Lecture 14: Embryology of the Gut Flashcards
(116 cards)
What are the two foldings involved in primitive gut formation
Later folding and cephalo-caudal folding
What primary get layers makes up the gut?
Endoderm
What are structural derivatives of the ectoderm?
Skin and nervous system
What are structural derivatives of the mesoderm?
CT, cartilage, muscle, bone, and blood
What are the directions for the cephalic-caudal and lateral plate mesoderm folds?
Cepalo-caudal- inwards
Lateral plate mesoderm- lateral
both form the body wall and body because the head and tail region become distinct from one another
As these two folds in the embryo occur, a big space develops, what is that called?
Intraembryonic coelomic cavity
What are the 3 body cavities derived in the intraembryonic coelomic cavity in the adult
Pleural cavity, pericardial, peritioneal cavity
Compare the size of the embryo peritoneal cavity to the adult
Embryo is much larger than the adult due to the growth of the organs
Significant structures that arise from the folding of the lateral plate mesoderm in the adult
Visceral and parietal paritoneum
How is the primitive gut separated from the yolk sac
Lateral and cephalo-caudal folding
Will a connection between the yolk sac and the primitive gut still exist after folding? If so how?
Yes because the yolk stalk (vitaline duct or omphalomesenteric duct) remains connected but continues to narrow with time
What structures will become a part of the forgut?
Forms pharynx, esophagus, stomach, proximal half duodenum, liver, pancreas, gal bladder, lower respirtory system
What structures will become a part of the midgut
Forms distal duodeum, jejunum, illeum, large intestine up to proximal 2/3 of transverse colon
What is the midgut region connected to in the embryo
Yolk sac
What structures will become a part of the hindgut
Forms the lateral 1/3 of transverse colon, descending colon, sigmoid colon, rectum, gut part of anal canal
Allantois
Membrane that becomes incorporated into the embryo (in the hindgut region) and participates in the formation of the cloaca
How is the gut attaches to the back body wall?
Dorsal mesentery
Describe how the dorsal mesentery is formed
The cephalo-caudal and lateral foldings divides the mesoderm into the somatic (on the body) and splanchnic mesoderm (on the gut). The dorsal mesentery is a double layer fold of splanchnic mesoderm
Other than the dorsal mesentery, what else is derived from the splanchnic mesoderm?
Smooth muscle of GI tract
What organs are suspended by the dorsal mesentery
Every gut organs
What is the space between the somatic and splanchnic mesoderm called
Intraembryonic coelomic cavity
The ventral mesentery grows very early, what happens to the ventral mesentery when the liver begins to grow
The liver divides the mesentery into 2 parts- the falciform ligament and lesser omentum
What are two structural derivatives of the dorsal mesentery
Falciform ligament and lesser omentum
Where is the ventral mesentery present?
forgut (unlike dorsal mesentery)