Template:Week 5 Embryo Stages and Events table
| Week 5 - Human Embryo Stages and Events (GA week 7) | ||
|---|---|---|
| Embryo Week: Week 1 | Week 2 | Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Week 9 | ||
| Event | ||
| pituitary - Week 5 elongation, contacts infundibulum, diverticulum of diencephalon
heart - Week 5 septation starts, atrial and ventricular respiratory - Week 5 left and right lung buds push into the pericardioperitoneal canals (primordia of pleural cavity) respiratory - Week 5 to 17 lung histology - pseudoglandular hearing - Week 5 cochlear part of otic vesicle elongates (humans 2.5 turns) | ||
| Stage 14 |  mesoderm - continued segmentation of paraxial mesoderm (somite pairs), heart prominence Head - 1st, 2nd and 3rd pharyngeal arch, forebrain, site of lens placode, site of otic placode, stomodeum Body - heart, liver, umbilical cord, mesonephric ridge visible externally as bulges. Limb - upper and lower limb buds growing neural - first appearance of the future cerebral hemispheres. Cerebellar plate differentiated to an intermediate layer, and future rhombic lip identifiable[1] liver hepatic gland and its vascular channels enlarge, hematopoietic function appears[2] | |
| Stage 15 |  neural - cranial nerves (except olfactory and optic) are identifiable in more advanced embryos[3] | |
| vision - 35 to 37 days retinal pigment present | ||
| Note - the day timing of stages is only approximate, system names link to first page of that specific system, and events are based upon the literature cited below. | ||
References
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