Transcript Respiratory System

Objectives
• 1. Define and explain “respiration.”
• 2. Identify the organs of the respiratory
system and how each plays a role in gas
exchange.
• 3. Describe the mechanisms by which oxygen
and carbon dioxide are transported by blood.
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Objectives
• 4. Describe the structure of the larynx
and its role in phonation.
• 5. Identify and describe the structures
and divisions of the respiratory tree.
• 6. Identify layers, lobes and segments
of the lung.
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Objectives
• 7. Explain the relationship between the
lung and other structures within the
thoracic cavity.
• 8. Explain the microscopic relationship
between lung and vascular structures
and how gases are exchanged.
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Objectives
• 9. Describe the neural and chemical control
mechanisms of respiration.
• 10. Define and discuss the etiology,
symptoms and treatment of the following
respiratory disorders; Bronchitis, coryza,
emphysema, asthma, lung cancer,
tuberculosis, respiratory distress syndrome,
SIDS, cystic fibrosis, CO poisoning, pleurisy,
pulmonary embolism and pulmonary edema.
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Objectives
• 11. Define and use the correct
terminology associated with the
respiratory system.
• 12. Discuss the effects of aging on the
respiratory system.
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Respiratory System
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Respiration Definitions
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•
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•
Breathing/pulmonary ventilation
External respiration
Cellular respiration
Internal respiration
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Breathing/pulmonary
Ventilation
• Process of gas exchange between
atmosphere and lungs
– Oxygen intake
– Carbon dioxide elimination
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External Respiration
• Exchange of gases between lungs and
blood
• Driven by concentration gradients
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Cellular Respiration
• Energy production via transformation of
biological compounds within the
mitochondria
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Internal Respiration
• Exchange of O2 and CO2 between
blood and tissue cells
• Driven by concentration gradients
• Mechanisms of oxygen and carbon
dioxide transport in blood
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Oxygen Transport
• Primarily as oxyhemoglobin
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Carbon Dioxide
Transport
• Three ways
• CO2 +H2O -------->H2CO3------->HCO3- + H+
– in plasma
– carbonic anhydrase enzyme required
– 67%
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Carbon Dioxide
Transport
• CO2 + Hb = carbamino compound
• 25%
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Carbon Dioxide
Transport
• CO2 dissolved gas in plasma
8%
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Respiratory Organs
•
•
•
•
•
•
Conducting portion
Nose
Pharynx
Larynx
Trachea
Bronchi
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Nose - External
• Nasal bones
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Nose - External
• Hyaline cartilage
– 3 parts
• Lateral
• Alar
• Anterior septum
• Muscle (nasalis)
• Skin
• Mucous membrane
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Nose - External
• External nares/nostrils
• Open into vestibule
– Lined with skin, hairs
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Nose – Internal
• Boney cavity
• Superior meatus(conchae) – ethmoid
• Middle meatus – ethmoid
• Inferior meatus - turbinate/inf. Nasal conchae
• Create turbulence to warm, moisten and
clean air as it passes over mucous
membrane
– Lined with ciliated mucous membrane
– Contains olfactory cells
– Moves mucus out of cavity
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Nose
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Nose
• Internal nares/choanae open into
pharynx
– Receives secretions from sinuses, lacrimal
duct
– Divided into right and left halves via
septum formed by
• Vomer
• Ethmoid (perpendicular plate
• Cartilage
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Pharynx
• Funnel-shaped space between nasal
cavity and larynx
• Passage for air, food, resonating
chamber
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Pharynx
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Pharynx
• 3 divisions
• Nasopharynx
– Internal nares to
soft palate
– Contains
eustachian tube
openings,
pharyngeal
tonsils/adenoids
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Pharynx
• Oropharynx
– Soft palate to
hyoid
– Entered from
mouth via
fauces
– Contains
palatine and
lingual tonsils
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Pharynx
• Laryngopharynx
– Hyoid bone to
larynx and
esophagus
– Common
passageway for
respiratory and
digestive system
– Skeletal muscle
covered by
mucous
membrane
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Larynx
• Framework of nine hyaline and elastic
cartilages
• Thyroid
• Cricoid
• Epiglottis (elastic cartilage)
• 2 arytenoid
• 2 corniculate
• 2 cuneiform
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Larynx
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Larynx
• Begins at hyoid bone
• Lined with ciliated mucous
membrane
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Larynx
• 2 pairs of lateral folds
– Superior ventricular folds/false vocal cords
– Inferior aryepiglottal folds/true vocal cords
• Space between true and false vocal
cords = ventricle
• Space between 2 true cords = glottis
• Intrinsic and extrinsic muscles
• Sound quality affected by age & gender
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Larynx
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Vocal Folds
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Larynx Model
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Trachea
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Trachea
• Anterior to esophagus
• 12-15 cm long
• 16-20 “C” shaped
cartilaginous rings form
flexible framework
• Enclosed posteriorly by
trachealis muscle
• Lined with ciliated
mucous membrane
• Divides at carina
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Trachea Cross Section
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Bronchi
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Bronchi
• Right and left branches
• Cartilage rings and pieces
• Lined with ciliated mucous membrane
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Bronchi
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Subdivide into
Secondary/lobar bronchi
Tertiary/segmental bronchi
Bronchioles
Terminal bronchioles
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Respiratory Portion
• Respiratory bronchioles
• Alveolar ducts
• Alveoli
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Lobule
Model
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Lungs
• In thoracic cavity separated by
mediastinum
• Surrounded by visceral pleura
• Cavity lined with parietal pleura
• Medially attached to bronchi at root
• Broad inferior base
• Superior apex
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Lungs
• Right and left
lungs differ:
• Left has
cardiac notch
• Left has 2
lobes
separated by
oblique fissure
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Lungs
• Right has 3 lobes separated by oblique
and horizontal fissures
• Each has 10 bronchopulmonary
segments served by segmental/tertiary
bronchi
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Lung
Lobes
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Bronchial Tree
• Trachea
– Primary bronchi
• Secondary bronchi
– Tertiary bronchi
» Bronchiole
»
Terminal bronchiole
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Lung Lobules
• Each segment
divided into lobules
• Lobules consist of
respiratory
bronchiole, alveolar
duct, alveolar sac,
alveolus
• Alveoli coated with
surfactant to
enhance gas
exchange
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Bronchopulmonary
Segment
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Alveolus
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Alveoli
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Breathing Mechanics
• Air moves along pressure gradient
• Pressure and volume inversely related
(PV=nRT)
– Air moves into system as cavity volume increases
and pressure decreases
– Volume increases normally due to contraction of
• Diaphragm
• External intercostals
• .Strenuous breathing may also involve
– Sternocleidomastoid, pectoralis minor and scalene
muscles
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Breathing Mechanics
• Inspiration/inhalation occurs when pressure
inside thoracic cavity < atmospheric pressure
• Expiration/exhalation normally occurs as a
passive process
• Rebound of elastic fibers in system
• External intercostals and diaphragm relax
• Forced expiration recruits internal
intercostals, abdominal muscles
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Emphysema
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Emphysema X-ray
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Emphysema Alveoli
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Control of Respiration
• Neural
• Chemical/physical
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Neural Control
• Three centers in pons and medulla
• Pneumotaxic center in pons
– Regulates rhythm
– Inhibits apneustic center
• Apneustic center in inferior pons
– Regulates inspiratory drive
– Stimulates inspiratory center in medulla
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Neural
Control
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Neural
• Medullary center
– inspiratory center
– Stimulates diaphragm and external
intercostals
– Expiratory center
– Active only during forced expiration
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Chemical Control
• Chemical and physical influences
• Central chemoreceptors in medulla
• Peripheral chemoreceptors in carotid
artery, Aorta
– Measure CO2 in blood and CSF
• Stretch receptors in lung
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Chemical Control
• Cortical influences
– Detect and report inflated condition of
lung
– Voluntary disruption of normal brain
stem regulation
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