UNSW Embryology

Integumentary Development - Dermatomes

© Dr Mark Hill (2009)

Acknowledgements

Introduction

Dermatomes refer to regions of the skin innervated by a segmmental spinal nerve.

Prospective epidermal cells expressing a cytokeratin gene (green)

(Image- Lance Davidson)

Page Links

Introduction | Reading | Development Overview | Terms | References

Some Recent Findings

Reading

• Human Embryology (2nd ed.) Larson Chapter 14 p443-455
• The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud Ch20: P513-529
• Before We Are Born (5th ed.) Moore and Persaud Ch21: P481-496
• Essentials of Human Embryology Larson Ch14: P303-315
• Human Embryology, Fitzgerald and Fitzgerald
• Color Atlas of Clinical Embryology Moore Persaud and Shiota Ch15: p231-236
• Selected References- Hair development

 

Development Overview

• Ectoderm and Mesoderm Origin

4 weeks

• simple ectoderm epithelium over mesenchyme.

1-3 months

• ectoderm- germinative (basal) cell repeated division of generates stratified epithelium.
• mesoderm- differentiates into connective tissue and blood vessels.

4 months

• basal cell- proliferation generates folds in basement membrane.
• neural crest cells- (melanocytes) migrate into epithelium. These are the pigment cell of the skin.
• embryonic connective tissue- differentiates into dermis, a loose ct layer over a dense ct layer. Beneath the dense ct layer is another loose ct layer that will form the subcutaneous layer.
• Ectoderm contributes to nails, hair follictles and glands.
• Nails form as thickening of ectoderm epidermis at the tips of fingers and toes. These form germinative cells of nail field.
• Cords of these cells extend into mesoderm forming epithelial columns. These form hair follocles, sebaceous and sweat glands.

5 months

• Hair growth initiated at base of cord, lateral outgrowths form associated sebaceous glands.
• Other cords elongate and coil to form sweat glands.
• Cords in mammary region branch as they elongate to form mammary glands. These glands will complete development in females at puberty. Functional maturity only occurs in late pregnancy.

 

More detailed Overview? of other Integumentary Structures

References

Reviews

An entire recent issue of International Journal of Developmental Biology on Skin Development Int. J. Dev. Biol. 48:(2004) "Half a century of research into the developmental biology of the integument"

PubMed

Search PubMed Now: term=skin+development | term=hair+development | term=tooth+development | (Requires internet connection)

1999 Reference Lists

Requires no internet connection. Selected Lists of References from PubMed March 1999 search results are available for School of Anatomy computers without internet access. Computers with internet access can search from either Page 2 or PubMed Internet Access

• Selected references development of Hair
• Selected references development of Teeth
• Selected Research Articles and Reviews

Glossary of Terms

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S |T | U | V | W | X | Y | Z

Quick Links

Integumentary Development Pages:

Abnormalities | Stage 13/14 | Stage 22 | Histology | Dermatomes | Glands | Mammary Glands | Teeth | Hair | Nails | Keratin | Overview |

Development Notes ----------------- Menstrual Cycle Week 1 Week 2 Week 3 Week 4 Placenta Serial Images Genes/DNA Molecular Dev Abnormal Dev Postnatal Dev Notes Index

System Notes ----------------- Heart/Cardiovascular Respiratory Coelomic cavity Gastrointestinal Tract Head and Neck Neural Neural Crest Eye Ear Nose Endocrine Urogenital Musculoskeletal Integumentary

Movies ----------------- Embryo Growth Ultrasound Week 1 Week 2 Week 3 Week 4 Stage 13/14 Stage 22 Neural Head and Neck Heart Vasculature Gastrointestinal Urogenital Other Embryos Larsen Internet

Other Embryos ----------------- Chicken Fly Frog Mouse Rabbit Rat Worm Zebrafish Guinea Pig

UNSW Embryology ISBN: 978 0 7334 2609 4

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