Week 2. first week of development Flashcards Preview

Developmental Bio > Week 2. first week of development > Flashcards

Flashcards in Week 2. first week of development Deck (20):
1

ovarian cycle

Under control of many hormones
Hypothalamus makes gonadotropin
Makes FH and LH
Under influence of gonadotropins, you have 10-12 follicles that are starting to grow, from single layer to multilayer, then from primary to cedonary
FSH is constantly increasing, then there is a LH surge- induces ovulation and mature oocyte is released

2

hormonal control of ovarian function

Gonadotropin-releasing hormone (GnRH): hypothalamus
Follicle-stimulating hormone (FSH) & Luteinizing hormone (LH): anterior pituitary under the stimulation of GnRH
Estrogen: granulosa and thecal cells

Proliferation of endometrium
Thinning of the cervical mucus
Stimulate pituitary to secrete LH
LH surge at mid-cycle-> ovulation
Stimulate progesterone production

3

ovulation

LH surge causes completion of Meiosis I (preovulatory follicle)
arrested i metaphase of meiosis II (3 hrs before ovulation)
ovarian surface- increase LH-> collagenase increase-> digests fibers around the follicle
LH inc-> prostaglandin-> muscular contraction

4

corpus luteum

secretes progesterone to prevent endometrial shedding and prep for implantation
lutean cells: granulosa, theca cells

5

oocyte transport

fimbriae and cilia move it, 3-4 days to uterine lumen
fertilization occurs at ampulla of the uterine tube

6

fate of corpus luteum

if no fert occurs, the corpus luteum cells die and progesterone stops, so menstruation happens
if fertilized: hCG secreted by syncytiotrophoblast
progesterone produced until end of 4 month

7

Capacitation

maturation of sperm in female reproductive tract- removes glycoproteins and seminal plasma proteins (impt for IVF)

8

acrosome reaction

release of enzyme by sperm to dissolve zona pellucida (ZP)

9

fertilization

phase 1- penetration of corona radiate
phase 2- penetration of zona pellucid
phase 3- fusion of the oocyte and sperm cell membranes

10

fertilization- detailed

Acrosome reaction begins when the sperm hits the corona radiata, prevent polyspermy
Sperm contribute genetic and epigenetic material which is really important
If you keep the father’s mitochondria, it causes problems
Once the sperm enters, the sperm head decondenses and all of the components spill out. All of the components of the sperm (mitochondria) start to disappear
Maternal lysosome destroys that stuff
Paternal protenine is really good at packing DNA
Oocyte never gets the chance to be truly haploid bc it has a maternal pronucleus
oocyte completes meiosis 2
egg activated

11

timing of fertilization

1. sperm deposited in vagina (250,000,000)
2. 100,000 reach uterine cavity
3. 50 or less arrive at distal end of fallopian tube
4. delay at ampullary-isthmic junction where fertilization occurs (1-2 days)

12

timing of implantation

5. delay at utero-tubal junction (days 2-3)
6. egg enters uterine cavity (3-4)
7. blastocyst implants (day 7)

13

blastomere

2-4-88 cells stages

14

compaction

first loose cells-> compacted cells-> segregation of inner and outer cells

15

morula

day 3- 16 dells, inner cell mass: embryo proper makes tissues
outer cell mass: trophoblast- placenta

16

blastocyst

ZP degenerates, uterine fluid penetration, blastoceole cavity forms
cells differentiate into two layers based on epigenetics
inner cell mass- embryoblast
outer cell mass- trophobast

17

uterine cycle

proliferative phase: end of menstrual phase- estrogen regulated
progestational phase- 2-3 days after ovulation, corpus luteum, progesterone
menstrual phase: basal layer of endometrium remains for regeneration

18

implantation

timing: progestational phase
along anterior or posterior wall
three layers in endometrium- compact, spongy, basal

19

infertility

incidence: 15-30%
males and females are both 50% the cause
male: defect in sperm production or anatomical defects
females: defect in oocyte production, amatomical defets, sperm antibody

20

Assisted reproduction technology

IVF
intrauterine insemination (IUI)
intracytoplasmic sperm injection (ICSI)
preimplantation genetic diagnosis (PGD)
cloning: nuclear factor