Respiratory System (Severson) - W1 Flashcards
Where and from what does the laryngotracheal groove develop from?
ventral wall of the primitive pharynx, caudal to the 4th pair of phayrngeal arches.
What is derived from endoderm?
- epithelium of lARYNX, TRACHEA AND BRONCHI
- glands
- pulmonary epitheilum
What is derived from splanchnic mesenchyme?
- connective tissue
- cartilage
- smooth muscle
What does laryngeal cartilage develop from?
Neural crest mesenchyme
What does the laryngotracehal tube form from?
cranial part of foregut - tracheoesophageal folds and septum divide it.
Where is the epitheial lining of the larynx derived from?
endoderm
What are laryngeal cartilages derived from?
4th and 6th pharyngeal arches (mesenchyme derived from neural crest cells)
What do laryngeal muscles develop from and what are they innervated by?
develop from myoblasts of 4th and 6th pair of pharyngeal arches.
Innervated by vagus nerve - superior laryngeal and recurrent laryngeal nerves
How is the trachea formed?
Formed by separation of the foregut into the trachea and esophagus by growth of the tracheoesophageal fold & septum.
in the trachea, where are epithelium and glandular elements derived from?
Endodermal origin
In the trachea, where are cartilage, connective tissue, and muscle derived from?
splanchnic mesoderm
Explian what a tracheosophageal fistula is and what it is associated with
abnormal communication between trachea and esophagus.
Associated w/esophageal atresia.
What causes a tracheoesophageal fistula?
What are complications?
- caused by: abnormal partitioning of the laryngotracheal tube by the tracheoesophageal septum
- complications
- pneumonia from food or gastric contents entering lungs
- polyhydramnios due to amnitoic fluid accumulation - can’t pass to stomach for reabsoprtion.
What does the primary bronchial bud grow into?
pericardioperitoneal canals
in the bronchi and lungs, what is derived from the splanchnic mesoderm
- cartilaginous plates
- bronchial smooth muscle
- connective tissue
- pulmonary connective tissue
- pulmonary capillaries
What is the Parietal pleura derived from?
Somatic mesoderm
What is the visceral pleura derived from?
Splanchnic mesoderm
How is an azygous lobe formed?
part of the superior lobe of the right lung grows MEDIAL to the azygous vein instead of lateral to it.
What is lung hypoplasia usually associated with?
Congenital diaphgramatic hernia
What is another cause besides congential hernia that can cause pulmonary hypoplasia
Oligohydramnios
What can cause oligohydramnios?
- insuffiencent amount of fluid
- bilateral renal agenesis - urine is diminished reducing the amount of amniotic fluid
What is seen with Potter’s syndrome?
pulmonary hypoplasia and bilateral renal agenesis
T/F. Bronchioles have cartilage.
False, just the bronchi do.
4 stages of lung development
-
Pseudoglandular stage - 6-16 weeks
- bronchi and terminal bronchioles form
- no alveoli
-
Canalicular stage - 16-26 weeks
- vascularization and respiration possible
- respiratory bronchioles and alveolar ducts develop
-
Terminal sac period 26 weeks to birth
- alveolar cells form - surfacant
- capillary and lymph vessels form
-
alveolar period - late fetal to 8 years
- maturation of alveoli
- thin respiratory membrane
- aveloli increase
What are type I alveolar cells made up of?
squamous epithelium of endodermal origin
What do type II alveolar cells produce?
surfactant
(phospholipids and 2 proteins)
leads to lower surface tension at air-alveolar interface
What is featl breathing movements and when do they occur?
FBMs occur prior to birth and are essentail for normal lung development.
Stimulate lung development and facilitates development of respiratory muscles.
What are 3 ways removal of amniotic fluid occurs at birth?
- through mouth and nose by pressure on thorax during vaginal deliveries
- into pulmonary arteries, veins and capillaries
- into the lymphatics
What is respiratory distress syndrome?
- deficiency of surfactant and injury to alveolar wall
- leads to protein rich fibrin-rich exudate into alveolar space and formation of hyaline membranes
what administered during pregnancy can accelerate fetal lung development
glucocorticodis (B-methasone)
Why do stillborn infant’s lungs sink in water?
they contain fluid, not air.
When does pulmonary surfactant formation occur?
20 weeks but not sufficient until 26-28 week.
What are congenital lung cysts?
- form by DILATION of terminal bronchioles due to distrubance in bronchial development during LATE fetal life
- lungs have HONEYCOMB appearance
