Lecture 3 - Prenatal Development and Pregnancy Flashcards
What is the importance of prenatal development?
Fastest growth of body and brain, basis for further development
What is conception?
The fusion of 1 egg cell and 1 sperm cell, happens during ovulation
What is a zygote?
Fertilized egg cells
Why is the zygote diploid?
Contains 46 chromosomes, carries the complete genetic material
What is a gamete?
Sperm or egg
Why is the gamete haploid?
Contains 23 chromosomes, half of the genetic material necessary to form an organism
Why are monozygotic twins identical?
They develop form 1 egg cell and 1 sperm cell
Which chromosome is the sex chromosome?
23 - only chromosome not necessary for survival
Explain the (XXY) Klinefelter syndrome?
Affects men.
Long body and limbs, low testosterone, fertility problems.
XXXY or XXXXY forms have lower IQ.
Requires hormone therapy
Explain the (X0) Turner syndrome
Affects females with only 1 X chromosome. Underdeveloped secondary sex characteristics, low estrogen, fertility problems, short body and limbs
Explain Trisomy 21 (aka Down Syndrome)
There are three 21 chromosomes.
Dependent on the age of the mother.
Intellectual disability, short body, lower life expectancy, higher risk of Alzheimer’s
What is chorionic villus sampling (CVS)?
Withdrawal of cells from placenta, increases chance of miscarriage
Nuchal fold thickness
Fluid of the neck > If thicker there is a change for Down syndrome
Which are the phases of prenatal development?
Germinal (0-2), embryonic (3-8), fetal (9-40)
What happens during the germinal phase?
Development into blastocyst. It’s a very sensitive phase, high chance of miscarriage.
What is a blastocyst?
Layered cell mass with a cavity > later forms the embryo
Which are the layers of the blastocyst?
Endoderm, mesoderm, ectoderm
What is the endoderm layer?
Becomes the digestive and respiratory system
What is the mesoderm layer?
Becomes the muscles and skeletal system
What is the ectoderm layer?
Becomes the skin and nervous system
What is organogenesis?
Formation of organs
When does the circulatory system form?
3rd week - baby hooks up to maternal blood system
___ folds into the neural tube
The ectoderm
Which are the 3 principles of prenatal development?
Proximodistal order (from in to out), cephalocaudal order (from top to bottom), mass to specific (from rough to detailed)
Which are the steps of the development of neuronal networks in the fetal phase?
Neurulation, neuronal proliferation, neural migration
What happens during neurolation?
Formation of the neural tube
What happens during neuronal proliferation?
Fast formation of neurons (embryonic and fetal phase)
What happens during neural migration?
Neurons go to the right areas of the brain and begin to form connections
What is the age of viability?
22-23 weeks
Define the term teratogen
Substance that cross the placenta and are harmful influences on the unborn child
When are teratogens most harmful and why?
During the embryonic phase. Because that’s when the organs and brain start to form
When do teratogens affect brain development the most?
2nd and 3rd trimester
Why are teratogens dose dependent?
The more a mother uses a harmful substance, the stronger the effects and higher the risks
The severity of teratogens depend on individual differences. Why?
It depends on fetal and maternal genetic vulnerabilities
What was the harmful effect of Softenon?
Birth of children with missing or underdeveloped limbs
What are the consequences of smoking during pregnancy?
Nicotine constricts blood vessels > reduced blood flow > less nutrition and oxygen
When is nicotine’s effect the strongest during pregnancy?
3rd trimester
What are the consequences of nicotine consumption during pregnancy?
Increased risk of miscarriage, premature birth, asthma, cognitive problems, behavioral regulation problems
