Devt of Respiratory system Flashcards
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In the formation of the primitive gut tube, the embryo folds in two directions. These are?
Cephalodcaudal and lateral folds
The primitive gut tube is formed by
A portion of yolk sac lined by endoderm, which is now internalized
Development of respiratiory diverticula begins in week
4
How foes it develop
Proliferation of the endodermal epithelium of the ventral part of the foregut(laryngotracheal groove) into mesenchyme
Respiratory epithelium develops from?
Endodermal tube
The rest of resporatory wall develop from?
Sphlanchnic mesoderm surrounding the foregut
Diverticulum bifurcates to form
Primary bronchial(lung) buds
How are the lung buds separated from the foregut
By two longitudinal ridges closing off communication. Tracheosophageal ridge.
These ridges fuse to form the tracheo oesphageal septum
Foregut is then separated into
Dorsal oesophagus and ventral trachea and lung buds
Initially, the lung is a space called
Pericardioperitoneal canals
Sufficient mature terminal sac are present at end of
Terminal sac
Type two aveolar cells secrete surfactant at
End of sixth month
What causes the induction of the respiratory tree
An increase in the retinoic levels in the endoderm, which causes an increase in the expression of transcription factor TBX4 in the endoderm
Wnt signaling necessary for the formation of the respiratory tree
Tracheomalacia and Bronchiomalacia
Cartilage around them not forming properly
Diaphragm is formed by fusion of
Septum transversum
Peripheral rim derived from body wall
Pleuroperitoneal membranes
Dorsal oesophageal mesentry
Diaphragm supplied by
Phrenic nerve
Level of inferior vena cava, oesophagus, and aorta
8 10 12
Stages of development of respiratory system
Embryonic Pseudoglandular Canalicular Saccular Alveolar
What is polyhydramnios
Baby isn’t swallowing fluid in uterus so fluid stays and becomes really large around baby
What influences induction of the development of the respiratory system
Retinoic level in mesoderm increased.
Causes increased expression of transcription factor TBX4 in the endoderm
Wnt signaling necessary for respiratory tree formation
Surfactany primarily composed of
Phospholipids
Note
Alveolar development is a post natal phenomenon
Division of bronchioles continues up to
7th prenatal month. Canalicular phase
Sufficient mature terminal sac present at?
End of 7th month
How much of alveoli is present at birth
1/6
