Week 7: Menstrual Cycle & Conception

Hormones that the ovaries produce

estrogen and progesterone

Number of oocytes that reach maturity

Follicle Stimulating Hormone (FSH)

Responsible for development of select few follicle each cycle

Produced in anterior pituitary

Little amount in system as menstruations begins

Luteinizing hormone (LH)

Surges & leads to ovulation

produced in anterior pituatitary

GnRH

Produce in hypothalamus

Signals ant pituitary to begin producing LH and FSH

Estradiol

Most potent form of estrogen

Estrogen

Responsible for maturing eggs & uterine lining, and developing fertile-quality cervical fluid

Progesterone

Heat-producing

Produced in corpus luteum

Nurtures and maintains endometrial lining of the uterus during post-ovulatory phase

Maintains pregnancy

Cycle day 1

First day of menstruation

NO KEY HORMONES PRESENT IN LARGE AMOUNTS

Pituitary gland is secreting small and increasing amounts of FSH

Cycle day 5

Pituitary begins small amounts of LH - positive feedback from production of FSH

LH helps develop coating of granulosa cells --> secrete estrogen

Estrogen --> signals production of GnRH --> signals production of LH --> follicles continue developing & maturing

Cycle Day 7

Dominant follicle --> more estrogen --> slows down GnRH & proliferative phase of uterus begins

Amt of estrogen produced by dominant follicle continues to rise dramtically

Cycle Day 12

Increased estrogen decreases FSH and LH production

Estrogen amount reaches a peak

LH abruptly surges abt 12-16 hrs before ovulation

Cycle Day 13

LH surg --> FSH surges

Shut down estrogen production in dominant follicle

Cycle Day 14

Ovulation

Dominant follicle swells --> weakening follicular walls

Leftover granulosa cells are transformed into luteinizing cells and then form the corpus luteum which then produces progesterone (results in noticeable increase in temp)

Cycle days 15-26

Corpus luteum produces large amounts of progesterone (and small amts of estrogen)

Continues buildup of endometrial lining for possible pregnancy

Without HCG --> corpus luteum shuts down, dissolves, and stops producing progesterone

If pregnancy then...

Developing embryo produces HCG and corpus luteum continues to release progesterone

Cycle day 27

Dramatic decrease in progesterone

Triggers production of FSH and LH to start again in preparation for next cucle

Menstrual Phase

Days 1-6

Menstruation

Estrogen & Progesterone levels are low

FSH rises

Proliferative Phase

Days 7-14

Cervical mucous is favorable - thin clear, watery & alkaline (Spinnbarkheit)

Cervix rise, opens slightly, soften

Blood vessels dilate, endometrium thickens

At ovulation, body temp drops then rises sharply d/t progesterone

Secretory Phase

Days 15-26

Corpus luteum secretes large amounts of progesterone

Estrogen levels fall

Cervical disappeared

Ischemic Phase

Days 27-28

Corpus luteum degenerates, estrogen & progesterone levels fall

Small blood vessels rupture , spinal arteries contract-causing deficiency of blood in endometrium

Follcular Phase

Days 1 to 14

Maturation controlled by FSH and LH

Mittelschmerz (feeling of ovulation)

Luteal Phase

Days 15-28

Begins when ovum leaves follicle

If fertilized, ovum implants in endometrium and secretes HCG

If unfertilized, it degenerates & stops producing estrogen & progesterone

Most ideal days for intercourse

Days 10-13

Combined Oral Contraceptives

Estrogen & Progesterone

Works on hypothalamus by decreasing amount of GnRH produced -- reduces production of FSH and LH -- no ovulation occurs

Estrogen works to stabilize endometrium and prevents mid-cycle bleeding

Progesterone only pills

No estrogen

Does not reliably prevent ovulation

More risk of breakthrough bleeding w/o estrogen

Usually for women who can't have estrogen

Now an OTC pill!

Hormonal IUD

Slowly releases synthetic form of progesterone into the uterus

Makes endometrium less sensitive to estrogen, so the lining thins

Thickens cervical mucuous

Depo-provera

IM injection of progestin (every 3 months

Prevents ovulation in most women, thickens cervical mucous to prevent fertilization

Basal Body Temperature

Temp increases right after ovulation d/t ovulation & dip right before

If pregnant, temp stays elevated and if not, temp returns to baseline

Can help prevent or cause pregnancy

Uterine Cycle Phases

Menstrual Phase

Proliferative Phase

Secretory Phase

Ishcemic Phase

Ovarian Cycle Phases

Follicular phase

Luteal phase

Mitosis

Occurs in Diploid cells

One-stage divisionq

Autosomes

22 pairs similar cells & 1 pair of sex cells

Meiosis

Diploid cells give rise to haploid cells

2 stages

Oogenesis

Egg production

Meiosis I occurs in female fetus

First meiotic division occurs at ovulation

Second meiotic division occurs at fertilization (producing an ovum & another polar body)

Original polar body divides into 2 polar bodies

Result = 1 haploid ovum & 3 polar bodies

Ovum

Cell surrounded by:

- Zona pellucida

- Corona radiata

Spermatogenesis

production of sperm

spermatogonium replicates and forms 2 haploid cells

Capacitation

Removal of protective coating from heads of sperm

Small perforations form in the acrosome

Acrosomal reaction

Allows for escape of enzymes which are needed for the sperm to penetrate the ovum

Cleavage

Rapid mitotic division form a solid ball of cells eventually creating

- blastocysts

- trophoblast

- morula

When does implantation occurs

7-10 days after fertilization

Germinal stage

0-2 weeks

Embryonic stage

3-8 weeks

Fetal stage

9 weeks - birth

Which structure produces hCG

placenta

can be detected as early as 10 days after conception

Which hormone do ovulation kits test for?

LH - specifically the LH surge

Chorion

Outermost layer of fetal membrane

Chorionic villi

Smooth surface by 4 months

Amnion

Inner layer of fetal membrane

Amniotic fluid functions

Cushion against mechanical injury

Controls temp

Permits symmetric growth

Allows umbilical cord free of compression

Acts as wedge during weath

Provides fluid for analysis

Oligohydramnios

too little amniotic fluid

Polyhydramnios

excessive amniotic fluid

Abnormal amniotic fluid amounts can be a sign of

Renal insufficiency

TORCH diseases

Decidua basalis

maternal portion of placenta

"dirty duncan"

Fetal side of placenta

Covered by amnion

"Shiny schultz"

Umbilical arteries

After circulating fetus

Blood returns to placenta

De-oxygenated

Umbilical vein

Before circulating fetus

Oxyegnated

Embryonic development week 4

Heart beating at about 110 beats per minute

Embryonic development week 8

Clearly resembles human being

Circulation improving

Embryonic development week 12

Well differentiated genitalia & may be able to be seen on U/S

Embryonic development week 16

Fetal movement! (quickening)

Lanugo begins to be developed

Embryonic development week 20

First anatomy U/S & gender reveal

Skin less transparent

Embryonic development week 24

Age of viability

hand creases

Embryonic development weeks 25-28

Brain developing rapidly

Embryonic development weeks 29-32

Weight gain is from incr body muscle & fat

Embryonic development week 35-26

Late pre-term

5-6 lbs

Firm grasp

Embryonic development weeks 38-40

Males usually larger

skin is smooth

head is larger than chest

fetus fills uterine cavity

has own body rythms

Trophoblast develops into

placenta

Karyotype

Pictorial analysis of an individuals chromosomes

Down Syndrome

Trisomy 21

47 chromosomes

Trisomy 18

Edward's syndorme

Trisomy 13

Patau Syndrome

Turner Syndrome

One X chromosomes

Short height

Underdeveloped ovaries

Heart defects

Wide web-like neck

Klinefelter syndrome

XXY

Underdeveloped testes

Low sperm production

Decreased testosterone & muscle mass

Sparse body hair

Autosomal dominant disorders

Huntington disease, achondroplasia, neurofibromatosis, BRCA1 and BRCA2

Autosomal recessive disorders

CF

Sickle cell disease

Phenylketonuria

Tay-sachs

Dizygotic twins

Fraternal

genetic predisposition

two placentas, chorions, amnions

Monozygotic twins

Identical twins

Number of amnions and chorions depends on division

Two placentas most of the time

Mono/Mon twins - very dangerous - twisting of cords

X-linked recessive disorders

color blindness, hemophilia, duchenne muscular dystrophy

Maternal Fetal Medicine (MFM)

Medical specialty of Perinatology

Care for women planning or experiencing high-risk pregnancy

Pt: Advanced maternal age, DM, HTN, genetics concerns, etc.

Maternal Alpha-Fetoprotein (AFP)

15-22 weeks

laboratory test used to assess for neural tube defects or chromosome disorders

has high rate of false positives --> will then get diagnostic testing

Cell-free Fetal DNA

Maternal serum blood test that extracts fetal DNA from maternal circulation with a 98% detection rate for fetal Trisomy 13 Trisomy 18 and trisomy 21

9-10 weeks

Limited coverage esp. if under 35

Amniocentesis

U/S guided needle to test for genetic abnormalities, lung maturity, and neural tube defects

Small risk of miscarriage

Chorionic Villus Sampling (CVS)

Bx of placental tissue

Performed by MFM through TV U/S guided needle

10-13 weeks

Small risk of miscarriage