Embryology

Question 1

How does fetal lung development begin

Answer 1

ventral outpouching of the endodermal foregut called the respiratory (laryngotracheal) diverticulum (lung bud) –> day 22

Question 2

The proximal end of the respiratory diverticulum forms the…

Answer 2

Larynx and trachea

Question 3

The lung is comprised of what types of tissue

Answer 3

endoderm and mesoderm

Question 4

The endoderm of the respiratory diverticulum gives rise to…

Answer 4

mucosal lining of the bronchi and to the epithelial cells of the alveoli

Question 5

Mesoderm in the lung forms…

Answer 5

muscle and cartilage supporting the bronchi and the visceral pleura covering the lung

Question 6

tracheoesophageal septum forms from…

Answer 6

fusing of the two tracheoesophageal ridges (folds)

Question 7

dorsal foregut becomes…

ventral foregut becomes…

Answer 7

esophagus

trachea and lung buds

Question 8

Tracheo-esophageal fistula (TEF) results from…

Answer 8

incomplete fusion of the tracheoesophageal folds that results in a failure of the foregut to separate completely into trachea and esophagus.

Question 9

Trachea develops from …

Answer 9

proximal part of the respiratory diverticulum

Question 10

The cartilage, connective tissue, and muscles of the trachea are derived from…

Answer 10

splanchnic mesenchyme surrounding the laryngotracheal tube.

Question 11

Number of lung lobes in each for developing embryo

Answer 11

3 in right, 2 in left

Question 12

When is the limited age of viability and why?

Answer 12

22-23 weeks gestation. Respiration is possible only after the blood-air barrier is esblished and the gas exchange can be performed

Question 13

complex mixture of phospholipids and proteins in maturing alveoli

Answer 13

Pulmonary surfactant (secreted by alveolar type II cells)

Question 14

The respiratory distress syndrome of premature infants is caused by

Answer 14

inadequate production of surfactant

Question 15

Potter sequence

Answer 15

a spectrum of abnormalities . These include deformed limbs; wrinkly, dry skin; and an abnormal facies (in this context, facies means “facial appearance”) consisting of wide-set eyes with infraorbital skin creases, beak nose, recessed chin, and low-set ears.

Question 16

The intraembryonic coelom is partitioned by

Answer 16

A pair of pleuropericardialmembranes

A pair of pleuroperitoneal membranes

Question 17

When the intraembryonic coelom forms, the lateral mesoderm divides into:

Answer 17

somatic (parietal) and splanchnic (visceral) mesoderm

Question 18

Each pericardioperitoneal canal lies:

Answer 18

• lateral to the foregut(future esophagus)
• dorsal to septum transversum(part of the future diaphragm).

Question 19

4 embryonic sources of diaphragm

Answer 19

Question 20

central tendon of the diaphragm is made of what tissue

Answer 20

mesodermal mass in the cervical region of the embryo

Question 21

Fusing of what two tossues completes the partition between thoracic and abdominal cavities

Answer 21

dorsal mesentery of esophagus and septum transversum

Question 22

Congenital Diaphragmatic Hernia (CDH) is caused by what

Answer 22

failure of pleuroperitoneal foldsto develop or to fuse with other components of diaphragm (usually posterolateral on left side)

Question 23

Blood vessel formation begins during week … in the extraembryonic mesoderm of the yolk sac, connecting stalk and chorion.

Answer 23

3

Question 24

Primary embryonic arteries

Answer 24

paired dorsal aorta

intersegmental arteries between somites

aortic arch arteries

Question 25

Primary embryonic venous system

Answer 25

Cardinal venous system

Question 26

Placenta blood flow

Answer 26

Blood enters embryo through 1 umbilical vein and returns to mother through 2 umbilical arteries

Question 27

Circulation of yolk sac is primary through ...

Answer 27

Vitelline veins

Question 28

Caudally, the dorsal aortae fuse to form

Answer 28

Descending aorta

Question 29

From where do pharyngeal arch arteries arise?

Answer 29

aortic sac

Question 30

How are the aortic sac and dorsal aortae connected

Answer 30

aortic arches

Question 31

What is the function of umbilical arteries

Answer 31

Links dorsal aortae to capillaries of chorionic villi (develop in connecting stalk)

Question 32

Name gastrointesinal arteries

Answer 32

Celiac (caudal) Superior Inferior mesenteric (rostral) Form from vitalline, off of descending aorta

Question 33

What does the aortic sac later give rise to

Answer 33

Brachiocephalic artery and ascending aorta

Question 34

What does the third aortic arch become

Answer 34

Common carotid arteries Proximal internal carotid arteries (rest by doersal aorta)

Question 35

From what do external carotids form

Answer 35

They sprout from the internal carotids

Question 36

Left fourth aortic arch forms... Right fourth aortic arch forms...

Answer 36

Part of aortic arch Proximal right subclavian artery

Question 37

Left sixth aortic arch becomes Right sixth aortic arch becomes

Answer 37

Left pulmonary artery and ductus arteriosus Right pulmonary artery

Question 38

The recurrent laryngeal nerves hook around which aortic arches

Answer 38

sixth

Question 39

3 paired veins that drain into sinus venosus

Answer 39

vitelline veins (low oxygen, yolk sac) Umbilical veins (placenta, high oxygen) Common cardinal veins (low oxygen, embryonic body)

Question 40

What veins drain cranial portion of embryo

Answer 40

anterior cardinal veins

Question 41

Anterior cardinal veins join to form what? Function?

Answer 41

Left brachiocephalic vein, shunts blood from left to right AC vein

Question 42

What forms the superior vena cava

Answer 42

right anterior cardinal and right common cardinal veins

Question 43

Supracardinal veins form from

Answer 43

Posterior cardinal veins

Question 44

Azygous vein forms from

Answer 44

Right supracardinal vein

Question 45

Left supracardinal vein forms

Answer 45

Hemizygous vein Accessory hemizygous vein

Question 46

Function of ductus venosus

Answer 46

allows most of the blood from the placenta to bypass the liver (by flowing directly into IVC)

Question 47

Portal vein is derived from

Answer 47

vitelline veins

Question 48

Left umbilical vein becomes ...

Answer 48

Umbilical vein

Question 49

Where does the heart begin to develop

Answer 49

The cardiogenic region

Question 50

Angioblastic cords form from what tissue

Answer 50

Mesoderm

Question 51

angioblasticcords canalize (hollow out) to form

Answer 51

two parallel endocardial heart tubes

Question 52

Splanchnic mesoderm becomes... Somatic mesoderm becomes...

Answer 52

Visceral pericardium Parietal pericardium

Question 53

Flow of blood through primitive heart

Answer 53

Question 54

Dextrocardia cause

Answer 54

* Embryonic heart tube bends to the left instead of to the right * Heart is displaced to the right

Question 55

What is sinus venarum

Answer 55

Part of the developing atrium where the sinus venosus is incorporated into

Question 56

How do pulmonary veins form

Answer 56

During week 4, the primitive atrium sprouts a pulmonary vein that divides to produce a total of 4 pulmonary veins that grow toward the lungs where they anastomose with veins developing in the mesoderm around the bronchial buds.

Question 57

Four sets of partitions in developing heart seperate:

Answer 57

1) the atria from the ventricles 2) the right and left atria 3) the right and left ventricles 4) the pulmonary trunk and ascending aorta

Question 58

What is the atrioventricular canal

Answer 58

a large single passageway between the primitive atrium and the primitive ventricle

Question 59

Ebndocardial cusions do what?

Answer 59

Theendocardial cushions grow toward one another and fuse medially, dividing the AV canal into a right and left atrioventricaropenings.

Question 60

What is the foramen primum

Answer 60

opening between the septum primumand the endocardial cushions.

Question 61

Order of atrial spetation

Answer 61

1. Foramen primum 2. Septum primum 3. Foramen secundum 4. Septum secundum 5. Foramen Ovale 6. Fossa Ovalis

Question 62

What forms the partition between aorta and pulmonary trunk

Answer 62

aorticopulmonary septum

Question 63

The aorticopulmonary septum develops from what

Answer 63

Truncal ridges and bulbar ridges (neural crest cells)