UNSW Embryology

Stage 13/14 Embryo Section C5 (labelled)

Stage 13/14 | C5L | Unlabelled | Tutorial | Previous | Next

St 13/14 Systems -------------- Coelomic Cavity Endocrine Gastrointestinal Head and Neck Heart Musculoskeletal Nervous System Neural Crest Organs of Senses Respiratory System Skin, Hair and Nails Urogenital Placenta

St 13/14 Labelled Embryo Sections A1 A2 A3 A4 A5 A6 A7 B1 B2 B3 B4 B5 B6 B7 C1 C2 C3 C4 C5 C6 C7 D1 D2 D3 D4 D5 D6 D7 E1 E2 E3 E4 E5 E6 E7 F1 F2 F3 F4 F5 F6 F7 G1 G2 G3 G4 G5 G6 G7

St 13/14 Unlabelled Embryo Sections A1 A2 A3 A4 A5 A6 A7 B1 B2 B3 B4 B5 B6 B7 C1 C2 C3 C4 C5 C6 C7 D1 D2 D3 D4 D5 D6 D7 E1 E2 E3 E4 E5 E6 E7 F1 F2 F3 F4 F5 F6 F7 G1 G2 G3 G4 G5 G6 G7

St 13/14 3D Movies Central Nervous System Cardiovasular Gastrointestinal Tract 3D Models

Image Features

Craniofacial Development and Pharynx

C1-C7: Beginning of trachea, oesophagus. Nasal placodes (nasal pit forming on one side). Forebrain. note proximity of nasal pit to prosencephalon (future site of olfactory nerve). In C2-C4, identify the medial and lateral nasal swellings.

Respiratory System

C5: 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.

Lateral extension of pulmonary mesenchyme is moulded to shape of coelomic canals. R common cardinal draining directly into sinus venosus; L common cardinal vein with prominent L pleuropericardial fold. Oesophagus lumen obliterated (common site of oesophageal atresia and/or tracheo-oesophageal fistula). Prominent R pleuroperitoneal fold.

Development of the Nervous System

C1-5: Forebrain. Also identify the sulcus limitans separating the alar and basal plates.

About Stage 13/14 Embryo

The Carnegie stage 13/14 Pig Embryo is 6mm in size and approximately equal to day 42 Human Embryo. Use the serial images to identify internal features and relationships that exist within the embryo at this stage. Then compare these images with the external appearance of the embryo at this stage and the later internal features of the stage 22 embryo.

Note that the nomenclature "stage 13/14" is not an actual Carnegie stage but indicates that the embryo stage lies between or has features of both stage 13 and stage 14 embryos.

Levels shown on whole embryo are only approximate.

Note that not all embryo features are labelled.

Hint: clicking on each section image above will also step you through the whole embryo in sequence.

UNSW Embryology ISBN: 978 0 7334 2609 4

UNSW CRICOS Provider Code No. 00098G