Download Lungs - INAYA Medical College

CHAPTER 22
The Respiratory
System:
Part B
Learning Objectives
At the end of the discussion students should be
able to:
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Recognize and contrast the anatomy of conducting
and respiratory zone of respiratory system(ILO 1.1)
Recognize and explain the anatomy of lungs and
pleura(ILO 1.2)
Learning Objectives



Recognize and contrast the histology of
various parts of respiratory system. (2.1)
Outline the development of respiratory
system(1.1)
Label the respiratory organs in the given
activity sheets. (2.2)
Lecture Outline
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Trachea
Bronchi and subdivisions
Conducting zone
Respiratory zone
Lungs
Pleurae
Developmental aspects of respiratory system
Trachea
(Windpipe)
• From the larynx into
the mediastinum
• Made up of C shaped
tracheal cartilages
Wall composed of three
layers histologically
1. Mucosa
2. Submucosa
3. Adventitia
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• Trachealis muscle
• Connects posterior
parts of cartilage rings
Posterior
Mucosa
Submucosa
Esophagus
Trachealis
muscle
Lumen of
trachea
Seromucous gland
in submucosa
Hyaline cartilage
Adventitia
Anterior
(a) Cross section of the trachea and esophagus
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Figure 22.6a
Mucosa
• Pseudostratified
ciliated columnar
epithelium
• Lamina propria
(connective tissue)
Submucosa
Seromucous gland
in submucosa
Hyaline cartilage
(b) Photomicrograph of the tracheal wall (320x)
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Figure 22.6b
Trachea
• Carina
• Last tracheal cartilage
• Point where trachea
branches into two
bronchi
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Bronchi and Subdivisions
• Air passages undergo 23 orders of branching
• Branching pattern called the bronchial
(respiratory) tree
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Conducting Zone Structures
• Trachea  right and
left main (primary)
bronchi
• Each main bronchus
enters the hilum of
one lung
• Right main
bronchus is wider,
shorter, and more
vertical than the
left
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• Each main bronchus branches into lobar
(secondary) bronchi (three right, two left)
• Each lobar bronchus supplies one lobe
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Trachea
Middle lobe
of right lung
Superior lobe
of left lung
Left main
(primary)
bronchus
Lobar
(secondary)
bronchus
Segmental
(tertiary)
bronchus
Inferior lobe
of right lung
Inferior lobe
of left lung
Superior lobe
of right lung
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Figure 22.7
Respiratory Zone
• Respiratory bronchioles
• Alveolar ducts
• Alveolar sacs (clusters of alveoli) the main site for
gas exchange
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Alveoli
Alveolar duct
Respiratory
bronchioles
Terminal
bronchiole
Alveolar duct
Alveolar
sac
(a)
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Figure 22.8a
Respiratory
bronchiole
Alveolar
duct
Alveolar
pores
Alveoli
(b)
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Alveolar
sac
Figure 22.8b
Lungs
• Occupy all of the thoracic cavity except the
mediastinum
• Root: site of vascular and bronchial attachments
• Costal surface: anterior, lateral, and posterior
surfaces
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Posterior
Esophagus
Root of lung
at hilum
• Left main bronchus
• Left pulmonary artery
• Left pulmonary vein
Heart (in mediastinum)
Sternum
Anterior
(c) Transverse section through the thorax, viewed from above.
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Figure 22.10c
Lungs
• Apex: superior tip
• Base: inferior surface that rests on the diaphragm
• Hilum: on mediastinal surface; site for attachment
of blood vessels, bronchi, lymphatic vessels, and
nerves
• Cardiac notch of left lung: concavity that
accommodates the heart
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Lungs
• Left lung is smaller,
separated into two
lobes by an oblique
fissure
• Right lung has three
lobes separated by
oblique and horizontal
fissures
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• Bronchopulmonary segments (10 right, 8–9 left)
• Lobules are the smallest subdivisions; served by
bronchioles and their branches
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Right lung
Right
superior
lobe (3
segments)
Left lung
Left superior
lobe
(4 segments)
Right
middle
lobe (2
segments)
Right
inferior lobe (5 segments)
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Left inferior
lobe (5 segments)
Figure 22.11
Trachea
Thymus
Lung
Intercostal
muscle
Rib
Parietal pleura
Pleural cavity
Visceral pleura
Apex of lung
Right superior lobe
Horizontal fissure
Heart
(in mediastinum)
Right middle lobe
Oblique fissure
Right inferior lobe
Diaphragm
Base of lung
Left
superior lobe
Oblique
fissure
Left inferior
lobe
Cardiac notch
(a) Anterior view. The lungs flank mediastinal structures laterally.
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Figure 22.10a
Pleurae
• Thin, double-layered serosa
• Parietal pleura on thoracic wall and superior face
of diaphragm
• Visceral pleura on external lung surface
• Pleural fluid fills the slit like pleural cavity
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Developmental Aspects
• Tracheal bud starts developing from the pharynx
at the start of 4th week of development
• By 8th week of development right and left lungs
can be defined in lobes.
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Future mouth
Frontonasal
elevation
Olfactory
placode
Eye
Foregut
Stomodeum
(future mouth)
Laryngotracheal
bud
(a) 4 weeks: anterior
superficial view of
the embryo’s head
Pharynx
Trachea
Olfactory
placode
Esophagus
Liver
Bronchial
buds
(b) 5 weeks: left lateral view of the developing lower
respiratory passageway mucosae
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Figure 22.28
KEY POINTS
• Trachea
Windpipe: from the larynx into the mediastinum
Trachealis muscle, Carina
• Bronchi and subdivisions
23 orders of branching, Branching pattern called the
bronchial (respiratory) tree
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KEY POINTS
• Conducting zone structures
Trachea, Main bronchus, branches of main bronchus,
bronchioles, terminal bronchioles
• Respiratory zone
Respiratory bronchioles, alveolar ducts, alveolar sacs
(clusters of alveoli), the main site for gas exchange
• Lungs
Root, Costal surface: anterior, lateral, and posterior
surfaces , Apex, Base, Hilum, Cardiac notch
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KEY POINTS
• Right lung, Left lung, Bronchopulmonary segments,
lobules
• Pleurae
Thin, double-layered serosa
Parietal pleura on thoracic wall and superior face of
diaphragm
Visceral pleura on external lung surface
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KEY POINTS
• Developmental aspects of respiratory system
Tracheal bud starts developing from the pharynx at the
start of 4th week of development
By 8th week of development right and left lungs can be
defined in lobes.
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ANY QUESTIONS??????
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