A well summarized presentation on the Basics in the science of the Human Anatomy that'll effectively deliver information in an incredibly remarkable way to the reader.
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
DEVELOPMENT OF RESPIRATORY SYSTEM by Shapi. MD.pdf
1. HUMAN ANATOMY
• EMBRYOLOGY
• DEVELOPMENT OF THE
RESPIRATORY SYSTEM
• Dr. Chongo Shapi, (BSc. HB, MBChB)
• Medical Doctor
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2. FORMATION OF THE LUNG BUDS
• In 4 weeks old embryo, the respiratory
diverticulum (lung bud) appears as an outgrowth
from the ventral wall of the foregut.
• Epithelium of the internal lining of the larynx,
trachea, and bronchi, as well as that of the lungs,
is entirely of endodermal origin.
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4. FORMATION OF THE LUNG BUDS
• The cartilaginous, muscular, and connective tissue
components of the trachea and lungs are derived
from splanchnic mesoderm surrounding the
foregut.
• Two tracheoesophageal folds fuse to form the
tracheoesophageal septum which divides the
foregut into a dorsal portion, the esophagus, and
a ventral portion, the trachea and lung buds.
• This septum divides the cranial part of the foregut
into a ventral part, the laryngotracheal tube and a
dorsal part, oropharynx and esophagus
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7. DEVELOPMENT OF LARYNX
• The internal lining of the larynx: From
Endoderm
• The cartilages and muscles: From
mesenchyme of the 4th and 6th Pharyngeal
arches.
• Proliferating mesenchyme of the two arches
transforms into the thyroid, cricoid, and
arytenoid cartilages.
• Temporary occlusion of the laryngeal lumen
occurs due to the proliferation of laryngeal
epithelium.
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8. DEVELOPMENT OF LARYNX
• Recanalization produce a pair of lateral recesses,
the laryngeal ventricles (recesses are bounded by
folds of tissue that differentiate into the false and
true vocal cords)
• Since musculature of the larynx is derived from
mesenchyme of the 4th & 6th pharyngeal arches, all
laryngeal muscles are innervated by branches of
the 10th cranial nerve (vagus nerve).
• The superior laryngeal nerve innervates derivatives
of the fourth pharyngeal arch, and the recurrent
laryngeal nerve innervates derivatives of the sixth
pharyngeal arch.
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9. Development of Larynx
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Pharyngeal arches: Each arch contains a cartilaginous component, a
cranial nerve, an artery, and a muscular component.
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12. DEVELOPMENT OF TRACHEA, BRONCHI & LUNGS
• During its separation from the foregut, the lung bud
forms the trachea and two lateral outpocketings, the
bronchial buds.
• At the beginning of the 5th week, each of these buds
enlarges to form right and left main bronchi.
• The right then forms three secondary bronchi, and
the left, two.
• By the end of the 6th month, approximately 17
generations of subdivisions have formed.
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13. DEVELOPMENT OF TRACHEA, BRONCHI & LUNGS
▪ Before the bronchial tree reaches its final shape,
however, an additional six divisions form during
postnatal life.
▪ As the lungs develop they acquire a layer of visceral
pleura from splanchnic mesenchyme
▪ The thoracic body wall becomes lined by a layer of
parietal pleura derived from the somatic mesoderm
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20. • Scattered among the squamous epithelial cells are rounded secretory epithelial cells, type
II alveolar cells or pneumocytes
• Type II pneumocytes secrete a mixture of phospholipids called surfactant
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MATURATION OF THE LUNGS
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21. DEVELOPMENT OF PLEURA
• The pleuroperitoneal and pleuropericardial folds
separate the pericardioperitoneal canals from the
peritoneal and pericardial cavities, respectively, and
the remaining spaces form the primitive pleural
cavities.
• The splanchnic mesoderm, which covers the outside
of the lung, develops into the visceral pleura.
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22. DEVELOPMENT OF PLEURA
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Growth of the lung buds into the pericardioperitoneal canals.
Note the pleuropericardial folds.
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24. DEVELOPMENT OF PLEURA
• The somatic mesoderm layer, covering the body
wall from the inside, becomes the parietal pleura.
• The space between the parietal and visceral pleura
is the pleural cavity.
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The Visceral and Parietal Pleura
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26. CONGENITAL ANOMALIES OF THE RESPIRATORY
SYSTEM
• Abnormalities in partitioning of the esophagus
and trachea by the tracheoesophageal septum
result in esophageal atresia with or without
tracheoesophageal fistulas (TEFs).
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28. CONGENITAL ANOMALIES OF THE RESPIRATORY
SYSTEM
▪ Respiratory distress syndrome (RDS) or
(Hyaline membrane disease): When surfactant is
insufficient,
the air-water (blood) surface membrane tension becomes
high,
so alveoli will collapse during expiration.
▪ Blind-ending trachea with absence of lungs.
▪ Agenesis of one lung.
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29. CONGENITAL ANOMALIES OF THE
RESPIRATOR SYSTEM
• Abnormal divisions of the bronchial tree.
• Ectopic lung lobes arising from the trachea or
esophagus from additional respiratory buds of
the foregut that develop independently of the
main respiratory system.
• Congenital cysts of the lung, which are formed
by dilation of terminal or larger bronchi.
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