulting from hemorrhage, anemia, etc.
c. _________________________ hypoxia – inability of
blood to carry oxygen to tissues fast
enough to sustain their
needs
1)
Resulting from heart failure, circulatory shock, etc.
d. _________________________ hypoxia – the blood
delivers adequate oxygen to the tissues, but
the tissues are
unable to use it properly.
1)
This can result from cyanide poisoning
4.
_____________________________ of joints and muscles
activate the inspiratory
center to increase ventilation prior to
exercise induced oxygen need.
5. The
_______________________________________________
detects lung expansion with stretch receptors
and limits it
depending on ventilatory
need and prevention of damage.
6.
Other influences include…
a. Blood pressure
b. The limbic system (emotional center of the brain)
c. Temperature
d. Pain
e. Stretching of the anal sphincter
f. Irritation to the respiratory mucosa.
A. The respiratory system works with the
cardiovascular system to make
appropriate adjustments for different exercise
intensities and durations.
1.
Ventilatory modifications can increase _______
times above
resting
levels
2. Initially, the rapid rate is due to neural
influences
3.
Then, more gradually, it is due to chemical stimulation from
changes in cell metabolism.
B. A similar, but reversed, effect occurs with
cessation of exercise.
A.
Smokers have difficulty breathing for a number of reasons, including
nicotine, mucous, irritants, and the fact that
scar tissue replaces elastic
B. _________________________ – a chronic
disorder characterized by
shortness
of breath, wheezing, coughing and tightness of the chest, often
due to
allergens. An attack can also be
triggered by emotional upset,
aspirin, exercise, and breathing cold air or cigarette
smoke.
Asthma is characterized by the
following…
1) spasms of smooth
muscle in bronchial tubes that result in partial
or
complete closure of air passageways
2) inflammation
3) inflated alveoli
4) excess mucus
production
C.
__________________________________________________
(COPD) – a type of
respiratory disorder characterized by chronic and
recurrent obstruction of air flow, which
increases airway resistance.
1)
The principal types of COPD are emphysema and chronic
bronchitis.
D. In
__________________________________________________
(lung
cancer), bronchial
epithelial cells are replaced by cancer cells after
constant irritation has disrupted the
normal growth, division, and function
of the epithelial cells.
1)
Airways are often blocked and metastasis is very common.
E. _________________________ (TB) is an inflammation of pleurae and
lungs produced
by the organism Mycobacterium
tuberculosis.
1)
It is communicable and destroys
lung tissue, leaving
nonfunctional fibrous tissue behind.
F. _________________________ (common cold) is caused by viruses
and usually
is not accompanied by a fever.
G. __________________________________________________
– an
abnormal
accumulation of interstitial fluid in the interstitial spaces and
alveoli of
the lungs.
1)
It may be pulmonary or cardiac in origin.
H. __________________________________________________
– an
inherited
disease of secretory epithelia that affects the
respiratory
passageways,
pancreas, salivary glands, and sweat glands.
allow air to enter the intrapleural
space either from the outside or from the
alveoli cause pneumothorax,
filling the pleural cavity with air.