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Dermatology
Skin Development and Maintenance
Built from Dermatology, 5th Edition
What’s inside
10 sections · 78 slides
Overview
- What this topic covers
- Timeline of skin development before and after birth
Embryonic Origin of the Skin
Which embryonic layer gives rise to each skin cell type
- Germ layers and gastrulation
- Two fates of the ectoderm
- The neural crest and the melanocyte
- Where the dermis comes from
- Clinical link: Waardenburg syndrome
Epidermal Development
From a single sheet of cells to a protective barrier
- From single sheet to layered epidermis
- Epidermal stratification begins
- Epidermal stratification, step by step
- Development of the epidermis
- Terminal differentiation and cornification
- Fetal and neonatal skin under the microscope
- Genetic epidermal defects and the lines of Blaschko
- Collodion baby and ichthyosis
- Harlequin ichthyosis
- Why premature skin is fragile
- Premature, newborn and adult skin compared
- Comparative features of premature, newborn, and adult skin
- Comparative features of premature, newborn, and adult skin (continued)
- Comparative features of the papillary dermis
- Comparative features of the reticular dermis and hypodermis
Specialized Cells of the Epidermis
Melanocytes, Langerhans cells, and Merkel cells arrive
- Melanocyte migration
- Melanocyte numbers and pigment timing
- Dermal melanocytes and blue nevi
- Langerhans cells and Merkel cells
- Clinical link: piebaldism and Waardenburg syndrome
Development of the Dermis and Subcutis
Building the deeper, supportive layer of skin
- Dermal fibroblasts are not all alike
- Early dermal matrix
- Papillary vs reticular dermis emerge
- Vessels, nerves, and fat in the dermis
- Clinical link: Ehlers–Danlos syndrome and cutis laxa
- Clinical link: Goltz syndrome
- Dermis, layer by layer
Dermal-Epidermal Junction
The anchoring layer that binds epidermis to dermis
- What the dermal-epidermal junction does
- How the junction matures
- Layers of the dermal-epidermal junction
- Clinical link: epidermolysis bullosa
Development of Skin Appendages
Hair, nails, and sweat and oil glands
- Skin appendages overview
- A shared building plan
- Hair follicle induction
- Fetal development of the hair follicle
- Two bulges on the developing follicle
- Hair follicle maturation and signaling genes
- The hair growth cycle
- Hair cycling continues after birth
- Sebaceous gland development
- Nail development
- Eccrine sweat gland and fingerprint development
- Apocrine gland development and gland timing
- Clinical link: ectodermal dysplasias
- Other appendage-related gene disorders
Skin Stem Cells
How the skin keeps renewing and repairing itself
- What makes a cell a stem cell
- Holoclones: stem cells grown in the lab
- Cutaneous stem cell populations
- Cutaneous stem cells
- Cutaneous stem cells (continued)
- Epidermal stem cells and their location
- Hierarchical and stochastic models of keratinocyte stem cells
- Hair follicle bulge stem cells
- Keratinocyte and melanocyte stem cells in the bulge
- The hair bulb: matrix cells
- Stem cells can change their fate (plasticity)
- Pluripotent skin cells and iPS cells
- Stem cell strategies for genetic skin disease
- Strategies for stem cell therapy of genetic skin disorders
- Bone marrow and iPS approaches for severe EB
Prenatal Diagnosis of Genodermatoses
Detecting inherited skin disease before birth
- From skin biopsy to DNA testing
- Preimplantation genetic diagnosis
Skin Development in Postnatal Life
Why embryology still matters after birth
- Developmental pathways reused after birth
- Why this knowledge matters going forward
- Key takeaways
- References
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- Dermatology, 5th Edition (2-Volume Set)