QUIZ 4

Question 1

What occurs during GA week 1?

Answer 1

blastocyst implantation

Question 2

What occurs during GA week 2?

Answer 2

blastocyst organizes into inner cell mass, which creates bilaminar disc

Question 3

What occurs during GA week 3?

Answer 3

bilaminar disc under goes gastrulation –> forms trilaminar disc

Question 4

What occurs during GA week 4?

Answer 4

later body and cephalocaudal folding; neurulation

Question 5

What are the 3 germ layers after gastrulation occurs?

Answer 5

1) ectoderm
2) mesoderm
3) endoderm

Question 6

Where is the trilaminar disc located?

Answer 6

B/W amniotic cavity and yolk sac

Question 7

What occurs to the trilaminar embryo at GA 18 days?

Answer 7

1) neuralation
2) lateral body folding
3) cephalocaudal (head and tail) folding

Question 8

Name steps of fetal heart development

Answer 8

1) single heart tube formation
2) single heart tube convolution
3) fetal heart septation
4) septation and spiraling of truncus arteriosus into great vessels

Question 9

What occurs during lateral body fusing?

Answer 9

two endocardial heart tubes fuse

Question 10

What occurs during cephalocaudal folding?

Answer 10

developing heart positioned in thoracic region

Question 11

Which parts of the single heart tube convolute to become the aorta and pulmonary artery?

Answer 11

1) aortic arches

2) bulbus cordis/truncus arteriorosus

Question 12

Which parts of the single heart tube become vena cava?

Answer 12

primitive veins in sinal horns

Question 13

What will the primitive ventricles become?

Answer 13

4 chambers of the heart

Question 14

When does septation occur?

Answer 14

by GA 37 days

Question 15

What occurs during septation?

Answer 15

establishment of 4 chambers of heart

Question 16

What does septation require?

Answer 16

endocardial cushions

Question 17

What does the endocardial cushion become?

Answer 17

1) mitral valve
2) triscuspid valve
3) lower atrial wall
4) upper ventricular wall

Question 18

Name 3 atrial septal defects (ASDs)

Answer 18

1) foramen ovale (ostium secundum) defect = most common
2) low ASD (ostium primum)
3) upper ASD (sinus venosus)

Question 19

Name 2 ventricular septal defects (VSDs)

Answer 19

1) membranous VSD = most common

2) muscular/infundicular VSD

Question 20

Name 2 atrioventricular canal defects (AVSDs)

Answer 20

1) complete AVSD

2) partial AVSD

Question 21

What defect is highly associated w/ complete AVSD?

Answer 21

trisomy 21

Question 22

What is the outcome of spiraling of the truncus arteriosus?

Answer 22

1) aorta aligned w/ L ventricle

2) pulmonary artery alined w/ R ventricle

Question 23

What are the 4 defects that contribute to tetralogy of Fallot (TOF)?

Answer 23

1) VSD
2) obstructed R ventricular outflow
3) aorta that overrides VSD
4) R ventricular hypertrophy

Question 24

Summarize TOF

Answer 24

unequal septation of truncus arteriosus –> large aorta, small pulmonary artery, high-lying VSD

Question 25

Describe transposition of the great arteries (TGA)

Answer 25

truncus arteriosus does not spiral --> aorta off R ventricle; pulmonary artery off L ventricle --> blood never gets oxygenated

Question 26

Describes persistent truncus arteriosus

Answer 26

truncus arteriosus does not septate --> single great artery that receives blood from both ventricles

Question 27

List the steps of pulmonary development

Answer 27

1) pseudoglandular period: formation of larynx and trachea 2) canalicular period: formation of bronchi and bronchioles 3) terminal sac period: formation of lungs* 4) alveolar period: formation of true alveoli

Question 28

From which tube are the larynx and trachea derived?

Answer 28

endoderm of gut tube

Question 29

How does trachoesophageal fistual/atresia develop?

Answer 29

incomplete separation and fusion of trachea and foregut

Question 30

When does agenesis of the lung occur?

Answer 30

failure of larynx to divide into bronchial buds

Question 31

What are 2 defects that can occur during the canicular phase?

Answer 31

1) bronchogenic cysts 2) pulmonary paranchymal cysts 3) cystic adenomatoid malformation (C-CAM) = most common 4) congenital lobar emphysema

Question 32

What occurs during the terminal sac period?*

Answer 32

1) terminal sacs form (capable of gas exchange) 2) number of capillaries increase 3) capillaries approach respiratory epithelium 4) epithelium becomes squamous cells

Question 33

How do steroid growth factors affect the terminal sac period?

Answer 33

Stimulate...: 1) bronchial divisions and vasculature 2) epithelium and connective tissue development

Question 34

What 4 structures form the diaphragm?

Answer 34

1) lateral body wall mesoderm 2) septum transversum 3) dorsal mesentery of esophagus 4) pleuroperitoneal folds

Question 35

type 1 alveolar epithelial cells

Answer 35

- make up squamous epithelium of early alveolar period of terminal sac period - permit gas exchange @ 25-26 weeks

Question 36

type 2 alveolar epithelial cells

Answer 36

develop and produce surfactant

Question 37

When is the alveolar period?

Answer 37

28 weeks GA to early childhood

Question 38

What occurs during the alveolar period?*

Answer 38

1) formation of true alveoli 2) fetal breathing movements occur 3) lungs making fluid

Question 39

Why may there be an absence of fetal breathing movements?

Answer 39

1) neurologic problems 2) polyhydramnios 3) oligohydramnios

Question 40

What can result from the absence of fetal breathing movements?

Answer 40

pulmonary hypoplasia: reduced number of bronchioles, terminal bronchioles, alveoli, and arterioles

Question 41

lung disease of prematurity

Answer 41

AKA respiratory distress syndrome AKA bronchopulmonary dysplasia - absence of alveoli and underdeveloped terminal sacs - thick, cuboidal epithelium - wide area b/w air-spaces and capillaries - surfactant deficiency d/t immature type II pneumocytes - arrested alveolar development --> large, underdeveloped alveoli --> less capable of gas exchange - reactive bronchi and bronchiole smooth muscle --> obstruction - inflammation and pulmonary edema - interstitial fibrosis w/ cystic changes - chronic hypoxemia --> pulmonary HTN

Question 42

Why is meconium irritating to bronchial and alveolar tissue?

Answer 42

b/c it is lipid and protein rich

Question 43

What occurs if meconium is inhaled during the birthing process?

Answer 43

- inflammatory broncho-constriction - chemical pneumonitis - inactivates surfactant

Question 44

What causes diaphragmatic hernia?

Answer 44

incomplete fusion of developing diaphragm tissues --> allows herniation of GI structures into thoracic cavity

Question 45

What is the effect of diaphragmatic hernia?

Answer 45

no space for lung to develop = leading cause of lung hypoplasia