Embriología Humana y Desarrollo Dental

1.1 Introduction

• Embryonic period begins at fertilization and lasts until the formation of a human being.
• Teeth develop until they erupt.
• Temporary and permanent teeth combine during this period.
• Tooth parts develop different morphologies & biting forms (occlusion).
• Each tooth has a name or number based on its classification method.

1.2 Human Embryology

• Studies the prenatal period.

• Prenatal (embryological) development is divided into three stages:

  • Weeks 1-3: Early stage (blastula)
  • Weeks 4-8: Embryonic stage
  • Weeks 9-40: Fetal stage

• Fertilization: Union of a haploid ovum & a haploid spermatozoon in the fallopian tube.

• Results in a diploid cell (zygote) with 46 chromosomes (genetic info from both).

• Zygote division & movement: Moves through the fallopian tubes to the uterus.

• Implantation: Implants in the uterine lining (endometrium).

• Stages of Development:

  • Zygote
  • Morula (12-32 cell sphere)
  • Blastocyst (or blastula)
  • Gastrula

• Blastocyst: Hollow ball of cells with an inner cell mass that creates a cavity (blastocoele) with an outer layer.

• Gastrulation: Invagination process which creates germ layers (ectoderm, mesoderm, endoderm) which develop into body tissues.