Growth & development of the human foetus

Description

Human fetal development spans approximately 40 weeks, divided into three trimesters. During the first trimester (weeks 1-12), major organ systems form through organogenesis, with the heart beating by week 6. The second trimester (weeks 13-26) involves rapid growth, limb development, and sensory system maturation. The third trimester (weeks 27-40) focuses on organ refinement, particularly lung and brain development, with significant weight gain. Key milestones include neural tube closure (week 4), limb bud formation (week 5), facial feature development (weeks 6-8), and viability outside the womb (around week 24). Birth typically occurs between weeks 37-42.