Exam 17 - Resp01 - Embryology Of The Respiratory System

Front 1

When is the embryonic phase?

Back 1

3-7 weeks

Front 2

The development of the upper respiratory system (mouth,nose, oral pharynx) and lower respiratory system (oral pharynx down) starts at day...-....

Back 2

24-26

Front 3

The respiratory system starts to develop with an inconspicuous ... that forms in the ventral midline at the lower end of the pharynx.

Back 3

laryngotracheal groove

Front 4

The laryngotracheal groove deepens and grows downward to form a pouch-like evagination, fully open to the foregut, forming a new tube (...) distinct from the foregut. Communications with the foregut is maintained via a longitudinally oriented slit-like opening (...).

Back 4

laryngeotracheal tube
laryngeal orifice

Front 5

Proliferation of the underlying ... forms swellings around the laryngeal orifice (epiglotal swelling and arytenoid swellings) from which the epiglottis, glottis, laryngeal cartilages and musculature will develop.

At the time, the laryngotracheal tube elongates downwards and penetrates the underlying ... mesoderm (gives rise to connective tissue structures, smooth mm, hyaline cartilage that surrounds upper part of respiratory tract).

Back 5

mesenchyme
splanchnopleuric

Front 6

look at slide 11-12

Back 6

ok

Front 7

DEVELOPMENT OF THE RESPIRATORY SYSTEM:

The epithelium of the respiratory system is derived from ... and the surrounding supportive cartilaginous and muscular tissue is derived from ....

Back 7

endoderm
splanchnic mesoderm

Front 8

Larynx Development:

Mesenchyme of the larynx is derived from the ... and ... pharyngeal arches - innervated by the ... nerve.

Back 8

4th
6th
vagus

Front 9

Larynx Development:

During development, the laryngeal opening is temporarily closed off by growth of the laryngeal ....

However, re-canalization of this region leaves folds of tissue that give rise to the ....

Back 9

epithelium
vocal cords

Front 10

What does the distal portion of the laryngotracheal tube develop into? (2)

Back 10

trachea and lungs

Front 11

The ... of the trachea from the esophagus and the eventual separation is critical.

In the absence of complete septation, a ... can develop – an abnormal connection between the trachea and esophagus

Back 11

septation
tracheo-esophageal fistula

Front 12

Trachea development:

Like the larynx, the trachea becomes filled in by cell proliferation but is then ... to become lined by ....

Back 12

recanalized
endoderm

Front 13

Lung Development:

The lungs grow into the narrow ... on each side of the foregut and eventually fill the space.

The pericardioperitoneal canals are separated from the peritoneal and pericardial cavities by the ... and ... folds.

Back 13

pericardioperitoneal canals
pleuroperitoneal and pleuropericardial

Front 14

Lung development:

Visceral mesoderm covering the lung epithelium becomes the ... and the somatic mesoderm lining the body wall becomes the .... The space between the pleura is the ....

Back 14

visceral pleura
parietal pleura
pleural cavity

Front 15

Lung development:

... – 4-7 weeks – outgrowth of trachea, right and left main bronchi and major airways
... – 5-17 wks – formation of bronchial tree up to a preacinar level
... – 16-26 wks – formation of the pulmonary acinus and of the future air-blood barrier; increase of capillary bed; epithelial differentiation; first appearance of ...
... – 24-38 wks – formation of transitory air spaces (alveoli starts to thin out)
... – 36 wks to 2 postnatal yrs – alveolarization by forming of ...
... – birth to 3 postnatal years – thinning of interalveolar walls; fusion of the capillary bilayer to a single layered network

Back 15

embryonic
pseudoglandular
canalicular
surfactant
saccular
alveolar
secondary septa
microvascular maturation

Front 16

Lung maturation:

Pseudoglandular (5-17 weeks)
-No ... exchange zones
-Lung resembles an ...

Canalicular (17-25 weeks)
-Terminal bronchioles enlarge and branch 2-3 respiratory bronchioles then 3-6 alveolar ducts. ... begin to form
*... – caudal slower than cranial

Back 16

gas
exocrine gland
Terminal sacs
Vascularized

Front 17

Lung maturation:

Terminal sac (25 weeks to 34 weeks) – blood flow and ...
-Epithelium ... to become type I like
-... grow in
-Blood air barrier forms
*Type I and type II cells
.Surfactant ... surface tension allowing expansion.

Alveolar period (late fetal to childhood)
-Surfactant
-Gas exchange
-Pulmonary vs systemic circulation
-... mature from age 3-8. Numbers increase from 50 million at birth and 300 million at age 8 (adult number)

Back 17

surfactant
thins
Capillaries
reduces
Alveoli

Front 18

look at slide 28

Back 18

ok

Front 19

Pseudoglandular:

5-17 weeks

formation of bronchial tree up to a ... level

development all the way up to the ...

Back 19

preacinar
terminal bronchioles

Front 20

In the pseudoglandular phase the lungs resemble a .... Precursors of the pneumocytes appear (... epithelium)

Back 20

gland
cuboidal

Front 21

look at slide 30-33

Back 21

ok

Front 22

Canalicular:

16-26 weeks

Formation of the pulmonary ... and of the future air-blood barrier, increased capillary bed, epithelial differentiation and first appearance of ...

Back 22

acinus
surfactant

Front 23

In the canalicular phase the ... pneumocytes differentiate out of the ... pneumocytes. The capillaries approach the walls of the ....

Back 23

type I
type II
acini

Front 24

look at slide 35-37

Back 24

ok

Front 25

Saccular:

24-38 weeks

-Formation of ...
-The number of capillaries increase around the acini.
-By 31 weeks, alveolar spaces are easily identified and the alveolar wall is thin with flat ... cell and capillary

Back 25

transitory air spaces (blood-air barrier)
type I

Front 26

look at slide 39-40

Back 26

ok

Front 27

At ... the lungs are partially filled with amniotic fluid.

The fluid is expelled through the mouth and nose and absorbed by the pulmonary ... and ....

Back 27

birth
capillaries and lymphatics

Front 28

Near the end of the sixth month, alveolar epithelial cells produce ... – a phospholipid rich fluid that lowers the surface tension at the interface between air and the alveolar cells.

Type ... cells are beginning to form surfactant in preparation for the birth

Back 28

surfactant
2

Front 29

Alveolar – last of fetal stages

36 wks to 2 years postnatal

The alveoli form from the terminal endings of the ... and with time ... their diameter.

After birth more and more alveoli form from the terminal endings of the ... and ... in diameter.

Back 29

alveolar sacculi
increase
alveolar
increase

Front 30

look at slide 44-45

Back 30

ok

Front 31

At birth, alveoli are well formed and contain ... pneumocytes.

Maturation of alveoli continue until about age ....

Back 31

both type I and II
8

Front 32

look at slide 46

Back 32

ok

Front 33

...:

Decreased levels of surfactant in the alveoli: usually due to prematurity.
-Inadequate surfactant leads to alveolar collapse on ...
-Damage to the alveolar cells results in the secretion of a “...” membranes (... membrane disease) – an accumulation of fluid in the alveolar sacs

Back 33

RDS – respiratory distress syndrome
expiration
hyaline
hyaline

Front 34

Formation of the pulmonary system:

The pulmonary system is formed by the ... arch.

1st thing that appears is ... of blood vessels that appear around developing lung buds. They meet up w/ the ... to form the pulmonary circuit.

Back 34

6th aortic
plexus
6th aortic arch

Front 35

look at slide 48

Back 35

ok