This union marks the beginning of the prenatal period, which in humans encompasses three distinct stages: (1) the pre-embryonic stage, the first two weeks of development, which is a period of cell division and initial differentiation (cell maturation), (2) the embryonic period, or period of organogenesis, which lasts ...
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 .
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 critical periods in prenatal development?
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 3 environmental factors that affect prenatal development?
Other teratogens that affect prenatal development include radiation, pollution, and infectious disease . Radiation increases the risk of childhood cancer, as well as emotional and behavioral disorders; because of this, it is recommended that pregnant women avoid x-rays unless absolutely necessary.
What are the 3 stages of zygote?
This period is generally divided into three stages: the germinal stage, the embryonic stage, and the fetal stage . The two-week period after conception is called the germinal stage. Conception occurs when a sperm cell combines with an egg cell to form a zygote.
What are the 5 stages of conception?
- Conception: From Egg to Embryo. ...
- Ovulation. ...
- Moving Into the Fallopian Tube. ...
- The Sperm’s Long Journey. ...
- Fertilization: Sperm Penetrates Egg. ...
- The Cells Start to Divide. ...
- Implantation. ...
- Pregnancy Hormones.
Which is the first period of prenatal 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.
What is the embryo period?
After conception, your baby begins a period of dramatic change known as the embryonic stage. This stage runs from the 5th through the 10th week of pregnancy . During this stage, the baby is called an embryo.
What are the 4 stages of embryonic development?
- 1.1 Fertilization.
- 1.2 Cleavage.
- 1.3 Blastulation.
- 1.4 Implantation.
- 1.5 Embryonic disc.
Which period of prenatal development is the most critical and why?
The embryonic period is the most critical period of development because of the formation of internal and external structures.
What are the developmental stages?
There are three broad stages of development: early childhood, middle childhood, and adolescence . They are defined by the primary tasks of development in each stage.
What are the different stages of prenatal development?
There are three stages of prenatal development: germinal, embryonic, and fetal .
What are prenatal factors?
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.
What are 3 examples of teratogens?
Common teratogens include some medications, recreational drugs, tobacco products, chemicals, alcohol, certain infections , and in some cases, uncontrolled health problems in the birthing parent. Alcohol is a well-known teratogen that can cause harmful effects on the fetus after exposure at any time during pregnancy.
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 is the duration of prenatal stage in days?
This period begins once the organism is implanted in the uterine wall. It lasts from the third through the eighth week after conception . During this period, cells continue to differentiate and at 22 days after conception the neural tube forms which will become the brain and spinal column.
What do you mean by prenatal stage?
Prenatal development (from Latin natalis ‘relating to birth’) includes the development of the embryo and of the foetus during a viviparous animal’s gestation . Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal development until birth.
Which is the third stage of development preliminary to beginning of new life?
There are three stages of prenatal development: germinal, embryonic, and fetal . Let’s take a look at what happens to the developing baby in each of these stages.
What are the 4 stages of embryonic development quizlet?
- Cleavage. 1st stage. ...
- blastulation. 2nd stage. ...
- gastrulation. 3rd stage. ...
- neurulation. 4th stage. ...
- neural tube. Fetal tissue that develops into the central nervous system.
- morula. When the embryo is 16 to 32 cells. ...
- hCG. HUMAN CHORIONIC GONADOTROPIN–hormone produced by placenta. ...
- Zygote.
When does the prenatal period begin quizlet?
The embryonic period of prenatal development occurs from week 3 until week 8 .
What are the three stages in the growth period quizlet?
Terms in this set (18)
This period is generally divided into three stages: the germinal stage, the embryonic stage, and the fetal stage .
What is the first 12 weeks of pregnancy called?
The first trimester is the time in between fertilization of the egg by the sperm (conception) and week 12 of a pregnancy. A woman’s body goes through many changes during the first 12 weeks of a pregnancy.
What development happens in the third trimester?
During the third trimester, your fetus continues to grow in size and weight . The lungs are still maturing, and the fetus begins to position itself head down. By the end of the third trimester, the fetus is about 19 to 21 inches long and weighs, on average, 6 to 9 pounds.
What are the main periods of development that were discussed in the introduction reading?
- Stage 1: The Emergent Pre-reader (typically between 6 months to 6 years old) (back to top) ...
- Stage 2: The Novice Reader (typically between 6 to 7 years old) (back to top) ...
- Stage 3: The Decoding Reader (typically between 7 – 9 years old) (back to top)
What is Stage 3 of the four stages of writing development that children go through from 18 months to three years?
Answer: The stage 3 of the four stages of writing development that children go through from 18 months to three years is Pictures of objects and people interspersed with writing marks . Hence answer is 4. Pictures of objects and people interspersed with writing marks.
What are the ages and stages of development?
Other scholars describe six stages of child development that include newborns, infants, toddlers, preschool, school age, and adolescents . Failing to reach some of the milestones may signal a developmental disability.
