SYSTEM
RESPIRATORY
THE
OF
DEVELOPMENT
its
retains
tube
esophagus.The
the
from
tube
tracheal
-
laryngo
the
of
separation
After
tube
the
of
part
upper
the
eminence.Then
hypobrancheal
the
behind
just
opening
2
to
in
divides
part
caudal
its
pharynx,while
the
to
in
opens
which
larynx
the
becomes
bud.
lung
as
known
mass
mesodermal
a
by
surrounded
is
one
,each
bronchi
principal
fourth
the
of
mesoderm
the
from
mainly
develop
larynx
the
of
muscles
&
cartilages
The
&
cartilages
the
arches,while
sixth
&
fifth
the
from
contribution
some
with
arch
branchial
surrounds
which
mesoderm
splanchnic
the
from
develop
bronchi
&
trachea
the
of
muscles
tube.
tracheal
-
laryngo
the
lung
future
bronchus(
each
of
end
terminal
the
surround
to
comes
bud
lung
The
pleura
of
rs
laye
2
the
form
to
sac
pleural
the
to
in
itself
invaginates
bud
substance).The
the
by
infiltrated
is
bud
lung
the
time
mean
the
at
&
cavity
pleural
the
with
along
th
17
to
up
bronchioles
respiratory
&
segmentation(lobar,lobular,terminal
its
&
bronchus
follows:
as
stages
four
gh
throu
passes
development
branching)..Lung
its
of
generation
weeks.
th
16
-
th
5
between
gland
a
like
mass
solid
a
is
which
stage
Pseudoglandular
-
1
gestation.
of
weeks
th
26
–
th
16
between
stage
Canalicular
-
2
month
th
6
of
end
the
between
stage)
epithelial
alveolar
I
Type
period(
sac
Terminal
-
3
development.
intrauterine
of
month
th
7
of
mid
the
To
produced
cells
the
where
born),
new
of
tissue
lung
(
stage
epithelial
alveolar
2
Type
-
4
alveoli.
the
of
collapse
the
prevent
to
Surfactant
enzyme
The
Anomalies
Congenital
laryngotracheal
the
of
lips
the
of
fusion
incomplete
to
,due
fistula
esophageal
-
Tracheo
-
1
Groove.
to
or
lob
one
of
absence
to
lead
may
tube
tracheal
-
laryngo
of
branching
Abnormal
-
2
segment.
bronchopulmonary
accessory
or
lobe
accessory
an
of
formation
E.
surfactant
in
deficiency
or
absence
to
due
(RDS)
syndrome
distress
Respiratory
-
3
Tongue
The
of
Development
followings:
the
from
develops
thirds
two
anterior
The
first
the
of
end
ventral
the
between
situated
elevation
an
is
which
impar
Tuberculum
-
1
)
eminence
hypobranchial
to
anterior
(lies
arch
chial
bran
the
of
side
each
on
arch
first
the
of
end
ventral
the
from
arising
swellings
lingual
Two
-
2
2/3.
anterior
form
to
impar
ulum
tuberc
with
fuse
swellings
2
impar.These
tuberculum
&
third
the
to
related
is
which
eminence
Hypobranchial
from
develops
third
posterior
The
a
at
tongue
the
of
2/3
anterior
the
with
fuses
eminence
Hypobranchial
arches.This
fourth
erminalis.
t
sulcus
called
line
shaped
-
V
to
migrates
which
somites
occipital
the
by
forms
tongue
the
of
component
muscular
The
them
with
carry
they
&
uscles
m
its
forms
and
tongue
the
of
covering
epithelial
the
enter
nerve.
Hypoglossal
the
Tongue
The
of
Anomalies
Congenital
tongue.
the
of
absence
incomplete
or
complete
either
sia
Aglos
-
1
ward.
back
and
end
anterior
pointed
its
from
tongue
Bifid
-
2
frenulum.
short
to
due
tongue
Short
-
3
tongue.
large
abnormal
is
which
Macroglossia
-
4
LIMBS
THE
OF
DEVELOPMENT
near
body
the
of
part
ventrolateral
the
on
Buds
Limb
as
start
limbs
the
of
Development
the
mesoderm,where
plate
lateral
the
in
cells
Mesenchymal
from
weeks
th
4
the
of
end
the
.Each
th
29
day
at
appear
limbs
lower
of
those
and
th
27
day
at
appears
limb
upper
the
of
buds
gate
elon
buds
the
Ectoderm,then
by
covered
Mesenchyme
of
core
a
fact
in
is
first
at
bud
&
axial
-
pre
the
that
so
flattened
becomes
&
cells
mesenchymal
of
proliferation
the
by
cervical
caudal
the
opposite
seen
are
limbs
upper
of
buds
appear.The
surfaces
axial
-
post
gain
and
ments
seg
sacral
&
lumbar
the
opposite
limbs
lower
of
those
segments,while
respectively..
Plexuses
Lumbosacral
&
Brachial
the
from
innervation
of
laterally,while
directed
is
Thumb
the
that
so
laterally
rotates
limbs
upper
of
buds
The
rays
Digital
on
medially.Later
directed
is
Hallux
the
that
so
medially
rotates
limbs
lower
foot
the
in
toes
for
,and
weeks
th
6
of
end
the
by
fingers
the
form
to
plate
hand
the
in
appear
down.
break
tissue
to
due
disappear
rays
digital
between
notches
the
and
weeks
th
7
at
plate
by
weeks,thus
th
5
in
late
centers
chondrification
as
starts
Limbs
the
of
es
Bon
of
Formation
th
8
and
limbs)
(upper
weeks
th
7
cartilaginous.At
is
skeleton
limbs
weeks
th
6
of
end
the
e
th
form
to
appears
cartilage
the
of
middle
the
in
centers
ossification
limbs)
(lower
weeks
end
the
by
seen
are
bones
long
the
in
centers
ossification
primary
limbs.Then
the
of
bones
age.
the
of
year
one
at
starts
bones
carpal
the
in
life,while
intrauterine
of
weeks
th
12
the
of
to
rise
gives
e
myotom
each
where
Myotomes
the
from
start
development
muscles
The
myotome
striations.Each
its
with
fibers
muscle
forming
together
fused
that
myoblasts
&
ramus)
ventral
by
innervates
&
body
of
aspect
ventral
Hypomere(on
the
to
rise
gives
s).
ramu
dorsal
by
innervates
&
body
of
aspect
dorsal
(on
Epimere
becomes
Elbow
the
that
so
degrees
90
laterally
rotates
limbs
upper
The
:
Rotations
Limbs
limb.
of
aspects
posterior
&
lateral
the
on
lie
muscles
extensor
the
&
posteriorly
directed
the
&
anteriorly
directed
is
Knee
the
that
so
too
degree
90
aaly
medi
rotates
limbs
lower
The
limb..
of
aspect
anterior
on
muscles
extensor
LIMBS
OF
ANOMALIES
CONGENITAL
Thalidomide.
to
due
stump)
Meromelia(rudimentary
&
limbs)
of
absence
Amelia(complete
-
1
deformity.
claw
lobster
as
foot
&
hand
Cleft
-
2
.
digits
short
very
means
ch
whi
Brachydactyly
-
3
digits.
supernumerly
means
which
Polydactyly
-
4
2200.
/
1
is
incidence
its
)
osseous
or
us
cutaneo
Syndactyly(
-
5
1000.
/
1
incidence
its
varus)
equino
talipus
foot(
club
Congenital
-
6
1500
/
1
is
incidence
its
males
in
than
male
fe
in
more
is
which
hip
dislocated
Congenital
-
7
laxity.
joint
&
acetabulum
of
development
abnormal
to
due
week)
th
5
(
days
32
at
like
finger
paddle
buds
limb
upper
The
weeks).
th
5
of
end
(
days
35
at
formed
is
plate
Hand
.
days
44
-
42
at
appears
plate
hand
in
rays
Digital
48.
-
46
days
at
webbed
&
short
are
w,fingers
Elbo
at
bending
Limbs
56.
-
54
days
at
separated
are
&
distinct
are
Fingers
.
event
each
for
date
above
the
after
days
3
-
2
about
limbs
lower
the
for
Those
LIMBS
LOWER
LIMBS
UPPER
wks
th
5
in
late
or
mid
at
Appears
wks
th
4
of
end
the
by
appear
Buds
-
1
middle
at
Appears
joints
future
for
Contrictions
-
2
weeks
th
7
of
wks
th
6
late
during
appears
weeks
th
8
of
beginning
At
wks
th
7
at
starts
Ossifications
-
3
wks
th
9
of
beginning
at
Appears
weeks
th
8
during
appear
Muscles
-
4
