The embryo is now 2.5 mm long from crown to rump. The liver, lungs, spleen, pancreas and thyroid gland are now developing. The intestines now consist of a foregut, midgut and hindgut. These parts will later develop into the oesophagus (gullet), stomach and the final intestines. The umbilical cord has now formed. The heart continues to beat with only one chamber, and the circulation is still developing. The head is beginning to take shape, but is still bent forwards.