Transcript Lymphatic & Immune System

Respiratory
System
Respiratory
System
• Respiratory system
provides for gas
exchange.
• Respiration
– Internal
– External
• Ventilation
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Respiratory
System
• Upper respiratory
system
– Nose
– Pharynx
• Lower respiratory
system
– Larynx
– Trachea, etc
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Respiratory
System
• Conducting portion
– Series of tubes
descending in size.
• Respiratory portion
– Area of gas
exchange.
– alveoli
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Passage of Air
Through the Nose
• Functions of nose.
– Warms, moistens, and
filters the air.
– Olfactory senses.
– Resonance chamber for
sounds.
• Role of turbinates.
• Role of mucus.
• Role of Cilia
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Pharynx
• Nasopharynx
• Oropharynx
• Laryngopharynx
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Respiratory
Tree
• Trachea
– Supported by cartilage.
– Lined with mucous
membrane.
– Lined by ciliated,
pseudostratified
columnar epithelium.
• Primary bronchi
• Secondary bronchi
• Tertiary bronchi
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Bronchioles
• Not supported by
cartilage rings.
• Smooth muscle in
walls.
• ANS controls
diamenter of
bronchiloes.
• Asthma: smooth
muscle spasms.
• Bronchioles end in
alveoli.
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Structure of
the Lungs
• Lungs lie in
thoracic cavity.
• Lungs surrounded
by double
membrane (Pleural
membrane)
– Secretes
lubricating fluid.
– Creates an air tight
thoracic cavity.
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Structure of
the Alveoli
• Cup shaped pouches
that make up an air
sac.
• Lined with simple
squamous epithelium
connected to a
basement
membrane.
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Structure of
the Alveoli
•
•
•
•
Macrophages
Septal cells
Role of surfactant.
Alveoli are
surrounded by
capillaries.
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Pulmonary
Ventilation
• Air moves due to
differences in
pressure inside
compared to outside
the thoracic cavity.
• Air moves from high
to low pressure
areas.
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Pulmonary Ventilation:
Inhalation
• Atmospheric pressure =
760 mmhg.
• If thoracic air pressure
equals 760 mmhg, no air
will move in or out.
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Pulmonary Ventilation:
Inhalation
• To enlarge the thoracic
cavity and create a low
pressure:
– Contract (pull down) the
diaphragm.
– External intercostal
muscles contract (pulls rib
cage up and out).
• Alveolar air pressure drops
2 mmhg. (758 mmhg)
• Air fills lungs.
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Pulmonary Ventilation:
Exhalation
• Reducing the thoracic cavity
size creates higher air
pressures.
• To create a higher thoracic
cavity:
– Diaphragm relaxes.
– Rib cage moves down and in.
– Elasticity of lungs causes
them to empty
– Contracting abdominal
muscles force internal
organs up.
– Pressure rises to 762
mmhg.
Wednesday 4/9/03
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Surfactant
• Phospholipid.
• Produced by the septal
cells.
• Reduces surface
tension.
• The ability to easily
inflate and deflate is
“compliance”.
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Pulmonary Volumes
• Measured using a
spirometer.
• Recording of
volumes is called
a spirogram.
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Pulmonary Volumes
• Tidal volume
–
–
–
–
(TV)
Inhalation or exhalation
while at rest.
500 ccm.
350ccm reach alveoli.
Rest is in dead air space.
• Minute volume of
respiration: (MVR)
– Tidal volume x inhalations
per minute.
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Pulmonary Volumes
• Inspiratory reserve
volume. (IRV)
– Amount of air that can be
inhaled after tidal volume.
– 2500 to 3500 ccm.
• Expiratory reserve.
(ERV)
– Amount of air tht can be
exhaled after normal
exhalation.
– Approx. 1200 ccm.
Pulmonary Volumes
• Residual volume (RV)
– Volume of air that
cannot be exhaled.
– 1200 ccm.
• Minimal air (vital air)
– Air that clings to lung
tissue after first
breath.
Pulmonary Capacities
• Inspiratory capacity (IC)
– Tidal volume + inspiratory
volume.
• Expiratory capacity (EC)
– Tidal volume + expiratory
volume.
• Vital capacity (VC)
– Tidal volume + inspiratory
reserve volume + expiratory
reserve volume.
Pulmonary Capacities
• Total Lung Capacity (TLC)
• Combination of:
– Inspiratory volume
– Tidal Volume
– Expiratory volume
– Reserve volume
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Exchange of
Respiratory Gases
• Oxygen and carbon dioxide
move from areas of high
partial pressure to areas of
low partial pressure.
• A gases partial pressure (p)
is equal to the percentage of
that gas in a mixture.
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Transport of
Respiratory Gases
• Function of blood is
transport of gases.
• Transports from
lungs to tissues.
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Transport of
Respiratory Gases
• Transport of oxygen
– 1.5% dissolves into
plasma of blood.
– 98.5% combines with
hemoglobin to form
oxyhemoglobin.
Hb + O2 ------- HbO2
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Transport of
Respiratory Gases
• Transport of carbon
dioxide
• 7% dissolves into plasma.
• 23% combines with
hemoglobin to form
carbaminohemoglobin.
• 70% transported in
plasma as carbonic acid.
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Transport of
Respiratory Gases
• Factors regarding
oxygen being
released by
hemoglobin;
– pH
– Temperature
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Transport of
Respiratory Gases
• Carbon monoxide.
– Binds to hemoglobin
200X more strongly
than O2.
CO Poisoning results
because hemoglobin
cannot carry oxygen
if it’s bound to CO.
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Control of Respiration
• Role of respiratory
center in brain stem.
• Medullary rhythmicity
– Medulla oblongata
– Controls breathing
rhythym
• Pneumotaxic Area
– Pons
– Limits inhalation
• Apneustic Area
– Lower pons
– Lengthens inhalation
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Factors that
Increase Respiration
• Increase in arterial blood
PCO2.
• Decrease in arterial
blood PO2.
• Decrease in blood
pressure
• Increase in body
temperature
• Prolonged pain.
• Stretching of sphincter.
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