L5 Development Of LRT And The Diaphragm Flashcards
What are the components of URT and LRT ?
URT :
- Nasal cavity
- Pharynx
LRT :
- Larynx
- Trachea
- Main bronchi
- Lungs
What is intra-embryonic coelom ?
It is the cavity with in the embryo in the lateral plate of intra-embryonic mesoderm which developed by dividing the lateral plate mesoderm of the embryo into somatopleuric and splanchnopleuric mesoderm.
It will give the body cavities later on
What will happen after the development of intra-embryonic ceolem ?
- The upper half called somatopleuric, made of :
- somatopleuric mesoderm
- ectoderm - The lower half called splenchnopleuric, made of :
- splanchnopleuric mesoderm
- endoderm
To what the intra-embryonic ceolem will divide to ?
It is a horse-shoe cavity that give rise to:
- Pericardial ceolem ( pericardium later )
- Percardio-peritonial canal ( left and right pleura later )
- Peritoneal ceolem ( peritoneumlater )
What is septum transversum ?
It is the unsplit part of the intraembryonic mesoderm
Before head fold formation it lies cranial to pericardial cavity.
After head fold formation, it lies caudal to pericardial cavity and ventral to foregut.
Later on septum transversum will take part in diaphragm formation ( the central tendon )
What are the structures that contribute in the development of the diaphragm ?
- Plueroperitoneal membrane ( posterolateral part )
- Esophageal mesentry ( crura )
- Septum transversum ( central tendon )
- Muscular growth from body wall ( muscular part at periphery )
What is the function of plueroperitonial membrane ?
Separating the peritoneum from pericardio-peritoneal canal
What is the innervation of the diaphragm ?
MOTOR
- whole diaphragm is by phrenic nerve C3-5
SENSORY
- most of the diaphragm is by the phrenic nerve
- the peripheral regions are by intercostal nerves
What are the most common anomalies of the diaphragm?
They are mostly related to the posterolateral region ( plueroperitoneal membrane )
- Absence of the membrane
- Weakness in this area which will cause ( eventarion of the diaphragm )
What is laryngotracheal groove?
A small median groove develops in the floor of the developing pharynx
Epithelial proliferation of Laryngotracheal groove give rise to epithelium and glands of
- larynx
- trachea
- bronchi
- pulmonary epithelium ( lungs )
So it is responsible on the formation of LRT
What does the mesenchyme form ?
It will give
- cartilage
- muscles
- blood vessels
What does hypobronchial eminence will give rise to ?
Cranial part :
- the tounge
Caudal part ( 3rd + 4th ) : - epiglottis
How trachea is developed?
- Laryngotracheal groove
- Laryngotracheal tube
- Trachea develop as resp. diverticulum from the tube that has lung buds in their caudal ends
- Tracheo-esophageal ridge come close together to fuse and separate both trachea and esophagus
What are the tracheal development anomalies?
- Tracheoesophageal Fistula
- Laryngotracheoesophageal cleft
- Tracheal Stenosis and Atresia (Narrowing of trachea)
- Tracheal Diverticulum ( outgrowth from the trachea as it is soft earlier )
What are the main stages of lung development ?
- Pseudoglandular Period (5 – 17weeks)
* cuboidal cells
* no alveoli
* no contact between the vessels and the bronchioles - Canalicular Period (16- 25 weeks)
* more flattened cells
* alveolar ducts are formed
* Highly vasculrized - Terminal sac Period (24 weeks – birth)
* completely squamous
* terminal sac formation
* pneumocyte I ans II are formed and surfactant produced
* Intimate contact between epithelial and endothelial cells established - Alveolar Period (Late fetal Period to child hood)
* formation of alveoli and increase in number
