Development of skin

(I) Epidermis:

  • Ectoderm
  • Neural crest – melanoblasts (melanin secreting cells)

(II) Dermis – paraxial mesoderm – dermatome

(III) Subcutaneous tissue – lateral plate mesoderm – somatic layer

(IV) Hairs:

  • Solid ectodermal buds sink into underlying mesenchyme
  • Forms hair bud, which is invaginated by mesoderm
  • Forms hair papilla
  • Muscle fibers attatch to hair follicles – errector pili muscles
  • Hair bulb central cells elongate and keratinize – hair shaft
  • Fetus first hair – lanugo hair

Image result for Development of hair

(V) Sweat glands:

  • Solid ectodermal buds sink into underlying mesenchyme
  • Terminal end coils and it canalizes

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(VI) Sebaceous glands:

  • Side branches of hair follicle buds
  • Central cells degenerate forming fatty secretions

 

Congenital anomalies:

  1. Ichthyosis – dry scaly skin
  2. Hypertrichosis – excessive hair
  3. Atrichia – congenital absence of hair
  4. Dermoid – cystic swelling along lines of fusion

 

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