Mod 3 - Embryology & Development - Part 1

Ampulla

site of fertilization

secondary oocyte

Hasn't fully finished meiosis where later gets formed into a zygote when fertilized

3 prenatal development periods

germinal, embryonic, fetal

Germinal period

The first two weeks of prenatal development, cells multiply and formation of germ layers

embryonic period

Week 3-8, organ systems develop (most important)

Fetal period

9th week to birth, organ systems grow and mature

Clinical timing

date since last menstrual period

Embryologist timing

Starts post-ovulatory (14 days less than clinical age)

What stops multiple sperm from fertilizing the oocyte?

fast and slow block to polyspermy

Fast block to polyspermy

depolarization

slow block to polyspermy

Exocytosis, oocyte shrinks and zona pellucida denatures

zona pellucida

A thick, transparent coating rich in glycoproteins that surrounds an oocyte.

corona radiata

Extra protection made up of follicular cells

acrosomal reaction

When acrosome of sperm binds to receptor leading to the digestion of zona pellucida

Morula

ball of 12+ cells

Implantation

burrowing of blastocyst into uterine wall

Placenta

Exchange of nutrients and waste between mother and embryo

Syncytiotrophoblast

multinucleated cell that invades endometrium wall

Cytotrophoblast

remains close to embryonic tissue and later forms protective cord between maternal and embryonic blood

lacunae

syncytiotrophoblast surround material blood vessels and digest their walls forming pools of blood

chorion

division between maternal blood supply and fetal blood supply

umbilical arteries

away from heart/fetus

umbilical veins

toward heart/fetus