respiratory system mechanics
TRANSCRIPT
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Group 10
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Remember to breathe.
It is after all, the secretof life.
Gregory Maguire,A Lion Among Men
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Introduction
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To distribute oxygen to, and remove carbon dioxidefrom all the cells of the body
To achieve this, it works together with thecirculatory system
The Primary Role of the
Respiratory System
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Respiration
The movement of air intoand out of the lungs
The transport of oxygenand carbon dioxidebetween the longs and
body cells
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Ventilation
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The proportion of pressure that the a gas exerts in amixture
In the atmosphere, at sea level, the total pressure is760 mmHg
Oxygen makes up 21% of the total atmosphere, andtherefore has a partial pressure of 160 mmHg
Partial Pressures
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Oxygen and carbon dioxide diffuse down theirpartial pressure gradients, from high partial pressure
to low partial pressures
Partial Pressures
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ACTIVITY 1
Measuring Respiratory Volumes and Calculating Capacities
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Tidal Volume
Inspiratory Reserve Volume
Expiratory Reserve Volume
Residual Volume
Respiratory Volumes
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Amount of air inspired and then expired with eachbreath under resting conditions
500 ml
Tidal Volume
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Amount of air that can be forcefully expired after anormal tidal volume inspiration
Male: 3,100 ml Female:1,900 ml
Inspiratory Reserve
Volume
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Amount of air that can be forcefully expired after anormal tidal volume expiration
Male: 1,200 ml Female: 700 ml
Expiratory Reserve
Volume
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Amount of air remaining in the lungs after forcefuland complete expiration
Male: 1,200 ml Female: 1,100 ml
Residual Volume
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Respiratory Capacities
Total Lung Capacity
Vital Capacity
Forced Vital Capacity
Forced ExpiratoryVolume
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Maximum amount of air contained in lungs after amaximum inspiratory effort
TLC = TV + IRV + ERV + RVMale: 6,000 ml
Female: 4, 200 ml
Total Lung Capacity
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Maximum amount of air that can be inspired andthen expired with maximal effort
VC = TV + IRV + ERVMale: 4, 800 ml
Female: 3, 100 ml
Vital Capacity
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Amount of air that can be expelled when the subjecttakes the deepest possible inspiration and forcefully
expires as completely and as rapidly as possible
Forced Vital Capacity
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Measures the percentage of the Vital Capacity that isexpired during 1 second of the FVC test
Normally 75-85% of the Vital Capacity
Forced Expiratory
Volume
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Radius Flow(L/min)
TV ERV IRV RV VC FEV1 TLC BreathRate
5.00 7,485 499 --- --- --- --- --- --- 15
Baseline Results
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Radius Flow(L/min
)TV ERV IRV RV VC FEV1 TLC Breath
Rate5.00 7,500 500 1,200 3,091 1,200 4,791 3,541 5,991 15
Baseline Results
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Decrease the Radius byIncrements of .50 mm
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Radius Flow
(L/min
)TV ERV IRV RV VC FEV1 TLC Breath
Rate4.50 4,920 328 787 2,028 1,613 3,143 2,303 4,756 15
Radius of 4.50 mm
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Radius of 4.00 mm Radius of 3.50 mm
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Radius Flow
(L/min)TV ERV IRV RV VC FEV1 TLC Breath
Rate3.00 975 65 156 401 2,244 621 436 2865 15
Radius of 3.00 mm
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Summary of Results
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As the radius decreases, the flow rate decreases
As the radius decreases, air resistance increases
All measured parameters also decreased as theradius decreases except for Residual Volume
Discussion
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ACTIVITY 2
Comparative Spirometry
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Spirometry
It is the most commonof the pulmonary
function tests (PFTs),measuring lungfunction, specificallythe amount (volume)and/or speed (flow) ofair that can be inhaledand exhaled.
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There is a significant loss of elastic recoil in the lungtissue
This occurs as the disease destroys the walls of thealveoli
Emphysema
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Airways resistance is increased
The lungs become overly compliant and expand
easily Easy inspiration, difficult expiration
Emphysema
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The airways collapse and pinch closed before aforced expiration is completed
Volumes and peak flow rates are significantlyreduced
Elastic recoil is NOT diminished
Acute Asthma Attack
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Many people seek to relieve symptoms with aninhaler
Usually includes a smooth muscle relaxant (B2agonist or an acetylcholine antagonist)
Relieves bronchospasms and
Induces bronchodilation
Acute Asthma Attack
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Exercise
Moderate Exercise
Increased metabolicdemand met in part bychanges in respiration
Rate of breathing and
tidal volume increase Increase in tidal volume
is greater than theincrease in breathing
Heavy Exercise
Further changes inrespiration are requiredto meet the metabolicdemands of the body
Rate of breathing andtidal volume increase tomaximum tolerablelimits
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Results
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Patient
TypeTV ERV IRV RV FVC TLC FEV1 FEV1
(%)Normal 500 1,500 3,000 1,000 5,000 6,000 4,000 80%
Normal Patient
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Patient
TypeTV ERV IRV RV FVC TLC FEV1 FEV1
(%)Emphys
ema500 750 2,000 2,750 3,250 6,000 1,625 50%
Emphysema Patient
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Patient
TypeTV ERV IRV RV FVC TLC FEV1 FEV1
(%)Asthma
Attack
Plus
Inhaler
500 1,500 2,800 1,200 4,800 6,000 3,840 80%
Asthma Patient with
Inhaler
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Patient
TypeTV ERV IRV RV FVC TLC FEV1 FEV1
(%)Modera
te
Exercise1,875 1,125 2,000 1,000 ND 6,000 ND ND
Moderate Exercise
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Patient
TypeTV ERV IRV RV FVC TLC FEV1 FEV1
(%)Heavy
Exercise3,650 750 600 1,000 ND 6,000 ND ND
Heavy Exercise
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Summary
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Graphical Summary
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Discussion
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Compared to the normal patient, the TV of thepatient with acute asthma attack is lower
The patient suffering from emphysema and acuteasthma attack plus inhaler has the same TV to that ofthe normal patient
Those who have done exercise, both moderate and
heavy, have greater TV
Tidal Volume
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ALL patients have shown a lesser ERV compared tothe normal patient
The lowest ERV were exemplified by the patientswho did heavy exercise, who had Acute AsthmaAttack, and had Emphysema
Expiratory Reserve
Volume
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ALL of the patients have shown a lesser IRVcompared to the normal patient
The lowest IRV is seen on the patient whounderwent heavy excercise
Inspiratory Reserve
Volume
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Those who did exercise had the same RV with thenormal patient
Patients with emphysema had the greatest increasein RV, followed by the patient with acute asthmaattack, then the patient with the inhaler.
Residual Volume
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Least in the patient with Emphysema, followed bythe patient with Acute asthma attack, then by the
Asthmatic patient with an inhaler
Forced Vital Capacity and
Forced Expiratory Volume
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The different breathing classification among patientshave varied values for their respiratory volumes and
capacities. This is primarily due changes in thepassageway of air (bronchoconstriction, mucousproduction, increased alveolar compliance).
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ACTIVITY 3
Effect of Surfactant and Intrapleural Presure on Respiration
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A tension produced by unequal attraction in a gas-liquid boundary
This force resists any force that tends to increase thesurface area of the gas-liquid boundary and acts todecrease the size of hollow spaces such as those inalveoli and microscopic air spaces
Surface Tension
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A detergent-like mixture of lipids and proteins thatreduces the attraction between water molecules
Through this, surface tension is decreased
Surfactant
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The pressure in thepleural cavity
Between breaths, it isless than the pressurein the alveoli
Intrapleural Pressure
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Two forces cause this negative pressure condition:
First, the tendency of the lung to recoil because of the
elastic properties and the surface tension of thealveolar fluid
Second, the tendency of the compressed chest wall torecoil and expand outward
These two forces pull the lungs away from thethoracic wall, creating a partial vacuum in thepleural cavity
Negative Pressure
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presence of air in the pleural space
This can lead to lung collapse, a condition called
atelectasis
Pneumothorax
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Results
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Radius Breath
RateSurfactant Pressure
LeftPressure
RightFlow Left Flow
RightTotal
Flow5 15 0 -4 -4 49.69 49.69 99.38
No Surfactant
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Radius Breath
RateSurfactan
tPressure
LeftPressure
RightFlow Left Flow
RightTotal
Flow5 15 2 -4 -4 69.56 69.56 139.13
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Radius Breath
RateSurfactan
tPressure
LeftPressure
RightFlow Left Flow
RightTotal
Flow5 15 4 -4 -4 89.44 89.44 178.88
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Radius Breath
RateSurfactan
tPressure
LeftPressure
RightFlow Left Flow
RightTotal
Flow5 15 0 -4 -4 49.69 49.69 99.38
Baseline
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Radius Breath
RateSurfactant Pressure
LeftPressure
RightFlow Left Flow
RightTotal
Flow5 15 0 0.00 -4 0.00 49.69 49.69
Valve Open
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Radius Breath
RateSurfactan
tPressure
LeftPressure
RightFlow Left Flow
RightTotal
Flow5 15 0 0.00 -4 0.00 49.69 49.69
Valve Closed
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Radius Breath
RateSurfactan
tPressure
LeftPressure
RightFlow Left Flow
RightTotal
Flow5 15 0 -4 -4 49.69 49.69 99.38
Lungs Reset
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Discussion
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As surfactant was applied to the lungs, the pressure onthe left and right lung was maintained
Addition of surfactant increased the flow rate on eachlong
Effect of Surfactants
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In this activity, the left lung is the affected lung
When the valve was opened, the left intrapleural
pressure equalized with the atmospheric pressure Expansion did not take place, and the flow of air at
the left lung is 0
Even when the left valve is closed, the left lung did
not reinflate
In Pneumothorax
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Thank you!