From beginning as a one-cell structure to your birth, your prenatal development occurred in an orderly and delicate sequence. There are three stages of prenatal development:
germinal, embryonic, and fetal
.
What is the second stage of prenatal development?
Embryonic Stage
. The second stage of gestation, the embryonic stage, lasts from the implantation of the blastocyst on the uterine wall until approximately the eighth week of pregnancy. During this time, the embryo’s cells continue to multiply and begin to differentiate to form various body tissues and organs [3].
What are the three prenatal stages of development?
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
.
Which is the longest of the 3 prenatal stages?
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 are the stages of embryonic development?
- Germinal stage. 1.1 Fertilization. 1.2 Cleavage. 1.3 Blastulation. 1.4 Implantation. 1.5 Embryonic disc.
- Gastrulation.
- Neurulation.
- Development of organs and organ systems.
What is the most important stage of prenatal development?
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 period of prenatal development is the most critical?
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 factors that affect prenatal development?
Prenatal risk factors include
chronic maternal illness, certain maternal infections, toxin exposures and nutritional deficiencies
. Risk factors in the perinatal period include pregnancy-related complications, prematurity and low birth weight, and infection exposure during pregnancy or at time of birth.
When does a fetus have a heartbeat?
When does a baby have a heartbeat? A baby’s heartbeat can be detected by transvaginal ultrasound
as early as 3 to 4 weeks after conception
, or 5 to 6 weeks after the first day of the last menstrual period. This early embryonic heartbeat is fast, often about 160-180 beats per minutes, twice as fast as us adults’!
At what week during pregnancy do brain waves form?
The early signs of a brain have begun to form. Even though the fetus is now developing areas that will become specific sections of the brain, not until the
end of week 5 and into week 6
(usually around forty to forty-three days) does the first electrical brain activity begin to occur.
What is the longest stage of pregnancy?
In the
fetal stage
, the developing human organism is called a fetus. This is the longest stage, starting in the ninth week after conception and continuing until birth.
Which stage is the longest stage of labor?
The first stage of labor
is the longest stage, especially if you are giving birth for the first time, and can last anywhere from days to a few hours. Early labor usually takes the longest amount of time and transition the shortest.
What is 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 the first week after conception, the zygote divides and multiplies, going from a one-cell structure to two cells, then four cells, then eight cells, and so on.
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.
What is the final stage of embryo?
By the twelfth week of fertilization the embryo moves into the final stage of development called
the fetal stage
. By now, the fetus has formed all of the organs and structures necessary for a baby, but those organs still need to grow and develop.
What is the first stage of an embryo?
The initial growth stages of multi-cellular organisms start with a zygote cell, which then undergoes fast cell division to form the initial cell cluster, or ‘
blastula
‘. This rapid division of cells is known as the process of ‘cleavage’.
