A&P review, embryonic period

OVULATION

oogenesis

formation and development of eggs cells

when does ovulation occur?

14 days before next menstrual period

what does FSH support

follicle and egg maturation

what does the corpus luteum do

temporarily produces hormones that support early pregnancy

what does hCG do

supports the corpus luteum until placenta takes over

FERTILIZATION

how long does the ovum survive after ovulation

12-24 hours

how long does the sperm last

2-3 days

where does fertilization occur

in the outer third of the fallopian tube

where does implantation happen

in the uterus

PRE-EMBYRONIC PERIOD (from zygote to implantation)

what are the steps from zygote to implantation

1. fertilized ovum becomes a zygote

2. divides by mitosis then travels to uterus (3-4 days)

3. progresses through early cell division and the morula stage

4. becomes blastocyst

5. blastocyst implants in the uterus

blastocyst layers

• inner cell mass turns into embryo

• outer cells turns into the placenta and fetal membranes

where does implantation happen

in the decidua (endometrium lining) located in the upper uterus

how many days does implantation happen after conception

6-10 days

what will begin to secrete hCG

chorionic villi

what can cause early pregnancy loss during this time

inadequate hormonal or vascular supply

ECTOPIC PREGNACY

what is an ectopic pregnancy

during pregnancy, implantation happens outside the uterine wall, commonly in the fallopian tube

ectopic pregnancy can be life threatening

what are some risks identified with this kind of pregnancy

• tubal scarring

• STI’s

EMBRYONIC PERIOD

what stage does the embryonic period occur

weeks 3-8

what happens during the embryonic period

cells rapidly differentiate into specialized tissues

major organs and body systems form during this period

why is this period critical

it is critical for birth defects since the embryo is vulnerable to teratogens

vitamins and iron are important to take during this period