Respiratory Embryology Flashcards Preview

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Flashcards in Respiratory Embryology Deck (48)
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1
Q

Where does the respiratory system begin its growth?

A

Median outgrowth of laryngotracheal groove

2
Q

What happens to the outgrowth of laryngotracheal groove?

A

The groove evaginates to form the laryngotracheal diverticulum that will elongate

3
Q

What forms at the distal end of the laryngotracheal diverticulum?

A

Respiratory bud

4
Q

The respiratory bud is the origin of?

A

Respiratory tree

5
Q

What develop to form the tracheoesophageal septum?

A

Tracheoesophageal folds

6
Q

What do the tracheoesophageal folds cause to happen?

A

Splits the foregut into ventral and dorsal portions

  • ventral = laryngotracheal tube
  • dorsal = esophagus
7
Q

What creates the pulmonary epithelium and glands of the trachea, larynx and bronchi?

A

Endoderm of laryngotracheal groove

8
Q

What creates the cartilage, smooth muscle and CT of the trachea, larynx and bronchi?

A

Splanchnic lateral plate mesoderm

9
Q

What pharyngeal arches contribute to larynx and laryngeal muscle development?

A

4 and 6

10
Q

For the development of the larynx, mesenchyme produces?

A

Arytenoid swellings

11
Q

What do the arytenoid swellings do?

A

Convert the primordial glottis into a T-shaped laryngeal inlet

12
Q

After the arytenoid swellings for the T-shaped laryngeal inlet, what occurs to the laryngeal epithelium?

A

It proliferates and blocks the lumen of the larynx

13
Q

Recanalization of the larynx occurs by what week?

A

10th

14
Q

During recanalization of the larynx, what form that are bounded by mucous membranes?

A

Vocal and vestibular folds

15
Q

In a neonate, what is the epiglottis in contact with?

A

Soft palate

16
Q

How old is someone if their larynx is very high up?

A

Less than 2 years old

17
Q

Laryngeal descent occurs when?

A

Over first 2 years of life

18
Q

Laryngeal atresia

A

Failure of recanalization of the larynx

“CHAOS” - congenital high airway obstruction syndrome

19
Q

What are the symptoms of laryngeal atresia?

A

Lungs enlarged and filled with fluid
Airways dilated
Diaphragm flattened

20
Q

The trachea develops from?

A

Laryngotracheal tube

21
Q

Tracheal epithelium and glands form from?

A

Endoderm

22
Q

Tracheal cartilage, muscle and CT form from?

A

Splanchnic mesoderm

23
Q

Tracheoesophageal Fistula

A

Abnormal connection between the esophagus and trachea

24
Q

What causes a tracheoesophageal fistula

A

Foregut endoderm does not proliferate rapidly enough

25
Q

Most cases of tracheoesophageal fistula include what mechanical setup?

A

Esophageal atresia (blind esophagus)

26
Q

Symptoms of a tracheoesophageal fistula include?

A

Cannot swallow
Polyhydramnios - fluid cannot enter stomach for absorption
May reflux gastric contents into trachea and lungs

27
Q

What does the respiratory bud create?

A

Bifurcates into primary bronchial buds

28
Q

Primary bronchial buds grow into pericardioperitoneal canals and branch to form secondary and tertiary buds. What controls the branching pattern?

A

Splanchnic mesoderm

29
Q

Stages of lung development

A
  1. Pseudoglandular
  2. Canalicular
  3. Terminal sac
  4. Alveolar
30
Q

Pseudoglandular stage lung development

A

Weeks 5-17

All elements formed except for elements involved in gas exchange

31
Q

Can a fetus survive if born during pseudglandular stage (5-17 weeks)?

A

NO

32
Q

Canalicular stage of lung development

A

Weeks 16-25

Vascularization, respiratory bronchioles and primitive alveoli form

33
Q

Can a fetus survive if born during canalicular stage (16-25 weeks)?

A

Maybe

34
Q

Terminal sac stage of lung development

A

Weeks 24-birth

Type 1 and 2 alveolar cells present and gas exchange can occur!

35
Q

Can a fetus survive if born during terminal sac stage (24weeks +)?

A

Yes

36
Q

Alveolar stage of lung development

A

32 weeks - 8 years

Alveoli increase in number

37
Q

When do most mature alveoli develop?

A

Postnatally

38
Q

Lung growth involves an increase in?

A

NUMBER of bronchioles and alveoli

39
Q

Fetal breathing movements

A

Intermittent pattern that conditions respiratory muscles and fills lungs with amniotic fluid for their development

40
Q

At birth, the lungs require rapid replacement of the intra-alveolar fluid with air. How can this occur?

A
  • vaginal delivery pushes fluid out mouth and nose
  • arteries, veins, lymphatics
  • mechanically
41
Q

Pulmonary agenesis is the failure of ____ to split into right and left bronchial buds

A

Respiratory buds

42
Q

Can pulmonary agenesis be unilateral?

A

Yes

43
Q

Pulmonary hypoplasia

A

Due to restriction of fetal thorax due to uterine pressure and stunts their growth

44
Q

What condition can dramatically increase the risk of pulmonary hypoplasia?

A

Oligohydramnios

45
Q

Respiratory distress syndrome

A

Type 2 alveolar cells altered and cannot make surfactant!!

46
Q

When will you notice respiratory distress syndrome?

A

Shortly after birth

47
Q

What do the alveoli contain instead of surfactant with respiratory distress syndrome?

A

Glassy membrane fluid

48
Q

Signs of respiratory distress syndrome?

A

Rapid, labored breathing right after birth

- grunting, cyanosis, nasal flaring