Chapter 15: Normal fetal lung development Flashcards
(158 cards)
What is required for normal fetal lung development?
1. Enough space in the thoracic cavity for the lungs to grow
2. Ability to inhale
- -Chest wall has to be able to move
- -Must have enough amniotic fluid
Except for the vocal cords, the entire respiratory tree is lined by what type of epithelium?
Pseudostratified columnar ciliated epithelium
Bronchia mucosa contains population of neuroendocrine cells with neurosecretory granules containing which factors?
- 1. Calcitonin
- 2. 5HT
- 3. Bombesin (gastrin releasting peptide)
Numerous mucus-secreting goblet cells and submucosal glands are dispersed throughout the walls of which parts of the respiratory tree?
Trachea and bronchi
BUT NOT BRONCHIOLES
How do normal lungs grow?
Normally from bronchus => alveoli (branching)
What 3 things do we want as our lungs grow?
- Airways to branch: larger airways will conduct the air to acinar units where gas can exchange.
- Rigid, open aiways
- Thin wall with high vascularity for gas exhchange
Diffusion distance between capilliary and basal lamina of the aveoli must be small.
Why?
Because RBC have less than one second to dump CO2 and pick up O2
What makes the wall of a aveoli?
- Capillaries with associated endothelium
- BM and interstitium.
- Type 1 pneumocytes line the aveolus
- Type 2 pneumocytes make surfactant to decrease ST and replace type 1
- Aveolar pores of Kohn
What are alveolar pores of Kohn
Pres that allow aveoli to share air with one another.
Only problem is that they also allow bacteria, cells, junk to pass between aveoli
What are the 4 congenital anomalies we will talk about?
1. Pulmonary hypoplasia
2. Foregut cysts
3. CPAM/CCAM (congeintal pulmonary adenomatoid malformation)
4. Pulmonary sequestration
Pulmonary hypoplasia occurs in utero and what are 2 major causes?
- Not enough space for lung to grow
* d/t conginital diagphragmatic hernia that pushes abdominal organs into thorax - Inability to inhale
- oligohydramnois (not enough amnoitic fluid)
- probs moving chest wall
- malformation in the airway (tracheal stenosis)
Do babies born with pulmonary hypoplasia have a good change of living?
No (95% die). If the weight of the lung is less than 40% of NL => immediately die.
Foregut cysts are?
and where do they occur most often?
Cysts from of the foregut
Hilum/middle mediastinum
Foregut cysts are most often located where in the lungs and which classification/type is most common?
Treatment?
Hilum or middle mediastinum
- Bronchogenic = most common; can also be respiratory, ESO, gastroenteric
- Excision = curative!
Histology of a foregut cysts will reveal what?
How are they discovered?
Normal respiratory epithelium, thus it is NOT a neoplasm.
By accident d/t complications: rupture, cause infection or compress airways
Congenital pulmonary adenomatoid malformations (CPAM/CCAM) are caused by what?
“Arrested development”of pulmonary tissue that forms intrapulmonary cystic peice of abnormal lung tissue THAT connect to tracheobronchial airway and pulmonary vasculature.
Via which imaging modality can congenital pulmonary adenomatoid malformations be detected?
Fetal ultrasound
Congenital pulmonary adenomatoid malformation (CPAM) can be deadly due to what?
What is a complication?
- Hydrops
- Pulmonary hypoplasia
- Infection or if it is large, it can cause pulmonary hypoplasia.
Pulmonary sequestration is what?
How is it different from CPAM?
Intra or extra-pulmonary peice of nonfunctioning lung tissue that forms into a bud but does NOT connect to the tracheobronchial airway and has its OWN blood supply.
Where do pulmonary sequestrations usually grow?
Lower left lobe (can be intralobular or extralobular)
When do intralobular pulmonary sequestration (ILS) present and what is a complication?
Older children and adults
Because ILS do not get air (even though they have their own BS), they have an increased liklihood of infection and abbsess formation (so come to ATN later)
Extralobar pulmonary sequestrations present when and come to ATN how?
How are they different from intralobular pulmonary sequestration?
- Present after birth as mass lesions and come to ATN earlier bc they bb usually has other congenital foregut anomies, especially CARDIAC and UPPER GI.
- Have their own BS, pleura and AIRWAY
What is atelectasis?
atelectasis is decreased expansion or loss of volume affecting the lungs
Atelectasis is a reversible disorder, except in cases caused by what?
Contraction atelectasis













