Lung Path 1 - Embryo Histo Malformation Atelactasis Edema ARDS (Singh) Flashcards
Requirements for normal fetal lung development?
Space in the thoracic cavity for growth (lungs are soft and cannot compete for additiona room, if it is not provided)
Enough room for the chest wall to be able to move (again, due to paranchymal softness)
Sufficient amount of amniotic fluid for inhalation to occur
What are the rigidly open structures of the airway and what is these sections primarily role?
Trachea
Main bronchus (primary)
Lobar bronchus (secondary)
Segmental bronchus (tertiary)
Their fxn is to conduct air to the terminal acinar units
What structures have thin walls and high vascularity?
What is their function?
Bronchioles
Terminal Bronchioles
Respiratory Bronchioles
Fxn of resp bronchioes: Gas Exchange
Except for the vocal cords, the entire respiratory tree is lined by what type of epithelium?
Pseudostratified, tall, columnar, ciliated epithelium
How will respiratory tissue appear histologically?
Mucosal epithalium is inner most layer (cillia, goblet cells, submucosal glands)
Muscularis mucose - smooth muscles, provide peristalsis
Bronchial ring - provides rigidity
Numerous mucus-secreting goblet cells and submucosal glands are dispersed throughout the walls of which parts of the respiratory tree?
- Trachea
- Bronchi
- NOT the bronchioles
Bronchial mucosa contains population of neuroendocrine cells with neurosecretory granules containing which factors?
- Serotonin
- Calcitonin
- Gastrin-releasing peptide (bombesin)
What are 2 functions of the Type 2 pneumocytes of the alveolar epithelium?
Type 2 pneumocytes are puliprotent
- Produce surfactant
- Repair of alveolar epithelium by giving rise to type 1 pneumocytes
What are the components of the Interstitium?
Alveolar epithelium
Fused basal laminae of the alveolar epithelium and the capillary endothelium
Capillary endothelium
What is the significance of alveolar pores?
What are they called?
Alveolar pores may also be referred to as “Pores of Kohn”
They conduct air (somehwat redundant) between alveoli –> good
Also allow the spread of bacteria and cancer cells to be exchanged between alveolar cells –> not so great
What plays a particularly important role in the synthesis of surfactant?
Glucocorticoids
Analysis of what in the amniotic fluid provides a good estimate of the level of surfactant in the alveolar lining?
Phospholipids
Pulmonary hypoplasia occurs in utero and what are 2 major causes?
- Congenital diaphragmatic hernia
- Inability to inhale
- Oligohydramnios (d/2 renal agenesis) Must know Potter Sequence!
- Airway malformation (stenosis)
- Chest wall motion disorders
–> high mortality rate
Foregut cysts are most often located where in the lungs and which classification/type is most common?
Complications?
Treatment?
Hilum or middle mediastinum
Bronchogenic cysts of the respiratory lining are most common
but can be esophageal or gastroenteric
Complications: rupture, infection, or pushing/compressing airway
Treatment: Excision curative!
What are some histologic findings on an excised bronchogenic cyst?
Typical respiratory lining filled with humorous substance
Congenital pulmonary adenomatoid malformations (CPAM/CCAM) are caused by what?
“Arrested development” of pulmonary tissue –> formation of intrapulmonary cystic masses WITH connection to tracheobronchial airways and pulmonary vasculature
No differentiation! Cell division is stuck in one development stage, and keeps reproducing the same cell line.
Congenital pulmonary adenomatoid malformations can be deadly due to what complications?
What is unique about this developmental disorder if discovered early in-utero?
- Hydrops or pulmonary hypoplasia
- Can get infected later in life
Can be removed in-utero –> corrects course of development by removing the “irregular, lumpy tumor” and making space in the thoracic cavity
Pulmonary sequestration refers to a discrete area of lung with what 2 features?
Non-functioning lung tissue forming abberant “lung bud” that
- Lacks any connection to the airway system
- Has abnormal blood supply arising from aorta or its branches
When do intralobal pulmonary sequestrations typically present and are often due to what?
Older children/adults
Due to recurrent localized infection or bronchiectasis due to “stasis” caused lack of airway
Extralobar pulmonary sequestrations most commonly come to attention in infants how?
As mass lesions in the chest or abdomen
Usually associated w/ other congenital anomalies
May have independent airways
Via which imaging modality can congenital pulmonary adenomatoid malformations be detected?
Fetal ultrasound
What are the differences between CPAM and Pulmonary sequesteration?
CPAM
always inrapulmonary
connection to airways and pum vasculature
Sequesteration
intra- or extrapulmonary
NO connection to bronchial tree of pulm vasculature
What are the 3 main types of acquired atelectasis and what is each caused by?
- Resorption due to obstruction of airway (mucus plugs) which gradually reduces lung expansion
- Compression due to accumulation of material or air/material within pleural cavity (i.e., transudate/exudate/blood or pneumothorax) that compresses the parenchyma
- Contraction due to fibrosis or restrictive processes in pleura preventing the lungs from filling completely