Embryology Flashcards
Prenatal Period
-when is this?
- 38weeks from conception to birth
- gynecology timing has been from LMP to birth therefore refers to 40weeks
At what weeks of gestation is the:
- embyronic period
- fetal period
*Describe whats developing in each period.
Embryonic: first 8 weeks, all major organs are formed.
Fetal period is the remaining 30weeks, organs grow larger and become more complex.
Define:
- ovulation
- fertilization
- zygote
- cell division
ovulation: egg released into peritoneal cavity
fertilization: occurs as egg travels down fallopian tube (while remaining in the fallopian tube)
Zygote: cell that forms when the ova and sperm fuse
cell division: begins immediately as the zygote travels down the fallipian tube and into the uterus.
As the zygote repeatedly divides daughter cells are formed, what are these cells also called?
Blastomeres.
What is the trophoblast?
-layer of cells surrounding the blastocyst cavity containing the inner cell mass(daughter cells) which helps form the placenta.
What day does implantation occur?
zygote travels through fallopian tube for about 4 days, once in uterus it floats for about 3 days before it implants on the 6th day within the uterine wall.
Why is it so important that women trying to get pregnant take folic acid?
-to ensure closure of the neural tube, we dont want any spina bifida..
What parts of the body are derived from…
- ectoderm
- endoderm
- mesoderm
Ectoderm: epidermis, hair, nails, glands of skin. Brain and spinal cord. Neural Crest: sensory nerve cells, some nervous structures, pigment cells, portions of skeleton, blood vessels in head and neck.
Endoderm: epithelial lining and glands of digestive and resp tracts.
Mesoderm: Nucleus pulposus of intervertebral discs, vertabrae & ribs, trunk and limb musculature, kidneys, gonads.
*mesoderm is freely moveable tissue.
At what day does the heart start pumping?
Day 29!
What is organogenesis? What is prohibited during this time period to promote healthy development?
Organogenesis is weeks 3-8, this is the period when MOST gross structural birth defects are induced. Drugs early in pregnancy are prohibited– may causee many birth defects..
