Development of the digestive tract AHS1 Flashcards
What is gastrulation?
Formation of the trilaminar germ disc/three layers
What are the two different types of lateral plate mesoderm?
Somatic and splanchnic
What area of the body is somatic lateral plate mesoderm?
Body wall
What area of the body is splanchnic lateral plate mesoderm?
Viscera
Also muscle layers of the gut tube (even though rest of GI tract is endoderm)
What does the ectoderm make?
Nervous system, adrenal medulla, skin
What does the mesoderm make?
Bone, cartilage, muscles, CV system, limbs, UG tract, spleen
What does the endoderm make?
The lining of the gut, GI tract accessory organs (liver, pancreas etc.). respiratory tract (the parts of the body that have openings to the outside)
What layer are the lips derived from?
The ectoderm
What layer are the mucous membranes
Endoderm
What is the area where the endoderm and ectoderm come in contact to form the mouth called?
Oro-pharangeal membrane
What is the area where the endoderm and ectoderm come in contact to form the anus called?
Anal membrane
What does the septum transversum form?
The diaphragm and cranioventral mesentery
What mesenteries does the foregut have?
Dorsal and ventral mesentery
turn into mesoduodenum etc. when the GI tract starts to differentiate into different parts
What mesenteries does the midgut have?
Only a dorsal mesentery (due to amniotic sac formation)
What mesenteries does the hindgut have?
Dorsal and ventral mesenteries
How does the stomach start to develop?
By forming a bulge dorsally in the GI tract
Where does the spleen develop from?
From the mesoderm (rather than the endoderm like the GI tract)
Where does the spleen develop in the abdomen?
In the dorsal mesogastrium/mesentery
How does the stomach further develop in the abdomen/twist?
It rotated 90 degrees anticlockwise around the cranio-caudal axis so that the greater curvature is on the left (or right looking ventrally).
It then rotates 45 degrees to run more transversely so top is on the left and bottom is on the right.