During which prenatal stage do organs and major structures develop?

During which prenatal stage do organs and major structures develop?

• A. Germinal stage: zygote forms and implants.
• B. Fetal stage: growth and maturation of organs.
• C. Embryonic stage: organs and major structures develop.
• D. Neonatal stage: birth and adaptation.

Answer: (C)

This question tests when the body's major organs and structures first form. The key idea is organogenesis, the process by which the embryo develops its essential organs and body parts. This happens during the embryonic stage, roughly from the third to the eighth week of gestation, when cells differentiate and organize into the brain, heart, limbs, and other major systems. Before this stage, the germinal period involves fertilization and implantation, not organ formation. After the embryonic stage, the fetal period is about growth and refinement of those already formed organs, not their initial development. The neonatal stage is after birth, involving adaptation to life outside the womb. So, the embryonic stage is the period during which organs and major structures develop.

This question tests when the body's major organs and structures first form. The key idea is organogenesis, the process by which the embryo develops its essential organs and body parts. This happens during the embryonic stage, roughly from the third to the eighth week of gestation, when cells differentiate and organize into the brain, heart, limbs, and other major systems.

Before this stage, the germinal period involves fertilization and implantation, not organ formation. After the embryonic stage, the fetal period is about growth and refinement of those already formed organs, not their initial development. The neonatal stage is after birth, involving adaptation to life outside the womb.

So, the embryonic stage is the period during which organs and major structures develop.