Life Before Birth

Question 1

Derivatives of the Ectoderm

Answer 1

• Epidermis of skin and its derivatives (sweat glands, hair follicles)
• Epithelial lining of mouth and anus
• Tooth enamel
• Cornea and lens of the eye

Question 2

Derivatives of the Mesoderm

Answer 2

• Notochord
• Skeletal system
• Muscular system
• Excretory sustem
• Circulatory & lymphatic system
• Dermis of skin
• Reproductive system (except germ cells)

Question 3

Derivatives of the Endoderm

Answer 3

• The endoderm ends up being in the middle of the embryo and so makes all the ‘insidey bits’
• Epithelial lining of the digestive tract
• Epithelial lining of the respiratory system
• Lining of urethra, urinary bladder and reproductive system.

Question 4

List the three developmental stages of life before birth and give their timings

Answer 4

Preimplantation: Week 1
Embryonic Stage (Organogenesis): Weeks 2-8
Fetal Stage (Growth and development): Weeks 9-38