File:Fetal integumentary histology 01.jpg

Fetal Integumentary Histology

• 14 weeks - the epidermis consisted of a basal layer, an intermediate cell layer and periderm.
• 20 weeks - the number of intermediate cells layers was increased and developing hair follicles were visible.
• adult skin - contained basal, spinous, granular and cornified layers.

Note these ages appear to be LMP - This study gestational ages were estimated by menstrual age and ranged from 13 to 22 weeks. The embryo gestational ages and numbers were as follows: gestational age 13 weeks (1), 14 weeks (1), 16 weeks (1), 17 weeks (2), 18 weeks (2), 19 weeks (4), 20 weeks (4), 21 weeks (3), 22 weeks (3).

Scale bars 100 μm

In early gestation (13–14 weeks), fetal epidermis contained a basal layer, one or two intermediate layers and a periderm. At 14 weeks, the fetal dermis consisted of a finely fibrillar dermis that contained many cells. From 16 weeks of gestation, hair pegs were visible that projected into the dermis. The dermis was organized into two regions: an upper fibrillar papillary region and a deep reticular region that contained larger fibers. During further development, the number of epidermal cell layers increased and the hair pegs matured into hair follicles. Developing eccrine sweat glands were detected from week 21.

Links: Integumentary System Development

Reference

<pubmed>19701759</pubmed>| PMC2799629 | Arch Dermatol Res

© Coolen NA, Schouten KC, Middelkoop E, Ulrich MM. 2009 Open Access - This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Original file name: Fig. 1 403_2009_989_Fig1_HTML.gif (original figure increased in size)