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Place these in order Placenta forms Zygote divides Fertilization occurs Gastrulation begins Heart forms?
fertilization zygote divides gastrulation placenta forms
Where do the nutrients used by the zygote between fertilization and implantation come from?
The nutrients used by the zygote between fertilization and implantation come from the newly formed placenta. The placenta is what provides nourishment to the developing fetus.
Why internal fertilization often produces fewer offspring than external fertilization?
Internal fertilization utilizes a placenta and womb and this limits the number of offspring that can be produced. Internal fertilization also has a higher birthrate than external fertilization.
Does a squid have a placenta and an umbilical cord?
No, only mammals have a placenta with umbilical chord.
Are twins in the same placenta genetically identical"?
No, twins in the same placenta are not genetically identical. While identical twins share the same DNA, they may have slight genetic differences due to mutations that occur after fertilization.
Where does sperm travel to attach to the wall of the placenta?
Sperm does not travel to the placenta; rather, it fertilizes an egg in the fallopian tube. Once fertilization occurs, the resulting zygote travels to the uterus, where it implants itself into the uterine lining, not the placenta. The placenta develops later as the embryo grows, facilitating nutrient and waste exchange between the mother and the developing fetus.
When is a placenta formed?
The endometrium begins to form shortly after the fertilized egg (blastocyst) implants into the uterine wall (endometrium). This typically occurs 3-4 days after fertilization. After implantation, the endometrium is called the Decidua, and basalis is the portion directly under the blastocyst. The Basalis joins the chorionic villi to make the placenta. APEX~ a few days after fertilization
When does the fetus start getting nutrients from the placenta while in the womb?
The endometrium begins to form shortly after the fertilized egg (blastocyst) implants into the uterine wall (endometrium). This typically occurs 3-4 days after fertilization. After implantation, the endometrium is called the Decidua, and basalis is the portion directly under the blastocyst. The Basalis joins the chorionic villi to make the placenta. APEX~ a few days after fertilization
What happens after a few days of fertilization?
The embryo attaches to the mother
Do lamprey have placenta?
No, lampreys do not have a placenta. They are a type of jawless fish that reproduce by laying eggs, and their young develop outside the mother's body. In contrast to mammals, which have placentas to nourish developing embryos, lampreys rely on external fertilization and do not provide maternal support during gestation.
Do sponge have a placenta?
No, sponges do not have a placenta. Sponges are simple, multicellular organisms that belong to the phylum Porifera and lack complex organ systems, including reproductive structures like a placenta. They reproduce primarily through asexual means or by releasing sperm and eggs into the water for external fertilization. As a result, their reproductive processes are very different from those of more complex animals that do have placentas.
How soon after implantation do hCG levels rise?
HCG stands for "Human Chorionic Gonadotropin", the pregnancy hormone. HCG is being produced by the placenta and enters the blood stream as soon as implantation happens, about one week after fertilization and ovulation, when the embryo implants and the placenta attaches to the uterine lining.
