Monday, January 10, 2011

1/10/11- Nick S.

Today in class we took notes on Pregnancy:

Gestation- carrying of developing young within the female reproductive tract

· Humans = 266 days (about 38 weeks)

· After 1 week after conception, the embryo (blastacyst) implants in the endometrial wall of uterus

· Stem cells begin to grow

· Trophoblast- outer cell layer, becomes part of the placenta

· Placenta- organ the provides nourishment and oxygen to the embryo, also gets rid of waste.

There are 4 pieces of life support once the embryo implants itself into the uterus

1) Amnion- this is a fluid filled sac that encloses and protect the embryo

2) Yolk sac- contains no yolk, produces embryos first blood and germ cell

3) Allantois- forms part of the urinary bladder and part of the umbilical cord

4) Chorion- part of the placenta, maintains the high level of Estrogen and Progesterone

· Contains chorionic villi- embryonic blood vessels that are in close contact with maternal blood supply

· Mom`s blood and embryo`s blood DO NOT MIX!

· By Diffusion, oxygen, nutrients, antibodies, virus (german measles) and drugs move from mom to embryo and waste moves from embryo to mom

First Trimester

· 5 weeks old embryo
· ~ 1 month- 7 mm
· Brain and spinal cord
· 4 limbs buds, short tail and gill pouches

· 9 weeks Fetus~ 5.5 cm
· All organs and boys parts
· Can move

Second Trimester

· Ultra sound is around 18 week’s fetus, can show sex or abnormalities
· 16 week fetus~ 6 cm
· 20 week fetus~ 19 week and is 1/2 kg (1 lb)

Third Trimester

· Circulatory and respiratory systems prepare for breathing air
· Rotates head towards cervix
· At birth ave=
o 50 cm (20 in)
o 2.7-4.5 kg (6-10 lb)


· Labor- strong rhythmic contractions of the uterus controlled by hormones
o Estrogen- induces oxytocin receptors
o Oxytocin- causes uterus to contract

· Cervix dilates (0 to ~ 10 cm), ave. 6-12 hours
· Full dilation of cervix to birth, strong contractions, ave. 20-60 minutes, clamp umbilical cord
· Delivery of the placenta (afterbirth)~ 15 minutes after birth

Home work:

Finish stem cell reading and Questions- due Wednesday January 12th

Study for unit 6 test on Thursday January 13th

Study for Finals on Tuesday January 19th

Next scribe is: Carey E.

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