Embryology Of Trachea, Bronchi, Lungs

Question 1

Development of the trachea, bronchi and lungs

The lower respiratory organs i.e. _____,____,___,____ begin to form during the ______ week

Answer 1

larynx, trachea, bronchi and lungs

fourth

Question 2

The respiratory primordium appears as a ______ from the (ventral or Dorsal?) wall of the _____- the ______________

Answer 2

median outgrowth

Ventral

foregut

laryngotracheal groove

Question 3

• By the end of 4th week, the laryngotracheal groove has __ginated to form a _____-like structure called the ________
• This would _____ and is invested with ______ mesenchyme and its (proximal or distal?) end enlarges to form a ______-shaped _____

Answer 3

eva

pouch

respiratory diverticulum

elongate

splanchnic; distal

globular

respiratory bud

Question 4

Soon 2 longitudinal ridges separate the laryngotracheal groove from the foregut- the __________

• Subsequently the 2 ridges fuse to form the _______
• Dividing the foregut into a ventral part- __________ and a dorsal part (primordium of _________ and _______ )

Answer 4

tracheoesophageal ridges

tracheoesophageal septum

laryngotracheal tube

oropharynx and esophaus

Question 5

After formation of the tracheoesophageal septum , the laryngotracheal tube separates from the foregut and forms the;
➢ ______
➢The __________

Answer 5

Trachea

bronchial (lung) buds.

Question 6

Development of Trachea

• The endodermal lining of the laryngotracheal tube differentiates into the ______ and ____ of the trachea and the ______
• The cartilages, CT, and muscles of the trachea are derived from the __________________________________

Answer 6

epithelium and glands; pulmonary epithelium

splanchnic mesenchyme surrounding the laryngotracheal tube

Question 7

DEVELOPMENT OF THE BRONCHI
•The respiratory bud that developed at the (cranial or caudal ?) end of _______ during the 4th week divides into two outpouchings – _______

• These endodermal buds grow (medially or laterally?) into the ______ canals
• Together with the surrounding splanchnic mesenchyme, the bronchial buds differentiate into ____ and their ramifications in the lungs

Answer 7

Caudal

laryngotracheal tube

pry bronchial buds.

Laterally

pericardioperitoneal

bronchi

Question 8

pericardioperitoneal canals is the primordia of the _________

Answer 8

pleural cavities

Question 9

_____ week- each of the bud enlarge to form the main or principal bronchi.

•The main bronchi subdivides into ____ bronchi that divides into _____ bronchi around the ____ week.

Answer 9

5TH

lobar

segmental

7th

Question 10

Each segmental bronchus with its surrounding mass of mesenchyme is the primordium of a ________

Answer 10

bronchopulmonary segment

Question 11

By ___ weeks respiratory bronchioles have developed

Answer 11

24

Question 12

The lungs acquire a layer of _____ pleura from the splanchnic mesoderm and a layer of _____ pleura from the somatic mesoderm

•Space btw the two layers is ????

Answer 12

visceral

parietal

pleural cavity

Question 13

Maturation of the lungs is divided into five periods
•_______ period

• _________ period
• ________ period
• _______ period
• _________ period

Answer 13

Embryonic

Pseudoglandular

Canalicular

Terminal sac

Alveolar

Question 14

EMBRYONIC PERIOD of lung maturation

●It occurs between the ___-___ week of gestation.

•During this period the tracheobronchial bud divides to form the proximal airways to the level of the ___________

Answer 14

4th to 6th

segmental bronchi.

Question 15

PSEUDOGLANDULAR PERIOD of lung maturation

__-___WEEKS

• The ___ resembles an ______ during this period.
• Branching has continued to form ____ bronchioles.
• By the end of this period , all major elements of the lung have formed, except those involved with ______

Answer 15

6- 17

terminal bronchiole; exocrine gland

terminal

gas exchange.

Question 16

Presence of respiratory bronchioles or alveoli in PSEUDOGLANDULAR PERIOD of lung maturation

T/F

Answer 16

F

No respiratory bronchioles or alveoli are present.

Question 17

CANNALICULAR PERIOD of lung maturation

___-___WEEKS
• Each terminal bronchioles divides into two or more ________ that divides into __to__ ______ that end in ______ (primitive ____)

•The tissues become more ____ as _____ develop.

Answer 17

17-26

respiratory bronchioles

3 to 6

alveolar ducts.

terminal sacs

alveoli

vascular; capillaries

Question 18

TERMINAL SAC PERIOD of lung maturation

from _____ to _____
•Many more _____ (primitive alveoli) develops and their epithelium becomes very (thin or thick ?)
•Capillaries begin to ____ into ________
•The intimate contact between ______ and _______ cells establishes the ______.

Answer 18

24 weeks to birth

terminal sacs

Thin

bulge; these developing alveoli.

epithelial and endothelial

blood-air barrier

Question 19

blood-air barrier permits adequate gas exchange for survival of the foetus if it is born prematurely

T/F

Answer 19

T

Question 20

TERMINAL SAC PERIOD of lung maturation
•By ___ weeks, the terminal sacs are lined mainly by ____ epithelial cells of __dermal origin

➢Type I alveolar cells or pneumocytes- _______ function.
➢Type II alveolar cells — ___________ function

Answer 20

24

squamous

endo

gas exchange

which secrete pulmonary surfactant.

Question 21

Sufactant production begins in the ____ week and ___eases during the ____ weeks of pregnancy.

Answer 21

20th

Incr

last 2

Question 22

fetuses born prematurely at 24-26 wks after fertilization may survive intensive care but may suffer respiratory distress because of _____

•Survival has improved with the use of ___________

Answer 22

surfactant deficiency

antenatal corticosteroids

Question 23

ALVEOLAR PERIOD of lung maturation

______ PERIOD TO _____
•Structures analogous to alveoli are present at ____ weeks of gestation
•At the beginning of the alveolar period, each respiratory bronchiole terminates in a cluster of (thin or thick?) -walled terminal sacs.
•Characteristic mature alveoli do not form until _____

Answer 23

LATE FETAL; CHILDHOOD

32

Thin

after birth

Question 24

about 95% of alveoli develop prenatally

T/F

Answer 24

F

about 95% of alveoli develop postnatally

Question 25

TRACHEOESOPHAGEAL FISTULA
•It is an abnormal connection between the _____ and the ____.

•It occurs due to improper division of the ____ by the ____________

Answer 25

lower oesophagus

trachea

foregut

tracheoesophageal septum

Question 26

unilateral pulmonary agenesis is incompatible with life

T/F

Answer 26

F

It is

Question 27

Accessory lung-

(Common or uncommon?)

always located at the ___ of the ____

Answer 27

Uncommon

base

left lung