Transcript Development of the digestive system

Digestive System
Alimentary Canal develops from endoderm and splanchnic mesoderm
Formation of the human digestive system, depicted at about (A) 16 days, (B) 18 days, (C) 22 days, and (D) 28 days.
Digestive System
Alimentary Canal develops from endoderm and splanchnic mesoderm
four layers of the digestive tract the mucosa (1),
the submucosa (2),
the muscularis (3),
the serosa (4).
Peritoneum visceral vs parietal
Mesentery
)
Epi Ecto invaginates to meet endo
to form Stomodeum &
Proctodeum
A septum separates the cloaca into
anus (dorsal) and urogenital
(ventral
sagittal view of the 6-week embryo. The stomach region has begun to dilate, and the
pancreas is represented by two buds that will eventually fuse.
Alimentary Canal and Association Organs
Differentiation of associated organs at the level of the forming stomach occurs both dorsally (spleen) and
ventrally (liver).
respiratory tract and aveolar epithelium are endoderm in origin
with mesoderm contributing surrounding tissue
the respiratory system does not carry out its physiological
function (of gas exchange) until after birth.
The lungs go through distinct phases of development and
late in fetal development respiratory motions and amniotic
fluid are thought to have a role in lung maturation.
Development of this system is not completed until the last
weeks of Fetal development, just before birth. Therefore
premature babies have difficulties associated with
insufficient surfactant (end month 6 alveolar cells type 2
appear and begin to secrete surfactant).
In the head/neck region, the pharynx forms a major arched
cavity within the phrayngeal arches.
The upper row of illustrations are sections through the embryo at the plane indicated, showing the fates
of the pharyngeal pouches. The first forms the external auditory passages, while the second pouch
expands, eventually covering pouches 2, 3, and 4