Respiratory system embryo

Question 1

The laryngotracheal groove appears where?

Answer 1

In the floor of the caudal pharynx

Question 2

Where does the lung bud (respiratory diverticulum) come from?

Answer 2

It comes from an endodermal outgrowth from the foregut off the growing laryngotracheal groove

Question 3

______ _____ develops, separating the lung bud (ventrally) from the foregut (distally)

Answer 3

Tracheoesophageal septum

Question 4

The respiratory diverticulum retains a connection with the pharynx at the _____ _____ _____.

Answer 4

Primordial laryngeal inlet

Question 5

What causes esophageal atresia?

Answer 5

A posteriorly deviating septum

Question 6

If a tracheoesophogeal fistula occurs and you have acid reflux, where does the acid go?

Answer 6

Instead of coming up the esophagus and to the mouth, the esophagus is connected to the trachea so the acid would go into your windpipe and lungs

Question 7

In lung buds, what does the endoderm give rise to?

Answer 7

epithelial lining and glands of airways

Question 8

In lung buds what does the splanchnic mesoderm give rise to?

Answer 8

smooth muscle and CT of airways

Question 9

The esophagus develops as a portion of the _____ immediately caudal to the ______.

Answer 9

foregut

pharynx

Question 10

Laryngeal cartilages and musclulature arise from the pharyngeal arch pairs ____ and _____.

Answer 10

4

6

Question 11

Where does the epiglottis form from?

Answer 11

The mesenchyme of the hypopharyngeal eminence

Question 12

Laryngeal muscles arising from the 4th arch are innervated by what nerve?

Answer 12

Superior laryngeal nerve

Question 13

Laryngeal muscles arising from the 6th arch are innervated by what nerve?

Answer 13

Recurrent laryngeal nerve

Question 14

The lung bud divides to form two ____ ____ ____.

Answer 14

primary bronchial buds

Question 15

What do primary bronchial buds give rise to?

Answer 15

Primary bronchi

Question 16

When do the primary bronchial buds form?

Answer 16

Day 28

Question 17

What gives rise to the visceral pleura of the lungs?

Answer 17

Splanchnic mesoderm

Question 18

Somatic mesoderm lining the thoracic body wall gives rise to what?

Answer 18

Parietal pleura

Question 19

The pericardioperitoneal canal becomes what?

Answer 19

The pleural canal

Question 20

On what day do secondary bronchial buds form?

Answer 20

Day 30

Question 21

Secondary bronchial buds divide to form what?

Answer 21

Tertiary bronchial buds

Question 22

Which side has more bronchial buds?

Answer 22

Right side

Question 23

Trace the path of air as it goes into the lungs.

Answer 23

Trachea  primary bronchi  secondary (lobar) bronchi  tertiary (segmental) bronchi  bronchioles  terminal bronchioles  respiratory bronchioles  alveolar ducts  terminal sacs (primitive alveoli)

Question 24

Where is the site of main gas exchange?

Answer 24

Alveoli

Question 25

When does the pseudo glandular stage occur?

Answer 25

6-16 weeks

Question 26

When does the canalicular stage occur?

Answer 26

16-26 weeks

Question 27

When does the terminal sac stage occur?

Answer 27

26 weeks- birth

Question 28

When does the alveolar stage occur?

Answer 28

32 weeks-8 years old

Question 29

Will a fetus survive if it is born during the pseudo glandular stage?

Answer 29

No- gas exchange cannot occur because it hasn’t yet developed

Question 30

When does respiration become possible?

Answer 30

At the end of the canalicular stage- infants born here probably won’t survive

Question 31

What has happened at the end of the canalicular stage?

Answer 31

Each terminal bronchiole has split into 2 respiratory bronchioles, which have developed primitive alveolar ducts- some lead into terminal sacs, which are primitive alveoli

Question 32

Through which cells do gasses diffuse?

Answer 32

Type 1 alveolar cells

Question 33

During the terminal sac stage, more terminal sacs (primitive alveoli) develop and are hugged by capillaries, establishing what?

Answer 33

A blood-air barrier

Question 34

What do type II alveolar cells do?

Answer 34

Produce, store, and secrete pulmonary surfactant (test question!)

Question 35

At what point does a baby have enough pulmonary surfactant to survive?

Answer 35

26-28 weeks

Question 36

What is pulmonary surfactant?

Answer 36

It lines the inner wall of the alveolus and reduces surface tension at the air-alveolar interface to prevent the collapsing of the alveolus upon exhaling. (Test Question!!)

Question 37

If babies are born at 24-26 weeks, they may survive, but may suffer from what due to insufficient surfactant?

Answer 37

Respiratory distress syndrome

Question 38

___% of mature alveoli develop postnatally and will continue to develop until _ yeas of age.

Answer 38

95

8

Question 39

When do alveoli become fully functional?

Answer 39

32 weeks