Early Pregnancy Flashcards
What does syngamy mean?
Fusion of male and female pronuclei
What does is an Ootid?
Large single cell comprising male and female pronuclei after fertilization
What is a Zygote?
Product of a fertilized oocyte from haploid gametes to a diploid cell (single cell embryo that eventually divides)
What is an embryo?
Early stage of development following zygotic cellular cleavage
What are Blastomeres?
Individual cells within and embryo as a result of an embryonic cleavage
What is the Morula?
An embryo that contains a minimum of 8 cells but has only one totipotent cell type
What are blastocyst?
Stage of embryo development identified by a blastocele cavity and two distrinct cell lineages
What is the fetus?
Stage of advanced embryo development when the embryo begins to form recognizable structures
What is Conceptus?
Structures that make up the product of conception that are stage dependent and include the embryo, extraembryonic membranes, fetus, and placenta.
How does the process of Preattachment development of the embryo go?
Goes from ootid-> through syngramy-> to Zygote-> 2-celled embryo-> turns to Morula (4-8 cells) -> goes to Early blastocyst-> Hatching Blastocyst-> Hatched blastocyst.
What is cleavage?
1.Increases # of cell
2.Increases cell mass
3.forms blastomeres
What occurs with inner cells?
- They develop gap junctions
- Groups of cells form
What do outer cells do?
Cell to cell adhesions called tight junctions. (alters permeability of outer cells-> fluid accumulation)
Where are tight junctions?
They are between outside cells
Where are gap junctions?
They are between inside cells
What do outter cells pump? What occurs when they pump this substance?
- Outer cells pump Na+ into the embryo
- H2O accumulation
What 2 cell populations are in the blastocyst?
- Inner cell mass -> Embryo proper (fetus)
- Trophoblast -> Chorion (outer placental layer)
What is the Blastocoele?
Fluid filled cavity
What is Hatching?
Blastocyst leaves protective zona
When it comes to the hatching of the blastocyst what 3 forces is it governed by?
- Blastocyst growth & fluid accumulation: increases pressure
- Enzyme production by trophoblastic cells : weaknes zona
- Blastocyst contraction: Intermittent pressure pulses
How does the timeline of bovine embryo development and elongation occur?
- Day 1 cell
- After 3 days turns into 8-16 cell (embryonic genome activation) consists of totipotent cells
- After 5 days the D5 Morula forms
- After Day 7 it turns into a D7 Blastocyst.