Transcript Expiratory Reserve Volume

Respiratory System
23-1
Respiration
• Ventilation: Movement of air into and out
of lungs
• External respiration: Gas exchange
between air in lungs and blood
• Transport of oxygen and carbon dioxide in
the blood
• Internal respiration: Gas exchange between
the blood and tissues
23-2
Respiratory System Functions
• Gas exchange: Oxygen enters blood and carbon
dioxide leaves
• Regulation of blood pH: Altered by changing
blood carbon dioxide levels
• Voice production: Movement of air past vocal
folds makes sound and speech
• Olfaction: Smell occurs when airborne
molecules drawn into nasal cavity
• Protection: Against microorganisms by
preventing entry and removing them
23-3
Respiratory System Divisions
• Upper tract
– Nose, pharynx
and associated
structures
• Lower tract
– Larynx,
trachea,
bronchi, lungs
23-4
• Nose
Nose and Pharynx
– External nose
• Pharynx
– Nasal cavity
– Common opening
• Functions
for digestive and
respiratory systems
–Passageway for air
– Three regions
–Cleans the air
–Humidifies, warms air • Nasopharynx
• Oropharynx
–Smell
–Along with paranasal • Laryngopharynx
sinuses are resonating
chambers for speech
23-5
Larynx
• Functions
– Maintain an open passageway for air
movement
– Epiglottis and vestibular folds prevent
swallowed material from moving into
larynx
– Vocal folds are primary source of sound
production
23-6
Vocal Folds
23-7
Trachea
Insert Fig 23.5 all but b
• Windpipe
• Divides to
form
–Primary
bronchi
23-8
Tracheobronchial Tree
• Conducting zone
– Trachea to terminal bronchioles which is
ciliated for removal of debris
– Passageway for air movement
– Cartilage holds tube system open and
smooth muscle controls tube diameter
• Respiratory zone
– Respiratory bronchioles to alveoli
– Site for gas exchange
23-9
Tracheobronchial Tree
23-10
Bronchioles and Alveoli
23-11
Lungs
• Two lungs: Principal
organs of respiration
– Right lung: Three lobes
– Left lung: Two lobes
• Divisions
– Lobes,
bronchopulmonary
segments, lobules
23-12
Ventilation
• Movement of air into and out of
lungs
• Air moves from area of higher
pressure to area of lower pressure
• Pressure is inversely related to
volume
23-13
Alveolar Pressure Changes
23-14
•Basic Chest X-Ray Interpretation
•Deb Updegraff, C.N.S
•X-rays- describe radiation which is part of the
•spectrum which includes visible light, gamma rays
and cosmic radiation.
•Unlike visible light, radiation passes through stuff.
•When you shine a beam of X-Ray at a person
•and put a film on the other side of them a shadow is
produced of the inside of their body.
•Different tissues in our body absorb X-rays at different
extents:
•Bone- high absorption (white)
•Tissue- somewhere in the middle absorption (grey)
•Air- low absorption (black)
Film Quality
• First determine is the film a PA or AP view.
PA- the x-rays penetrate through the back of the patient on to
the film
AP-the x-rays penetrate through the front of the patient on to
the film.
All x-rays in the PICU are portable and are AP view
Quality (cont.)
• Is the film over or under
penetrated if under
penetrated you will not
be able to see the
thoracic vertebrae.
Quality (cont)
• Check for rotation
– Does the thoracic spine
align in the center of the
sternum and between the
clavicles?
– Are the clavicles level?
LUNG VOLUMES
• The total volume contained in the lung at
the end of a maximal inspiration is
subdivided into volumes and subdivided
into capacities.
• There are four volume subdivisions
which:
• do not overlap.
• can not be further divided.
• when added together equal total lung
capacity.
Capacities
• Lung capacities are subdivisions
of total volume that include two
or more of the 4 basic lung
volumes.
Basic lung volumes (memorize)
• Tidal Volume (TV). The amount of
gas inspired or expired with each
breath.
• Inspiratory Reserve Volume (IRV).
Maximum amount of additional air
that can be inspired from the end of
a normal inspiration.
Basic lung volumes (memorize)
• Expiratory Reserve Volume (ERV). The
maximum volume of additional air that
can be expired from the end of a normal
expiration.
• Residual Volume (RV). The volume of
air remaining in the lung after a maximal
expiration. This is the only lung volume
which cannot be measured with a
spirometer.
Basic lung capacities (memorize)
• Total Lung Capacity (TLC). The volume
of air contained in the lungs at the end of
a maximal inspiration. Called a capacity
because it is the sum of the 4 basic lung
volumes. TLC=RV+IRV+TV+ERV
Basic lung capacities (memorize)
• Vital Capacity (VC). The maximum
volume of air that can be forcefully
expelled from the lungs following a
maximal inspiration. Called a capacity
because it is the sum of inspiratory
reserve volume, tidal volume, and
expiratory reserve volume.
VC=IRV+TV+ERV=TLC-RV
Basic lung capacities (memorize)
• Functional Residual Capacity (FRC).
The volume of air remaining in the lung
at the end of a normal expiration. Called
a capacity because it equals residual
volume plus expiratory reserve volume.
FRC=RV+ERV
Basic lung capacities (memorize)
• Inspiratory Capacity (IC). Maximum
volume of air that can be inspired from
end expiratory position. Called a
capacity because it is the sum of tidal
volume and inspiratory reserve volume.
This capacity is of less clinical
significance than the other three.
IC=TV+IRV
Now you are ready
• Look at the diaphram:
for tenting
free air
abnormal elevation
• Margins should be sharp
(the right hemidiaphram is
usually slightly higher than
the left)
Check the Heart
•
•
•
•
Size
Shape
Silhouette-margins should be sharp
Diameter (>1/2 thoracic diameter is
enlarged heart)
Remember: AP views make heart appear larger than it
actually is.
•Cardiac Silhouette
1. R Atrium
2. R Ventricle
4. Superior Vena
Cava
7. Pulmonary Valve
8. Pulmonary Trunk
Check the costophrenic angles
•Margins should
• be sharp
•Loss of Sharp
Costophrenic Angles
Check the hilar region
• The hilar – the large
blood vessels going to
and from the lung at the
root of each lung where
it meets the heart.
• Check for size and
shape of aorta,
nodes,enlarged vessels
Finally, Check the Lung Fields
•
•
•
•
•
•
Infiltrates
Increased interstitial markings
Masses
Absence of normal margins
Air bronchograms
Increased vascularity
Hemothorax
Changing Alveolar Volume
• Lung recoil
– Causes alveoli to collapse resulting from
• Elastic recoil and surface tension
– Surfactant: Reduces tendency of lungs to collapse
• Pleural pressure
– Negative pressure can cause alveoli to expand
– Pneumothorax is an opening between pleural
cavity and air that causes a loss of pleural
pressure
23-59
Pulmonary Volumes
• Tidal volume
– Volume of air inspired or expired during a normal inspiration or
expiration
• Inspiratory reserve volume
– Amount of air inspired forcefully after inspiration of normal tidal
volume
• Expiratory reserve volume
– Amount of air forcefully expired after expiration of normal tidal
volume
• Residual volume
– Volume of air remaining in respiratory passages and lungs after the
most forceful expiration
23-60
Pulmonary Capacities
• Inspiratory capacity
– Tidal volume plus inspiratory reserve volume
• Functional residual capacity
– Expiratory reserve volume plus the residual volume
• Vital capacity
– Sum of inspiratory reserve volume, tidal volume, and expiratory
reserve volume
• Total lung capacity
– Sum of inspiratory and expiratory reserve volumes plus the tidal
volume and residual volume
23-61
Spirometer and Lung
Volumes/Capacities
23-62
Minute and Alveolar Ventilation
• Minute ventilation: Total amount of air moved
into and out of respiratory system per minute
• Respiratory rate or frequency: Number of
breaths taken per minute
• Anatomic dead space: Part of respiratory
system where gas exchange does not take place
• Alveolar ventilation: How much air per minute
enters the parts of the respiratory system in
which gas exchange takes place
23-63
Physical Principles of Gas
Exchange
• Partial pressure
– The pressure exerted by each type of gas in a mixture
– Dalton’s law
– Water vapor pressure
• Diffusion of gases through liquids
– Concentration of a gas in a liquid is determined by its
partial pressure and its solubility coefficient
– Henry’s law
23-64
Physical Principles of Gas
Exchange
• Diffusion of gases through the respiratory
membrane
– Depends on membrane’s thickness, the diffusion coefficient
of gas, surface areas of membrane, partial pressure of gases
in alveoli and blood
• Relationship between ventilation and
pulmonary capillary flow
– Increased ventilation or increased pulmonary capillary blood
flow increases gas exchange
– Physiologic shunt is deoxygenated blood returning from
lungs
23-65
Oxygen and Carbon Dioxide
Diffusion Gradients
• Oxygen
– Moves from alveoli into
blood. Blood is almost
completely saturated
with oxygen when it
leaves the capillary
– P02 in blood decreases
because of mixing with
deoxygenated blood
– Oxygen moves from
tissue capillaries into the
tissues
• Carbon dioxide
– Moves from tissues
into tissue capillaries
– Moves from
pulmonary capillaries
into the alveoli
23-66
Changes in Partial Pressures
23-67
Hemoglobin and Oxygen Transport
• Oxygen is transported by hemoglobin (98.5%) and
is dissolved in plasma (1.5%)
• Oxygen-hemoglobin dissociation curve shows that
hemoglobin is almost completely saturated when
P02 is 80 mm Hg or above. At lower partial
pressures, the hemoglobin releases oxygen.
• A shift of the curve to the left because of an
increase in pH, a decrease in carbon dioxide, or a
decrease in temperature results in an increase in
the ability of hemoglobin to hold oxygen
23-68
Hemoglobin and Oxygen
Transport
• A shift of the curve to the right because of a
decrease in pH, an increase in carbon dioxide, or
an increase in temperature results in a decrease in
the ability of hemoglobin to hold oxygen
• The substance 2.3-bisphosphoglycerate increases
the ability of hemoglobin to release oxygen
• Fetal hemoglobin has a higher affinity for oxygen
than does maternal
23-69
Oxygen-Hemoglobin
Dissociation Curve at Rest
23-70
Oxygen-Hemoglobin
Dissociation Curve during Exercise
23-71
Shifting the Curve
23-72
Transport of Carbon Dioxide
• Carbon dioxide is transported as bicarbonate ions
(70%) in combination with blood proteins (23%)
and in solution with plasma (7%)
• Hemoglobin that has released oxygen binds more
readily to carbon dioxide than hemoglobin that has
oxygen bound to it (Haldane effect)
• In tissue capillaries, carbon dioxide combines with
water inside RBCs to form carbonic acid which
dissociates to form bicarbonate ions and hydrogen
ions
23-73
Transport of Carbon Dioxide
• In lung capillaries, bicarbonate ions and hydrogen
ions move into RBCs and chloride ions move out.
Bicarbonate ions combine with hydrogen ions to
form carbonic acid. The carbonic acid is
converted to carbon dioxide and water. The
carbon dioxide diffuses out of the RBCs.
• Increased plasma carbon dioxide lowers blood pH.
The respiratory system regulates blood pH by
regulating plasma carbon dioxide levels
23-74
Carbon Dioxide Transport
and Chloride Movement
23-75
Respiratory Areas in Brainstem
• Medullary respiratory center
– Dorsal groups stimulate the diaphragm
– Ventral groups stimulate the intercostal and
abdominal muscles
• Pontine (pneumotaxic) respiratory group
– Involved with switching between inspiration
and expiration
23-76
Respiratory Structures in Brainstem
23-77
Rhythmic Ventilation
• Starting inspiration
– Medullary respiratory center neurons are continuously active
– Center receives stimulation from receptors and simulation from parts of
brain concerned with voluntary respiratory movements and emotion
– Combined input from all sources causes action potentials to stimulate
respiratory muscles
• Increasing inspiration
– More and more neurons are activated
• Stopping inspiration
– Neurons stimulating also responsible for stopping inspiration and receive
input from pontine group and stretch receptors in lungs. Inhibitory
neurons activated and relaxation of respiratory muscles results in
expiration.
23-78
Modification of Ventilation
• Chemical control
• Cerebral and limbic
system
– Respiration can be
voluntarily controlled
and modified by
emotions
– Carbon dioxide is major
regulator
• Increase or decrease in pH
can stimulate chemosensitive area, causing a
greater rate and depth of
respiration
– Oxygen levels in blood
affect respiration when a
50% or greater decrease
from normal levels exists
23-79
Modifying Respiration
23-80
Regulation of Blood pH and Gases
23-81
Herring-Breuer Reflex
• Limits the degree of inspiration and
prevents overinflation of the lungs
– Infants
• Reflex plays a role in regulating basic rhythm of
breathing and preventing overinflation of lungs
– Adults
• Reflex important only when tidal volume large as in
exercise
23-82
Ventilation in Exercise
• Ventilation increases abruptly
– At onset of exercise
– Movement of limbs has strong influence
– Learned component
• Ventilation increases gradually
– After immediate increase, gradual increase occurs
(4-6 minutes)
– Anaerobic threshold is highest level of exercise
without causing significant change in blood pH
• If exceeded, lactic acid produced by skeletal muscles
23-83
Effects of Aging
• Vital capacity and maximum minute
ventilation decrease
• Residual volume and dead space increase
• Ability to remove mucus from respiratory
passageways decreases
• Gas exchange across respiratory membrane
is reduced
23-84