Development

Question 1

What is the epithelial lining of the larynx, trachea, bronchi and lungs formed from?

Answer 1

Endoderm

Question 2

What is the cartilage, smooth muscle, elastic tissue, and fibrous CT of Larynx, trachea, bronchi and lungs formed from?

Answer 2

Splanchnic mesoderm

Question 3

What 2 main events occur in the embryonic phase (Wk 4-7)?

Answer 3

Lung primordium

Initial airway branching

Question 4

The respiratory diverticulum is an outgrowth of the __________.

Answer 4

Foregut

Question 5

The first branch is the primary _________ and 2nd set are the ________________.

Answer 5

Bronchi

Lobar bronchi

Question 6

What occurs during the pseudoglandular phase (wk6-16)?

Answer 6

Airway branching continues due to Epithelial-Mesenchymal interactions.

Question 7

What 2 events occur during the Canalicular Phase (Wk 16-26)?

Answer 7

1. Capillary density increases

2. Alveolar cells (pneumocytes) begin to differentiate

Question 8

What are the chances of survival for an infant born during the pseudoglandular phase?

Answer 8

Not high - depends on capillary extent/pulmonary circulation & differentiation of pneumocytes

Question 9

What occurs during the terminal sac phase? Wk 26-birth

Answer 9

Distal airways dilate forming primitive alveoli/terminal sacs

Question 10

What two things occur during the alveolar phase? (32wk - 8yrs)

Answer 10

1. Alveolar formation begins

2. Alveolar septum become thinner

Question 11

Alveolar formation begins by subdivision of terminal sacs - _________.

Answer 11

Septation

Question 12

Most alveoli form ____________.

Answer 12

After birth - proportional to body growth

Question 13

Formation of airways in the lung proceeds in what direction?

Answer 13

Proximal to distal

Centrifugally

Question 14

Are epithelial-mesenchymal interactions involved in lung formation?

Answer 14

Yes

Question 15

The prenatal lung contains what?

Answer 15

Amniotic fluid

Question 16

What happens if there is insufficient fluid production by the lung?

Answer 16

Hypoplastic lung

Question 17

What pulmonary, circulatory and neural changes allow breathing?

Answer 17

1. Fluid replaced by air
2. Cardiac shunts close
3. Pulmonary vessels fill
4. Neural breathing
5. Sympathetic activation (reduces secretion)

Question 18

Wet Lung

Answer 18

Problems with fluid removal - transient tachypnea (more common w/ C-Section)

Question 19

What are 2 characteristics of the new air/liquid interface w/i the alveoli?

Answer 19

1. Thin compliant wall

2. Subjected to surface tension

Question 20

What produces pulmonary surfactant and when does it begin?

Answer 20

1. Type 2 pneumocytes

2. End of canalicular pd - inc. at week 35

Question 21

What are the 3 fx of pulmonary surfactant?

Answer 21

1. Dec. surface tension
2. Stabilize alveolar surface
3. Dec. fluid transfer

Question 22

Without surfactant what would happen to alveoli in between breaths?

Answer 22

They’d collapse

Question 23

What is pulmonary surfactant made of?

Answer 23

1. Phospholipid (imp for reducing surface tension)
2. Protein
3. Antioxidant

Question 24

What are clinical signs of respiratory distress in a newborn?

Answer 24

1. Tachypnea (>60/min)
2. Flaring nostrils
3. Chest retractions
4. Expiratory grunt
5. Cyanotic
6. Tachycardic
7. Anxious

Question 25

Detecting presence of phosphatidylglycerol indicates what?

Answer 25

Lung maturity more accurately than L:S ratio

Question 26

What can you give to enhance fetal lung maturation?

Answer 26

1. Glucocorticoids to mom before delivery

2. Artificial surfactant to newborn