Educational Content ,From Fertilization To Childbirth | 3d medical animation | by Dandelion Team
Summary
Highlights
Sperm navigate through cervical mucus to reach the aular isthmic junction of the fallopian tube, where the egg awaits. This challenging journey ensures only the healthiest sperm survive to fertilize the egg. Sperm can survive up to 5 days in the female reproductive tract.
The sperm first penetrates the corona radiata and then binds to the zona pellucida. The acrosome releases enzymes, allowing the sperm to fuse with the egg plasma membrane. This fusion prevents other sperm from entering.
Once fused, the sperm's nucleus enters the egg, combining genetic material to form a zygote with a full set of 23 chromosome pairs. This blueprint instantly determines gender, hair color, eye color, and other characteristics.
The zygote rapidly divides and travels down the fallopian tube, transforming into a 16-cell blastocyst approximately 5-6 days after fertilization. Only 20-30% of fertilized eggs reach this stage.
The blastocyst hatches from its shell and burrows into the uterine wall (endometrium) for oxygen and nutrients. Around four weeks after the last period, the blastocyst produces pregnancy hormones, signalling the ovaries to stop releasing eggs, and is now called an embryo.
By week 5, the circulatory system, brain, and spinal cord begin to form, and the heart starts beating. The placenta forms to provide nutrients and remove waste. By week 6, facial features begin to take shape. Weeks 7 and 8 see significant growth, and tiny hands and feet develop.
From week 9 to 12, the embryo is called a fetus. Most critical development is complete, facial features are more recognizable, and the diaphragm muscles begin to grow. Reproductive, circulatory, and urinary systems are advanced. Fetal urination in the amniotic sac indicates proper function. By week 12, a female fetus's ovaries contain millions of eggs, and a male fetus's testicles produce testosterone. The fetus is about 5 cm in size and weighs 14 grams, continuing to grow and mature until birth.