The germinal period is
the first 2 weeks of prenatal development after conception
, which involves rapid cell division and the start of cell differentiation. First Stages of the Germinal Period. The original zygote as it divides into two cells, four cells and eight cells.
What happens during the germinal period?
The germinal period (about 14 days in length) lasts from
conception to implantation of the zygote (fertilized egg) in the lining of the uterus
. During this time, the organism begins cell division and growth. After the fourth doubling, differentiation of the cells begins to occur as well.
What stage is the germinal stage?
The germinal stage is
the stage of development that occurs from conception until 2 weeks (implantation)
. Conception occurs when a sperm fertilizes an egg and forms a zygote. A zygote begins as a one-cell structure that is created when a sperm and egg merge.
What is the approximate age of germinal period?
The germinal period (
about 14 days in length
) lasts from conception to implantation of the zygote (fertilized egg) in the lining of the uterus. During this time, the organism begins cell division and growth. After the fourth doubling, differentiation of the cells begins to occur as well.
When is the zygotic period?
The zygote phase is brief, lasting only
about four days
. Around the fifth day, the mass of cells becomes known as a blastocyst.
What are 3 major developments in the germinal period?
The germinal stage involves several different processes that change an egg and sperm first into a zygote, and then into an embryo. The processes include
fertilization, cleavage, blastulation, and implantation
.
Why is the embryonic period the most critical?
The embryonic period is the most critical period of development
because of the formation of internal and external structures
. The critical periods of development for the organs are also discussed in the section on specific organ development.
Which trimester is the most critical for fetal development?
The first trimester
is the most crucial to your baby’s development. During this period, your baby’s body structure and organ systems develop. Most miscarriages and birth defects occur during this period. Your body also undergoes major changes during the first trimester.
What is the longest period of prenatal development?
The longest period of prenatal development is
the fetal period
which begins at the 9th week after conception and lasts until birth. By the 12th week, the genitals have formed. Development of all the structures of the body continues and by the end of the third month, all structures are present although immature.
What is the correct order of prenatal development?
There are three stages of prenatal development:
germinal, embryonic, and fetal
.
What is the critical period of pregnancy?
In general, major defects of the body and internal organs are more likely to occur
between 3 to 12 embryo / fetal weeks
. This is the same as 5 to 14 gestational weeks (weeks since the first day of your last period). This is also referred to as the first trimester.
What are the stages of prenatal period?
The process of prenatal development occurs in three main stages. The first two weeks after conception are known as the germinal stage, the third through the eighth week is known as the embryonic period, and the time from the ninth week until birth is known as
the fetal period
.
What is the pre embryonic period?
The first 2 weeks of prenatal
development are referred to as the pre-embryonic stage. A developing human is referred to as an embryo during weeks 3–8, and a fetus from the ninth week of gestation until birth.
What part of the body grows first in the womb?
Arms and legs
.At first, your baby’s arms and legs begin as little buds that sprout from the embryo’s sides. As they grow, the arms look like paddles and the legs look like flippers. A ridge appears on the end of each one. They eventually become your baby’s fingers and toes.
At what point is an embryo considered a human?
As demonstrated above, the human embryo, who is a human being, begins
at fertilizationónot at implantation (about 5-7 days), 14-days, or 3 weeks
. Thus the embryonic period also begins at fertilization, and ends by the end of the eighth week, when the fetal period begins.
Does an embryo have a heartbeat?
The embryo can move its back and neck. Usually,
heartbeat can be detected by vaginal ultrasound
somewhere between 6 1⁄2 – 7 weeks. The heartbeat may have started around six weeks, although some sources place it even earlier, at around 3 – 4 weeks after conception.
