Prenatal Development Flashcards
Embryology
the study of prenatal development
Prenatal development begins with ___ and ends with___
pregnancy; the birth of the child
The 9 months of gestation is usually divided into
3-month time spans or trimesters
Prenatal development consists of three distinct successive periods:
- Preimplantation period
- Embryonic period
- Fetal period
_____period make up the first trimester of pregnancy and___ period constitutes the last two trimesters
Preimplantation period and embryonic; Fetal
Each of the structures of the face, neck, and oral cavity has a primordium. What is a Primordium?
the earliest indication of a tissue type or an organ during prenatal development.
Developmental disturbances that involve the orofacial structures as well as other parts of the body can include congenital malformations or birth defects, which are evident at birth. Most of these occur during ____period.
both the preimplantation period and the embryonic aka the first trimester.
Developmental disturbances that occur during the first trimester occurrence
Occurs in 3 out of 100 cases and are one of the leading causes of infant death
What is Amniocentesis (or amniotic fluid test [AFT])?
a prenatal diagnostic procedure to detect chromosomal abnormalities
How is an AFT performed?
Amniotic fluid is removed and its fetal cells are grown for microscopic study of the chromosomes as well as sampled for determination of other fetal complications
AFT is Usually considered in the following situations:
- Older females
- If one or both parents have a chromosomal abnormality or neural tube defect
- When a previous child was affected
- When the parents are carriers of inborn errors of metabolism or X-linked disorders such as hemophilia
As an alternative to AFT, Pregnant women now have the option of getting a new type of prenatal genetic test called
non-invasive prenatal testing (NIPT)
What is NIPT?
a cell-free fetal DNA testing that involves a simple blood draw from the pregnant woman. It Does not pose any risk and Can be performed very early in the pregnancy
Malformations that occur during the first trimester can be due to
genetic factors, such as chromosome abnormalities
environmental agents and factors, called teratogens
Teratogens include
infections, drugs, and radiation
Women of reproductive age should avoid teratogens to
protect the developing infant from possible congenital malformations
Malformations in the face, neck, and oral cavity range
from a serious cleft in the face or palatal region to small deficiencies of the soft palate or developing cysts underneath an otherwise intact old mucosa
Orofacial congenital malformations are usually understandable and traceable to
a specific time in the embryologic development of the individual
The Preimplantation Period Takes place ___
during the first week after conception
What are the Key Events of preimplantation period?
- Fertilization
- Cleavage
- Blastocyst formation
- Implantation
What happens during fertilization of the PIP?
Sperm cell fuses with egg cell (ovum), creating a zygote
What happens during cleavage stage of the PIP?
Zygote undergoes rapid mitotic divisions, creating smaller cells called blastomeres
What happens during blastocyst formation stage of the PIP?
A fluid filled cavity (blastocoel) develops within the cell mass differentiating the cells into two distinct lineages:
* Inner cell mass (ICM): The group of cells inside the blastocyst that will eventually develop into the embryo
* Trophoblast: The outer layer of cells that will form the placenta and help with implantation
What happens during implantation stage of the PIP?
The blastocyst adheres to the uterine lining, establishing a connection with the maternal blood supply