Pregnancy Flashcards
Pregnancy refers to the events that
Occur from fertilization to birth
Day 1 of pregnancy is the time from
The first period
Fertilization refers to the events that turn the egg into a
Zygote
Oocyte is viable for
12-24 hours
Sperm is viable for
24-48 hours, but can last in the tract for up to 5 days
For fertilization to occur, sperm must be
Capacitated before penetration
Capacitation of sperm occurs when it
Comes across secretions in the tract
Capacitation allows for the weakening of the
Acrosomal membrane
The acrosome is found at the head of the sperm and contains
Hydrolytic enzymes (help for digestion of hole)
What happens during the Acrosomal Reaction?
Acrosomal enzymes break down the linings of the egg by going through corona and binding to zona
Zygote travels down fallopian tube and into the uterus in the span of
5-6 days
Cleavage occurs when
Zygote is on the way to the uterus
What is Cleavage?
Rapid mitotic division without intervening growth
In the single cell stage, the cell is a
Zygote
The Morula is the
Solid ball of blastomeres (3 days)
The Early Blastocyst is when the
Morula hollows out and fills with fluid
How is the Blastocyst that implants in the uterine lining?
It is a sphere of trophoblast cells and inner cell mass
What is the Blastocyst?
Pre-embryo that forms as its getting closer to uterus
Trophoblast cells release a hormone which
Signals ovaries to maintain corpus luteum
Implantation is completed by
12th day post-ovulation
Placentation is the
Formation of the placenta
Placentation is done with the contribution of
Embryonic and maternal material
What is the Placenta’s endocrine function?
It produces hormones to maintain pregnancy, lactation, and childbirth
The Placenta allows for the exchange of
Nutrients, gases, and waste for embryo
Embryonic stage lasts for
8 weeks
The reproductive system develops in what stage?
Embryonic stage
What determines the gender of the embryo?
Region on Y chromosome called the SRY Gene
What happens when the SRY region is activated?
There is a male-developmental pathway
What is Antigen Sensitivity?
A person has external genitalia that is female but internal is more mixed
How does Antigen Sensitivity happen?
XY and producing testosterone, but there are no receptors on cells to respond to that testosterone
Embryo has undifferentiated gonads around
6 weeks
Both testes and ovaries develop from
Common, undifferentiated structures called genital ridges
Primordial stem cells have origin in the
Yolk Sac
During embryonic development, cells migrate from yolk sac to the embryo and settle in
The genital ridge, differentiating between oogonia and spermatogonia
Early Embryonic Development has two sets of ducts:
- Wolffian: Develop into male stuff
- Mullerian: Develop into female
The Mullerian duct is activated when there is
No SRY Gene
What happens when the SRY Gene is activated?
Release of anti-Mullerian hormone which disintegrates Mullerian ducts and promotes development of Wolffian Ducts
Different ducts are precursors to the
Shape of genitalia
What happens at 5 months (fetal stage)?
Genital swelling either develops into scrotum or the labia majora
Androgen Insensitivity Syndrome occurs when there is a
Mutation in the gene for the androgen receptor, so is insensitive to testosterone and other androgens
Fetal Development ranges from
Week 8 until birth
What is significant about Fetal Development?
Organs are in place but they are not developed (Embryo still is not viable)
The first trimester lasts from
6 to 12 weeks
The second trimester lasts from
13 to 28 weeks
The third trimester lasts from
29 to 40 weeks
