Respiratory System and Body Cavity

Question 1

How many body cavities are created after embryonic folding?

Answer 1

1

Question 2

Where does the endodermal gut tube form?

Answer 2

In the centre (surrounded by visceral mesoderm)

Question 3

What is the lining of the respiratory tube?

Answer 3

Derivative of endoderm

Question 4

After how many does is the gut tube formed?

Answer 4

26

Question 5

What is the gut tube in communication with?

Answer 5

Cavity of respiratory diverticulum

Question 6

How does the gut tube and respiratory diverticulum separate?

Answer 6

There are pinch points at the junction between respiratory and oesophags which fuse and separate

Question 7

What are the swellings called?

Answer 7

Laryngeal swellings

Question 8

What does the foregut get split into?

Answer 8

Trachea and oesophagus

Question 9

As the bronchial tree grows, what does it carry with it?

Answer 9

Layer of mesoderm

Question 10

What is the lining of the bronchial tree?

Answer 10

Endoderm

Question 11

How many lobes does the right lung bud have?

Answer 11

3

Question 12

How many lobes does the left lung bud have?

Answer 12

2

Question 13

What is a fistula?

Answer 13

Abnormal communication between 2 spaces

Question 14

What is a blind end?

Answer 14

When there is no connection to the trachea (oesophageal atresia)

Question 15

Describe the maturation of lungs in the embryonic period (26 days - 6 weeks)

Answer 15

Respiratory diverticulum forms and initial segments arise

Question 16

Describe the maturation of lungs in the pseudoglandular period (6 - 16 weeks)

Answer 16

14 generations of branching occurs and terminal bronchioles arise

Question 17

Describe the maturation of lungs in the canalicular stage (16 - 28 weeks)

Answer 17

Terminal bronchioles give rise to 2-3 respiratory bronchioles which branch into 3-6 alveolar bronchioles

Question 18

Describe the maturation of lungs in the saccular stage (28 - 36 weeks)

Answer 18

Terminal sacs are formed and capillaries establish close contact with alveoli

Question 19

What are the airways lined with?

Answer 19

Endodermal lining (tall columnar cells)

Question 20

As alveoli develop, the cells lining the respiratory cells differentiate into what and why?

Answer 20

Squamous cells to minimise distance for oxygen and CO2 to diffuse across

Question 21

What cells form the blood-air barrier?

Answer 21

Squamous cells (type 1) and some cuboidal cells (type 2)

Question 22

What do type 2 cells do?

Answer 22

Produce surfactant which refuces surface tension

Question 23

Where does the septum transversum initially start off?

Answer 23

Very head end (cranial) of embryo

Question 24

What is located cranially to the heart tube?

Answer 24

Solid wedge of mesoderm

Question 25

What separates the thorax and abdomen?

Answer 25

Septum transversum (but does not reach posterior body wall)

Question 26

What are pericardio peritoneal canals?

Answer 26

Connecting space around the heart to the space around the peritoneal

Question 27

As the septum transversum migrates towards thorax, what does it take with it?

Answer 27

Phrenic nerve (C3,4,5)

Question 28

What organ forms in the septum transversum?

Answer 28

Liver

Question 29

How do the pericardio peritoneal canals close?

Answer 29

Outgrowths from posterior body wall (pleuroperitoneal fold) grows medially and anteriorly before fusing with septum transversum and mesoderm

Question 30

Where does the musculature for the diaphragm come from?

Answer 30

Septum transversum (innervated by phrenic nerve); ingrowth of body wall (local innervation)

Question 31

What is a hernia?

Answer 31

Something that buldges from one place into another

Question 32

What membrane is more likely to obtain a congenital diaphragmatic hernia?

Answer 32

Left pleuroperitoneal membrane (complete loss or thin membrane)

Question 33

What part of the thorax develops with the lungs?

Answer 33

Left and right pleural cavity

Question 34

What do the left and right pleural cavities contribute?

Answer 34

Cartilge and muscle to the lungs; covering layer of pleura

Question 35

What name is given to the growth that divides the body cavity into the heart (anterior) and lungs (posterior)

Answer 35

Transverse growth

Question 36

Describe what happens when the pleuroperitoneal folds migrate anteriorly

Answer 36

They pull a margin of the pleura cavirt posteriorly to surround the lungs