Developmental Stage of the Embryo Notes PDF

Tuesday 14^th^ January 2025 **Developmental Stage of the Embryo** **Germinal Stage:** The germinal stage begins at conception when a sperm and egg join in the fallopian tube. The sperm fertilizes the egg and creates a zygote. The zygote journey down the uterus and divides many times creating two s...

Tuesday 14^th^ January 2025 **Developmental Stage of the Embryo** **Germinal Stage:** The germinal stage begins at conception when a sperm and egg join in the fallopian tube. The sperm fertilizes the egg and creates a zygote. The zygote journey down the uterus and divides many times creating two separate structures. One structure becomes the embryo (and later the fetus) and the other becomes the placenta. Cell division continues, the zygote turns into a blastocyst. The blastocyst arrives at the uterus and implants in the uterine wall. If implantation is successful your body begins to produce hormones to support pregnancy. This stops your menstrual cycle. **Embryonic Stage:** This stage last from about the third week -- 8 week of pregnancy. The blastocyst begins to take human characteristics. It is now called the embryo. Structures and organs like the neural tube (which later becomes the brain and spinal cord) head, eyes, mouth and limbs form. By the end of week eight, most embryo's organs and systems take shape. **Fetal stage:** The fetal stage of development begins around the 9^th^ week and last until birth. This is when the embryo turns into a fetus. The fetus's major organs and body systems continue to grow and mature. Things like fingernails, eyelashes and hair also grow. The fetus is able to move its limbs. The majority of growth - in both weight and length -- happens in the fetal stage.