Embryology

Question 1

Parts of the upper respiratory tract

Answer 1

Nasal cavity
Pharynx
Larynx

Question 2

Parts of the lower respiratory tract

Answer 2

Trachea
Bronchi
Lungs (bronchioles to alveoli)

Question 3

Which portions of the lower respiratory tract can actually take part in gas exchange

Answer 3

Respiratory bronchioles
Alveolar duct
Alveolus

Question 4

Gas exchange (oxygen and CO2) are exchanged between blood and air in the…

Answer 4

alveoli

Question 5

In order for gas exchange to occur, the alveoli must be….

Answer 5

really thin

Question 6

Lipid layer that lines the lumens of alveoli; keeps surface tension low to they don’t collapse (atelectasis)

Answer 6

surfactant

Question 7

Collapse of alveoli; can be caused by loss/absence of surfactant; causes respiratory distress

Answer 7

atelectasis

Question 8

From which germ layer does the respiratory system arise from (ecto-, endo- or meso-)

Answer 8

Endoderm

Question 9

The lower respiratory tract arises from what part of the early GI tract?

Answer 9

anterior diverticulum (specifically, pharynx/upper esophagus)

Question 10

At what week does the lower respiratory tract arise from the anterior diverticulum?

Answer 10

Week 4

Question 11

The lower respiratory tract develops in what direction (caudal vs. cranial)?

Answer 11

Cranial to caudal (alveoli are last to form)

Question 12

How many “generations” of branching of the airway are there?

Answer 12

23

Question 13

Which structures of the respiratory system are the last to form?

Answer 13

Alveoli

Question 14

There is respiratory function in utero because the fetus makes respiratory movements (True or False)

Answer 14

False; fetus does “breathe” amniotic fluid, but the movement is necessary for normal lung development (but no gas exchange occurs)

Question 15

Gas exchange for the fetus occurs in the…

Answer 15

placenta

Question 16

vascular structure formed by the embryo; where gas exchange occurs for the fetus; no mixing of fetal and maternal blood occurs

Answer 16

Placenta

Question 17

The placenta allows for gas exchange via the mixing of fetal and maternal blood supplies (True or False)

Answer 17

False

Question 18

What properties of the alveoli help promote gas exchange

Answer 18

Thin walls

Surfactant

Question 19

How many weeks constitutes a full-term fetus?

Answer 19

38 weeks

Question 20

What week do primitive, thick-walled alveoli begin to develop?

Answer 20

Week 22

Question 21

What week does surfactant begin to be produced?

Answer 21

Week 24

Question 22

Premature infants with underdeveloped lungs can be given artificial surfactant to aid in respiratory function (True or False)

Answer 22

True

Question 23

What defines a “premature” baby?

Answer 23

at least 3 weeks before due date

Question 24

congenital anomaly; arises early (4-7 weeks); an abnormal opening of the esophagus into the trachea; can present with polyhydramnios (excessive amniotic fluid), choking, coughing, cyanosis and vomiting

Answer 24

Tracheoesophageal fistula

Question 25

Most common form of tracheoesophageal fistulas

Answer 25

Type C (proximal esophagus terminates, and distal is connected with trachea)

Question 26

Possible symptoms of tracheoesophageal fistulas (in utero and after birth)

Answer 26

in utero: polyhydramnios (excess amniotic fluid) | after birth: choking, coughing, cyanosis and vomiting

Question 27

congenital anomaly; hole in posterolateral diaphragm, usually on left; abdominal organs can herniate into thorax, especially the small intestine; can crowd the lungs and heart, resulting in malformed lungs (hypoplasia) and pulmonary hypertension

Answer 27

Congenital Diaphragmatic Hernia (CDH)

Question 28

Potential complications with congential diaphragmatic hernia

Answer 28

Pulmonary hypoplasia Pulmonary hypertension Life threatening breathing difficulties

Question 29

Fetal cardiopulmonary physiology

Answer 29

Relative hypoxic environment (compared to mom) Fetal shunts Fetal lungs produce fluid Erythropoiesis shifts from liver to bone marrow

Question 30

Steps for fetal cardiopulmonary transition prior to the onset of labor

Answer 30

Lung maturity (surfactant) Absorb lung fluid Inc. blood oxygen content Loss of placental circulation

Question 31

Fetal shunts

Answer 31

``` Ductus venosus (bypass liver) Ductus arteriosus (bypass lungs) Foramen ovale (RA to LA) ```

Question 32

Pulmonary circulation oxygen saturation in fetuses

Answer 32

~55%

Question 33

When does cortisol peak during gestation

Answer 33

30-36 weeks

Question 34

What does the cortisol peak do during gestation?

Answer 34

Influences angiogenesis and matures parenchyma; enhances clearance of lung fluid and production of surfactant

Question 35

Secretion of fetal lung fluid begins at what week of gestation?

Answer 35

~6th week

Question 36

How does the fetal lung secret fluid?

Answer 36

Produced by active secretion of chloride, creating an osmotic gradient

Question 37

Why does preterm labor and c-section delivery result in fluid retention in lungs?

Answer 37

Fetal lung clearance begins several days before labor. Failure of normal absorption results in respiratory distress

Question 38

Fetal lung fluid is cleared and drained via ___________ circulation

Answer 38

pulmonary

Question 39

Ion transporter involved in fetal lung fluid reabsorption shortly before labor

Answer 39

ENaC (moves Na in, which also draws Cl and water in as well)

Question 40

How might the presence of fetal lung fluid help the first breath?

Answer 40

By establishing a lower opening pressure

Question 41

When does the ductus venosus close?

Answer 41

1 week after birth

Question 42

When does the ductus arteriosus close?

Answer 42

4-8 weeks after birth

Question 43

When does the foramen ovale close?

Answer 43

months to years after birth

Question 44

How long does it take for an average baby to reach 90% oxygen saturation after birth (in minutes)

Answer 44

~5-6 minutes

Question 45

Why might it be detrimental to clamp the umbilical cord before the baby has the chance to establish ventilation?

Answer 45

Causes dec. venous return Cardiac output dec. Systemic BP increases to compensate Low pulmonary blood flow

Question 46

congenital anomaly; most common developmental lesion of the respiratory tract; previously known as congenital cystic adenomatoid malformation

Answer 46

Congenital Pulmonary Airway Malformation (CPAM) * previously known as CCAM

Question 47

When does CPAM often diagnosed in the US?

Answer 47

weeks 18-22 gestation

Question 48

Blind pouch/tube

Answer 48

diverticulum