Reproductive System - First Trimester Flashcards
How long is the First Trimester?
Week 1-12 AFTER fertilization
What is the amniotic cavity and when does it form?
Amniotic cavity forms the 2nd week of the first trimester, it is a fluid filled space where the embryo will develop. It grows in between the inner cell mass and the trophoblast.
Function of the Amniotic Cavity?
Protects baby from infection, dehydration and impact/changes to the temperature.
What is Gastrulation anad where does it occur?
Gastrulation occurs during the second week, it is a process where the inner cell mass will form 3 layers; Ectoderm, Mesoderm, Endoderm. This marks the stage where the blastocyst will become a gastrula.
What is a gastrula?
An embryo that has 3 germ layers being formed.
What are the three germ layers in charge of?
1.) Ectoderm - Nervous system and sensory organs 2.) Mesoderm - Skeletal, Muscular, Excretory and Reproductive System. 3.) Endoderm - Respiratory and Digestive system
Define differentation?
When stem cells become specialized to adhere to things that need extra cells/supporting the gene expression.
What happens during the third week of the first trimester?
Neurulation: it is the process of the formation of neural tubes, so it can form the spinal cord and brain. Soon after, the heart begins to form! Neurulation begins the development of the organs.
What happens during the fourth week of the first trimester? What are their functions?
The formation of the yolk sac. Yolk sac contributes to the development of the babys blood cells, germ layers that will later become babys gamates, and the development of the digestive system. The yolk sac eventually decreases in size while the amniotic cavity increases.
What happens during week 5 of first trimester?
The development of the placenta as diffusion gets more inadequate as the baby is developing rapidly.
When is the placenta fully developed and its function as well as its location.
Located on the uterine wall. Fully developed at 10 weeks, and its is the site of exchange of nutrients and wastes between mom and baby. (to baby - nutrients and oxygen) (from baby - carbon dioxide + other wastes).
What happens within the 8-9 week of the first trimester?
The development of the umbilicord, which consists of a vein bringing in the nutrients and oxygen from mom to baby and two arteries from baby to mom sending all the waste away.
By week nine.. the embryo is referred to as
A fetus!
When the placenta is fully developed, what happens?
After 2-3 months, hCG stops being secreted, and the corpeus luteum remains in tact throughout the entire pregnancy but once placenta is fully formed,, corpeus luteums hormone secretion declines as the placenta takes its place in secreting estrogen and progesterone.
