Embryo respiratory system

Question 1

Lower respiratory tract includes

Answer 1

larynx, trachea, bronchi, lungs

Question 2

First respiratory formation

Answer 2

laryngotracheal groove

Question 3

Laryngotracheal groove arises from…

Answer 3

4th-6th pharyngeal arches

Question 4

LRT structures are made from which germ layer(s)?

Answer 4

from splanchnic mesoderm and endoderm

Question 5

Splanchnic mesoderm in the LRT gives rise to…

Answer 5

cartilage, smooth muscle, connective tissue

Question 6

Endoderm in the LRT gives rise to the..

Answer 6

epithelium, glands of larynx, trachea, bronchi, lungs

Question 7

LT diverticulum

Answer 7

as lungs elongate, it separates trachea and lungs

Question 8

TE septum

Answer 8

TE folds fuse to separate trachea and esophagus

Question 9

TE fistula

Answer 9

incorrect separation of trachea and esophagus- can result in esophageal atresia (blind ending)

most likely due to incomplete fusion of TE folds

Question 10

maturation of lungs (4 phases)

Answer 10

1. pseudoglandular
2. canalicular
3. terminal sac period
4. alveolar

Question 11

pseudoglandular period (5-17 weeks)

Answer 11

thick tissue between respiratory epithelium and capillaries

survival not possible

Question 12

canalicular period (16-26 weeks)

Answer 12

survival is possible but unlikely

Question 13

terminal sac period (24 weeks- birth)

Answer 13

surfactant is produced- good prognosis for survival

terminal branches of bronchi come in close contact with alveoli/blood vessles

Question 14

Alveolar period (birth - 8 years)

Answer 14

mature alveoli develop and multiply during this period

Question 15

surfactant produced by…

Answer 15

type 2 pneumocytes

Question 16

2 things that surfactant does in the lungs:

Answer 16

1. reduces surface tension at air-blood barrier to facilitate gas exchange
2. prevents the collapse of alveoli

Question 17

if born prior to 24-26 weeks will suffer from this disease:

Answer 17

respiratory distress syndrome

• inadequate surfactant
• insufficient alveolar surface area
• inadequate vasculature

can be treated with prenatal steroids to produce more surfactant asap

Question 18

differences in chest xray of infant and older child

Answer 18

infant- more white (dense) bc still some fluid left in lungs and fewer alveoli

Question 19

for normal lung development, in utero you need:

Answer 19

1. adequate space for lung development
2. fetal breathing movements to condition muscles
3. adequate amniotic volume (to protect the space for lung development- to protect muscle of uterus from clamping down on fetus)