Gastrointestinal Tract - Carnegie Stage 13

Introduction

The individual serial slices have also been incorporated into a 3D model of this embryo.

Gastrointestinal

Stage 13/14 Embryo

Stage 13 Embryo - Gastrointestinal Tract

Section	Name	Description
	B1L B2L	Pharynx. Crest in ventral floor of pharynx formed by fusion of 3rd pharyngeal arches = hypopharyngeal eminence (precursor of root of tongue). Rathke's pouch forming the rudimentary adenohypophysis (anterior pituitary).
	B3L	Rudimentary thyroid ventral to aortic sac (also seen in B2, ventral to the hypopharyngeal eminence).
	B4L	Caudal pharynx compressed dorsoventrally.
	B7L	Glottis drawn off from pharyngeal foregut. Nasal placodes. Pulmonary arteries.
	C1L C2L	Commencement of trachea and oesophagus with dense mesenchyme. Right nasal pit.
	C3L C4L	Common cardinal vein in the posterior wall of the intraembryonic coelom. The pleuropericardial folds which contribute later to the formation of the pleura and pericardium. In C4, junction of right common cardinal vein with dorsal wall of sinus venosus. Left nasal pit.
	C5L	Smaller oesophagus, expanding trachea. Note ventral anchoring of attachment site is at the most cranial extension of the septum transversum. Note also that this attachment now divides the intraembryonic coelom around the trachea into two canals, the L and R pleuro (pericardio-peritoneal) canals. (Canals are lined by coelomic mesothelium and are continuous with whole I-E coelom - they will be referred to hereafter simply as coelomic canals). Note the pleuroperitoneal fold on the medial side of the R common cardinal vein - this fold will form part of the diaphragm.
	C5L C6L	Lateral extension of pulmonary mesenchyme is moulded to shape of coelomic canals. Oesophagus lumen obliterated (common site of oesophageal atresia and/or tracheo-oesophageal fistula). Prominent R pleuroperitoneal fold.
	C7L	Note dorsal extent of coelomic canals. Oesophagus lumen reappears caudal to bifurcation. Distinct R (smaller on L) pleuroperitoneal fold below the common cardinal vein.
	D1L	Oesophagus/stomach junction. Coelomic canals.
	D2L	Ovoid stomach with developing space of the lesser sac on R. Dorsal and ventral attachments of the mesenchyme are now known as dorsal and ventral mesogastria. Coelomic canals.
	D3L	Rotation of stomach (seen from above) to right side. Note change in outline of coelomic canals due to presence of liver. Lesser sac. Note thick mesothelium lining the coelom along left edge of stomach, the primordium of the spleen and greater omentum along greater curvature. Liver embedded in septum transversum (ventral border of septum transversum contributes to diaphragm).
	G7L	Caudal pharynx (extending laterally, ventral to dorsal aorta - cf B4). Stomach, mesentery
	G6L	Narrow oesophagus. Tracheal bifurcation dorsal to sinus venosus.

All Sections

Stage 13 (serial labeled images)

A1L	A2L	A3L	A4L	A5L	A6L	A7L
B1L	B2L	B3L	B4L	B5L	B6L	B7L
C1L	C2L	C3L	C4L	C5L	C6L	C7L
D1L	D2L	D3L	D4L	D5L	D6L	D7L
E1L	E2L	E3L	E4L	E5L	E6L	E7L
F1L	F2L	F3L	F4L	F5L	F6L	F7L
G1L	G2L	G3L	G4L	G5L	G6L	G7L

Glossary Links

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Cite this page: Hill, M.A. (2024, April 16) Embryology Gastrointestinal Tract - Carnegie Stage 13. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Gastrointestinal_Tract_-_Carnegie_Stage_13

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G