40 Questions
What is the function of the oropharyngeal membrane in the primordial gut?
It closes the cranial end of the primordial gut
Which part of the primitive gut gives rise to the pancreas?
Foregut
What is the name of the structure that connects the midgut to the yolk sac?
Omphaloenteric duct
During which week of embryonic development does the primitive gut form?
4th week
What is the function of the cloacal membrane in the primordial gut?
It closes the caudal end of the primordial gut
Which of the following organs does not develop from the endoderm?
Heart
What is the name of the region of the primitive gut that gives rise to the small intestine?
Midgut
What is the purpose of the umbilical vesicle in embryonic development?
It provides nutrients to the embryo
From which parts of the embryonic gut tube does the duodenum develop?
Caudal part of the foregut and cranial part of the midgut
What happens to the lumen of the duodenum during the 5th and 6th weeks?
It becomes progressively smaller and is temporarily obliterated
What is the result of vacuolation of epithelial cells in the duodenum?
The duodenum becomes recanalized
From which pancreatic bud does the uncinate process and part of the head of the pancreas develop?
Ventral pancreatic bud
What happens to the ducts of the pancreatic buds as they fuse?
They anastomose, or open into one another
What is the origin of the pancreatic duct?
Duct of the dorsal bud and distal part of the duct of the ventral bud
What is the shape of the duodenum as it develops?
C-shaped
In which layer does the ventral pancreatic bud develop?
Between the layers of the ventral mesentery
What gives rise to the epithelium of the cranial and caudal ends of the alimentary tract?
Ectoderm of the stomatodeum and anal pit
What is the origin of the muscular and connective tissue and other layers of the wall of the digestive tract?
Splanchnic mesenchyme
What is the result of the layers of the splanchnic mesoderm merging in the midline?
Formation of the dorsal mesentery
What remains connected to the yolk sac via the yolk duct?
Midgut
Which part of the digestive system develops from the foregut?
Esophagus and stomach
What is the name of the cavity that the intra-embryonic body cavity is initially connected to?
Extra-embryonic body cavity
What gives rise to most of the epithelium and glands of the alimentary system?
Endoderm of the primordial gut
What is the origin of the cranial half of the transverse colon?
Midgut
At which stage of embryonic development does the pharynx become abruptly narrowed?
4-week-old embryo
What is the fate of the connection between the midgut and the yolk sac?
It becomes narrower
What develops from the endoderm?
Epithelium and glands of the alimentary system
What is the function of the longitudinal tracheoesophageal folds?
To form the esophagotracheal septum
Which part of the digestive system develops from the hindgut?
Caudal half of transverse colon and descending colon
What is the relationship between the intra-embryonic body cavity and the extra-embryonic body cavity?
They are initially connected but later separate
What is the origin of the pancreas?
Foregut
What is the result of the fusion of the longitudinal tracheoesophageal folds?
Formation of the esophagotracheal septum
What is the ventral part of the cranial portion of the foregut divided into?
Larynx, trachea, bronchi, and lungs
What is the epithelial lining of the esophagus in its earlier stages?
Stratified columnar
At what week does the esophageal lumen recanalize?
8 weeks
What is the final epithelial lining of the esophagus?
Stratified squamous
When does the esophagus reach its final relative length?
7th week
What is the characteristic of the stomach in its early formation?
Dilated region with a shape similar to the adult stomach
What are the two concomitant positional shifts that bring the stomach to its adult configuration?
Not specified in the content
What is the dorsal part of the cranial portion of the foregut divided into?
Oropharynx and esophagus
Study Notes
Development of Digestive System
Primitive Gut
- Forms during the 4th week of development
- Head, caudal eminence, and lateral folds incorporate the dorsal part of the umbilical vesicle (yolk sac)
- Closed at its cranial end by the oropharyngeal membrane and its caudal end by the cloacal membrane
- Divided into three parts: foregut, midgut, and hindgut
Foregut Derivatives
- Primordial pharynx and its derivatives
- Lower respiratory system
- Esophagus and stomach
- Duodenum (just distal to the opening of the bile duct)
- Liver, biliary apparatus (hepatic ducts, gallbladder, and bile duct), and pancreas
Midgut Derivatives
- Lower duodenum
- Jejunum and ileum
- Cecum and vermiform appendix
- Ascending colon
- Cranial half of transverse colon
Hindgut Derivatives
- Caudal half of transverse colon
- Descending colon
- Rectum
- Superior part of anal canal
Foregut Development
- Esophagus: forms from the cranial part of the foregut
- Respiratory diverticulum appears in the 4th week
- Esophagotracheal septum forms at the end of the 5th week
- Duodenum: forms from the caudal part of the foregut and cranial part of the midgut
- Duodenum grows rapidly and forms a C-shaped loop
- Lumen of the duodenum becomes progressively smaller and is temporarily obliterated due to proliferation of epithelial cells
- Duodenum normally becomes recanalized by the end of the embryonic period
Pancreas Development
- Develops from dorsal and ventral pancreatic buds
- Ventral bud grows between layers of the ventral mesentery
- As the duodenum rotates to the right and becomes C-shaped, the ventral bud is carried dorsally with the bile duct
- Ventral pancreatic bud forms the uncinate process and part of the head of the pancreas
- Pancreatic buds fuse, and their ducts anastomose
Esophagus Development
- Epithelium changes from stratified columnar to multilayered ciliated and finally to stratified squamous
- Esophagus elongates rapidly and reaches its final relative length by the seventh week
Stomach Development
- Recognizable as a dilated region with a shape similar to the adult stomach
- Two concomitant positional shifts bring the stomach to its adult configuration
General Development
- The endoderm of the primordial gut gives rise to most of the epithelium and glands of the alimentary system (liver and pancreas)
- The epithelium of the cranial and caudal ends of the alimentary tract is derived from ectoderm of the stomatodeum and anal pit (proctodeum), respectively
- The muscular and connective tissue and other layers of the wall of the digestive tract are derived from the splanchnic mesenchyme surrounding the primordial gut
This quiz covers the formation of the primitive gut during embryonic development, specifically in the 4th week of gestation. It is a part of the 1st year medicine curriculum, focusing on histology and embryology.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
