Assisted Reproduction

-In vitro, Intrafallopian gamete transfer, intracytoplasmic sperm injection, preimplantation and genetic diagnosis

a. In vitrofertilization i. Collect oocytes- women go on superovulatory drugs tocreate more than one eggs ii. Have to use catheter to get them

iii. Combine sperm and egg in test tube, allow them todevelop to 4-8 cell stage or later and then place in uterus for implantation

b. Intrafallopiangamete transfer

i. Collect them and put them back in oviduct together

c. Intracytoplasmicsperm injection

i. Like IVF but inject sperm

d. Preimplantationgenetic diagnosis

i. Collect polar bodies or blastomeres (dividing cells offertilized egg) and analyze genetically

First Week

Cleavage and blastocyst formation

cleavage morula: cell division without intervening growth, get morula which is ball of cells

Compaction: morula cells push against each other and form 2 separate tissue types called trophoblast (outer cell mass that forms placenta) and inner cell mass (forms embryo, yolk sac, amnioitic fluid, called embryoblast)

Forms blastocyst cavity

Occurs when trophoblast and endometrial epithelium make contact

Trophoblasts stimulated to divide and the progeny of these divisions form syncytiotrophoblast (large, multinuclear)

unfused trophoblast cells called cytotrophoblast, continue to divide and fuse with syncytiotrophoblast

Syncytiotrophoblast and implantation (week 2)

invasive (allows organism to burrow in)

surrounds and maintains contact with organism to keep embryo separate from endometrium 

Anti-immune

secretes human chorionic gonadoptropin (prevents menstruation)

morning sickness, abdominal pelvic cramping, vaginal bleeding, high levels of hCG

most likely location is oviducts

therapeutic abortion

Weeks 3-8

Critical period,when most of major organ systems develop in significant way

Exception: nervous system, development throughout life surfactant in lungs immune system and also reproductive system

perturbation=major malformation

Gestationalage: what a physician calls time ofpregnancy

Lasts 40 weeksbecause it includes 2 weeks before ovulation (last date we can remember is thedate of last menstrual cycle (so from last menstrual cycle+ 40 weeks)

Fertilizationage: Embryo takes 38 weeks to developfrom ovulation (which is when fertilization actually happens)

Surgical removal of embryo that is implanted indangerous location (ectopic pregnancy) is called therapeutic abortion Spontaneousabortion is miscarriage, occursnaturally

Induced abortion- mother chooses to induce abortion

G1: 2n Diploid

after S: 4n Diploid

after mitosis: 2 cells, 2n Diploid

Meiosis Chromosomes

Male and female difference

start diploid 2n, replicate to be diploid 4N

Meiosis I, become diploid 2N

Meiosis II become haploid N

Females: frozen in meiosis II, Meiosis II not completed until fertilization, also create large oocyte with 2-3 polar bodies

Sperm burrows through corona radiata and zona pellucida

Sperm binds sperm receptor in zona pellucida and causes sperm to release contents of acrosome (you need a lot of sperms for this)

One fuses with oocyte

Oocyte releases cortical granules, changes conformation to prevent polyspermy

Finishes Meiosis II

begins metabolism

Male and female pronuclei fuse to form zygote

Begin mitosis

Occurs in ampulla of oviduct