Lecture 3 Flashcards
What is the duration of prenatal development (directly after conception as well as directly after fertilization?)
Duration is 40 weeks from conception, usually 38 weeks from fertilization
What are the three zygotic stages of development in order?
- Germinal Period (Period of the zygote)
- Embryonic Period (Period of the embryo)
- Fetal Period (Period of the Fetus)
What marks the end of the germinal period? How long does this usually take?
The implantation of the zygote (0 - 14 days, implantation takes roughly 1 week)
In what zygotic period can the sex of the baby be determined?
The fetal period
What is the role of amniotic fluid?
cushions and helps with temperature regulation
What is the first important developmental structure of the fetus?
The neural tube
What is the order of development in the period of the embryo?
- Neural Tube
- Cardiovascular System
- Face
- Urinary System
- Beginning of Skeletal Development
How fast is an am embryonic baby’s heart rate?
120-180 bpm
What indicates the end of the embryonic period?
All major systems are present, the first bone cells appear, and there is a complete human form
Around which week is the period of the fetus?
9 weeks
What is the role of the period of the fetus?
Rapid growth in body size and complexity
What is the important supplement for women in the embryonic phase for the closure of the neural tube?
Folic Acid
What is the order of eye development in the fetal period?
The eyeballs form -> connect to the brain -> and the fetus is sensitive to light around 16 weeks
What is the focal growth point after the eyes begin to develop?
The limbs lengthen
Describe the 2 steps of brain development
20 weeks:
Neurons are all formed, myelination will begin, cortical cells are forming (folds)
27 weeks:
Synaptogenesis
Myelination
Specialization of lobes
Define synaptogenesis and myelination
Synaptogenesis is the establishment of connections between neurons, and myelination is the deposit of myelin on the nerve axons that insulate and speed up signal transmission
What organs develop after the brain? What two other growth processes are observed during this time?
The skin and lungs.
1. Motor behaviours such as sucking are also observed
2. The fetus gains fat
How is auditory reception tested during pregnancy?
Fetal blinking in response to noise
What are the three reasons for abnormal prenatal development?
- Maternal Environment
- Teratogens
- Genetic issues
What is it called when the zygote implants in he fallopian tubes?
An Ectopic pregnancy
What are the risks associated with a breech birth?
The umbilical cord is compressed or around the neck
What are the leading theories as to why maternal stress impacts fetal development?
- Blood is drawn to the mothers organs instead of development
- Stimulant hormones cross the placenta
- Stress is correlated with other risk factors such as drugs
What is rH factor incompatibility in pregnancy? How is this risk mitigated?
Baby blood causes mom to develop antibodies for following babies. There are vaccines available now to reduce the effect.
What are 4 vitamins essential to prenatal development?
Iron, Folic Acid, Vitamin D, and fatty acids
Define a teratogen
An environmental agent that causes fetal damage during the prenatal period
When do teratogens do the most damage? What developmental period is this?
During sensitive periods such as organogenesis. Teratogens are most potent in the embryonic period.
What are the three types of teratogen?
Disease, Drugs, and Toxins
What 5 diseases are covered in the class?
- Rubella
- STDs
- HIV/AIDS
- Toxoplasmosis
- Malaria
What is significant about Rubella? What is its defining effect?
A high proportion (half) of moms with it had kids with physical birth defects of eyes, heart, intestines, and urinary systems
What are some associated risks with pregnancy with an STD
Risk of ectopic pregnancy, motor development, formation of major systems
How can HIV/AIDS be transmitted to a fetus?
Through placenta or also breast milk
What is the first drug found to be a teratogen?
Thalidomide was taken as a morning sickness pill
What drug is associated with genital/reproductive organ poor development/cancer?
DES
What acne drug is a teratogen?
Accutane
What common drugs are associated with LBW and miscarriage?
Aspirin and Caffeine
What are some effects of FASD?
Cognitive effects:
Mental retardation, poor attention, hyperactivity
Physical Effects:
Facial abnormalities, slow growth
What drugs can leave babies with withdrawal-like symptoms? (low eye contact, not cuddly, irritable)
Cocaine, Heroin, Meth
What is the mechanism of teratogenesis with nicotine? What is a special consequence associated with nicotine?
It causes poor placenta growth which restricts oxygen levels. It is associated with SIDS
What are four environmental toxins? What part of development do they effect mostly?
radiation, lead, PCBs, and Mercury all affect neural development
