Development of Respiratory System

Question 1

What develops in the ectoderm?

Answer 1

Neural groove

Question 2

What are the tips of the neural groove called?

Answer 2

Neural crest

Question 3

What happens when the neural groove is developing?

Answer 3

The lateral plate mesoderm will divide into the parietal and visceral mesoderm which becomes the serious membranes

Question 4

What does the parietal layer form?

Answer 4

Body walls

Question 5

What does the visceral layer form?

Answer 5

Surround the organs

Question 6

What does the parietal layer do in relation to the ectoderm?

Answer 6

Starts to merge

Question 7

What two things occur when the parietal layer merges with the ectoderm?

Answer 7

Primitive yolk sac becomes pinched and this will develop into the digestive tract. The visceral layer of the lateral plate mesoderm will envelope the future gut tube

The leading edge of the ectoderm and the parietal layer of the lateral plate mesoderm will move antero-medially

Question 8

What does the eventual connection between the gut tube and secondary yolk form?

Answer 8

Vitelline duct

Question 9

What structures are present once the parietal layer fully fuses with the lateral plate mesoderm?

Answer 9

A cavity (coelom) which will become the thoracic, abdominal and pelvic cavity

A body wall made out of a surface ectoderm and parietal layer of lateral plate mesoderm deep to it

The gut tube, suspended by visceral layer of lateral plate mesoderm

Question 10

Pericardio-peritoneal canals

Answer 10

Lecture

Question 11

What happens when the embryo is about 4 weeks old?

Answer 11

In the cervical portion of the gut tube, in the ventral midline, the respiratory diverticulum starts to appear

The respiratory diverticulum expands ventrally and towards the chest, in front of the gut tube

Tracheo-oesophageal ridged grow towards each other and separate the RD from the gut tube

The diverticulum bifurcates into two branches

Terminal ends of these dilations are called lung buds

Question 12

When do the pharyngeal arches begin to develop?

Answer 12

Week 4-5

Question 13

What separates the pharyngeal arches?

Answer 13

Pharyngeal clefts

Question 14

How many pharyngeal arches are there?

Answer 14

5

Question 15

What does each pharyngeal arch have?

Answer 15

Cartilaginous element

An aortic arch

Cranial nerve

Question 16

Where is the gut tube and RD still connected?

Answer 16

Laryngeal orifice

Question 17

What will the upper end of the respiratory diverticulum form?

Answer 17

Larynx

Question 18

What does the middle section of respiratory diverticulum form?

Answer 18

Trachea

Question 19

What will the lower end of the respiratory diverticulum form?

Answer 19

Tertiary bronchi

Bronchioles

Alveoli

Question 20

What does the respiratory diverticulum develop from?

Answer 20

Endoderm and surrounded by the visceral layer of the lateral plate mesoderm

Question 21

What is the only part of the respiratory system that is derived from the endoderm?

Answer 21

Epithelium

Question 22

What structures of the respiratory system are derived from mesoderm?

Answer 22

Cartilage

Trachealis muscle

Question 23

What does the bronchial tree do when it grows?

Answer 23

Pushes the visceral layer of lateral plate mesoderm

Question 24

What stages do the lungs develop in?

Answer 24

Pseudoglandular

Canalicular

Terminal saccular

Alveolar

Question 25

What stages in lung development are incompatible with gas exchange?

Answer 25

Pseudoglandular Canalicular

Question 26

What are the four sources of diaphragm origin?

Answer 26

Pleura-peritoneal folds Septum transversum Mesentery of the oesophagus Muscular in-growth from the body wall

Question 27

What forms the central tendon of the diaphragm?

Answer 27

Septum transversum

Question 28

What does the septum transversum contain?

Answer 28

Myoblasts from somites C3,4,5

Question 29

What does failure in normal development of any sources of the diaphragm lead to?

Answer 29

Diaphragmatic hernia

Question 30

What occurs 90% of the time in babies with congenital anomalies of the trachea?

Answer 30

Tracheo-oesophageal fistula Communication between the trachea and oesophagus Accompanied by oesophageal atresia

Question 31

What happens if the trachea-oesophageal fistula allows passage from the oesophagus into the trachea?

Answer 31

When feeding, milk will enter and cause chocking possible development of pneumonitis and pneumonia Also possible of retrograde passage of gastric acid

Question 32

What is oesophageal atresia?

Answer 32

When the two ends of the oesophagus don't meet, stopping the transport of food

Question 33

What is a diaphragmatic hernia?

Answer 33

When the diaphragm fails to close during prenatal development, and the contents from the abdomen (stomach, intestines and/or liver) migrate into the chest through this hole

Question 34

What is respiraotyr distress syndrome?

Answer 34

Insufficient surfactant results in the collapse of the alveolar wall during expiration Deficiency of surfactant secretion results in respiratory distress syndrome

Question 35

How we treat respiratory distress syndrome?

Answer 35

Glucocorticoids

Question 36

At what level does the trachea-oesophageal ridge form on the gut tube?

Answer 36

Foregut

Question 37

What are the different pharyngeal arches?

Answer 37

1st 2nd 3rd 4th 6th

Question 38

What are the two swellings found on the anterior walls of the pharyngeal arches?

Answer 38

Laryngeal swellings Epiglottal swelling

Question 39

Where does septum transversum grow from?

Answer 39

Anteriorly

Question 40

Where does the pleuroperitoneal fold grow from?

Answer 40

Posteriorly

Question 41

What is a fistula?

Answer 41

When part of the oesophagus either attaches or opens up into the trachea

Question 42

What are the different types of hernias?

Answer 42

Bochdalek hernia Morgagni hernia Central hernia

Question 43

What causes a Bochdalex hernia?

Answer 43

Posterolateral defect in fusion of pleura-peritoneal folds

Question 44

What causes a Morgagni hernia?

Answer 44

Failure in the development in septum transversum

Question 45

What causes a central hernia?

Answer 45

Defect on central tendon

Question 46

What hernia is most common?

Answer 46

Bochdalek hernia