Development Gastrointestinal System Flashcards
what does the ectoderm form?
the epidermis layer of the skin
the epithelium of the oral and nasal cavities and the nervous system and sense organs
what does the mesoderm result in the formation of?
forms muscle and connective tissue, bone and parts of the circulatory, urinary and genital systems
what does the endoderm result in the formation of?
forms mucosal epithelium and glands of respiratory and digestive systems
what does the thickening of oral epithelium form?
forms the ectodermal dental lamina
what results in the formation of the dental bud?
the dental lamina invaginates to form the dental bud
the dental bud expands and branches to become what?
it becomes the enamel organ (outer and inner enamel epithelium)
what is mesenchyme?
it is an embryonic connective tissue characterised by loosely associated cells and extra cellular matrix
where is most mesenchyme derived from?
it is derived from mesoderm
where are tooth connective tissues derived from?
they are derived from neural crest cells plus mesoderm
what is neuro-mesenchyme?
it is the mesenchyme from tooth connective tissues that are derived from neural crest cells plus mesoderm
slide 7,8,9
what are both minor and major salivary glands formed from?
from outgrowths of epithelium that push into the underlying mesenchyme
where are the gland acini and the ducts formed from?
the branches that push into the underlying mesenchyme - these branches become canalised
what does the primitive gut tube start as?
starts as a single tube of endoderm
SLIDE 11,12,13
what does the dorsal mesentery become?
it becomes: greater omentum, mesoduodenum, mesentery (mesojejunum and mesoileum), mesocolon and mesorectum
what does the ventral mesentery become?
it becomes the lesser omentum, coronary and falciform ligaments of the liver
caudally, what does the ventral mesentery become?
it becomes the median ligament of the urinary bladder
what lines the abdominal cavity?
serous membrane
position of spleen to stomach?
caudal
14,15,16,17
what does liver growth do to the orientation of the simple stomach?
it pushes the cranial end of the stomach to the left side
what happens in order for the fundus region to form?
increased growth along the left cranial end of the future greater curvature
rumen develops as an expansion of what?
of the fundus
the reticulum arises as a…?
as a caudoventral pocket of the developing rumen
what does the omasum develop as?
it develops as a bulge along the lesser curvature
where does the abomasum develop from?
develops from the rest of the stomach
what happens later in the development of the rumen?
the rumen ‘flips’ caudally to be on top of the abomasum and the reticulum is cranial
20,21,
Where does the pancreas arise from?
it arises from the same portion of the foregut as the liver as two endodermal diverticulum
what happens after the migration of ventral pancreas?
two primordia fuse
pancreas - how does the islet tissue develop?
the islet tissue develops by budding from the ducts
what does the dorsal bud of the pancreas develop into?
they develop into major parts of the pancreas
what does the midgut give rise to?
it gives rise to the middle parts of the digestive canal
what does the midgut consist of?
duodenum (caudal part)
jejunum
caecum
ascending colon
hindgut consists of?
transverse colon (first two thirds)
location of midgut?
it hangs from the dorsal body wall by a short mesentery
describe the early growth of the intestinal loop?
it is very rapid, causing it to hang in a loop from elongated mesentery
