The document discusses the early stages of human development from fertilization to the third week of gestation. It describes the formation of the three germ layers - ectoderm, mesoderm and endoderm - and the tissues they give rise to. It then focuses on eye development, explaining how contact between the neural ectoderm and surface ectoderm leads to the invagination of the lens placode and optic vesicle. This forms the lens vesicle and bi-layered optic cup, with the optic cup remaining connected to the forebrain via the optic stalk. Retina formation is also mentioned.

1. Chakri@Psb
Sr. Optometrist

2. SPERM-to-OVUM

3. SPERM-to-OVUM

5. Fertilization to 3rd Week Gestation Period

6. 3 Germ Layers
ECTODERM: (Gives rise to the)
*Central nervous system (the brain
and spinal cord)
*Peripheral nervous system
MESODERM:
Connective Tissue
Cartilage
Heart Walls, Blood And Lymph
Vessels Cells
Bone
ENDODERM:
*Epithelial lining of the GI and
*Respiratory
*Liver
*Thyroid

14. Formation of Both eyes Eyes

15. Contact Between Neural ectoderm & Surface Ectoderm

16. Invaginating of Lens PLACODE & OPTIC VESICLE
• Lens Placode forms the Lens Vesicle (that pinches off the
surface ectoderm)
• Optic Vesicle forms the Bi-layered Optic Cup that
remains connected to the FOREBRAIN via the Optic Stalk

18. Retina Formation

20. Chakri@Psb
Sr. Optometrist