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Human sexual reproduction, to produce offspring, begins with fertilization. Successful reproduction typically involves sexual intercourse between a healthy, sexually mature and fertile male and female. [1] During sexual intercourse, sperm cells are ejaculated into the vagina through the penis, resulting in fertilization of an ovum to form a ...
Other cells migrate through the caudal part of the primitive line and form the lateral mesoderm, and those cells migrating by the most caudal part contribute to the extraembryonic mesoderm. [11] [15] The embryonic disc begins flat and round, but eventually elongates to have a wider cephalic part and narrow-shaped caudal end. [10]
Depending on the animal species, the process can occur within the body of the female in internal fertilization, or outside in the case of external fertilization. The fertilized egg cell is known as the zygote. [2] [5] To prevent more than one sperm fertilizing the egg , fast block and slow block to polyspermy are used. Fast block, the membrane ...
Animal reproduction occurs by two modes of action, including both sexual and asexual reproduction. [1] In asexual reproduction the generation of new organisms does not require the fusion sperm with an egg. [1] However, in sexual reproduction new organisms are formed by the fusion of haploid sperm and eggs resulting in what is known as the ...
The human female reproductive system is a series of organs primarily located inside the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vagina, which leads from the vulva , the vaginal opening, to the uterus; the uterus , which ...
The mammalian male reproductive system contains two main divisions, the penis and the testicles, the latter of which are where sperm are produced and usually held in a scrotum. [5] In humans, both of these organs are outside the abdominal cavity , but they can be primarily housed within the abdomen in other animals.
The process begins with fertilization, where an egg released from the ovary of a female is penetrated by a sperm cell from a male. The resulting zygote develops through mitosis and cell differentiation , and the resulting embryo then implants in the uterus , where the embryo continues development through a fetal stage until birth .
In the female, the paramesonephric ducts persist and undergo further development. The portions which lie in the genital cord [citation needed] fuse to form the uterus and vagina. This fusion of the paramesonephric ducts begins in the third month, and the septum formed by their fused medial walls disappears from below upward.