Fertilization

Sperm cells undergo in the female reproductive tract to become capable
of fertilization. This involves changes in the acrosomal membrane, increased flagellar activity, and chemotactic activity guided by chemical signals from the egg

Capacitation

Fertilization events normally occur in

upper third of uterine tube

required for fertilization to occur

• Releases enzymes from head to sperm (multiple sperm at different times)

Acrosome reaction

Sperm cells must penetrate the _________ and ________

corona radiata and zona pellucida.

• enzyme allows sperm to break down extracellular matrix of corona radiata [granulosa cell layer]

  • Sperm head can now meet oocyte membrane

Hyaluronidase

The egg cell releases _____ ions to prevent polyspermy and undergoes a final
meiotic division to release the third polar body

calcium

Post-Fertilization Events
-The zygote travels down the uterine tube to the

uterus.

A solid ball of cells.

Morula

An inner cell mass develops within a fluid-filled sphere, which implants
into the uterine lining.

Blastocyst

Women pregnant with twins, first twin was delivered, went back and uterus was empty, where is the other twin?

In the uterus cavity

We hatched out of the

zona pellucida

• _____ hatches out of zona pellucida

  • Allows:

  • Better access to uterine secretions (nutrients)

  • Increased growth

  • Blastocyst implants in specific orientation in uterus

• blastocyst

____ hatches and implants with the embryonic disc facing the uterine wall.

The blastocyst

______ produce the chorion and chorionic villi, contributing to the fetal part of the placenta.

Trophoblasts

______ occurs to form the three germ layers (triploblastic nature of the embryo)

Gastrulation

(formation of the three primary layers, the bulk of our body is from mesoderm)

Gastrulation

Hormone Levels During Implantation:
- Estrogen levels ________l, while progesterone levels _____ to sustain the pregnancy and maintain the functionalis.
- The levels of estrogen and progesterone that is produced helps to (3)

-rise and then fall: increase

-maintain the functionalities, placenta and pregnancy in general.

Outermost cells of blastocyst [syncytiotrophoblast] secrete a hormone called

hCG

human chorionic gonadotropin (hCG) (3)

• Produced only during pregnancy [in urine and blood, basis of pregnancy tests]

• Stimulates corpus luteum to secrete estrogen and progesterone

  • Promotes placental development

• Progesterone suppresses menstruation and maintains uterine lining

Once placenta starts secreting estrogen and progesterone hCG level declines and

remains low

Blood supplies ______, however they connect through the sinus spaces in the functionalis, so that both mother and the fetus has blood support.

do not get mixed

-The membranes lining: (4) are the membranes surrounding the fetus in development.

Amnion, Chorion, Elantois, and Yolk Sac

• outermost embryonic membrane and arose from outer cell layer of blastocyst

• Gives rise to fetal part of placenta

Chorion

• the innermost embryonic membrane

  • Cavity fills with amniotic fluid

Amnion

• is nonfunctional

  • Contributes to umbilical vessels

Allantois

•  is nonnutritive

  • Blood cell production

  • Some cells migrate to gonads

Yolk sac

The amniotic fluid is protected inside the layers, or rather amniotic fluids and amnion is
what houses the water.
-Chorionic helps with circulation with the membrane mentioned above

Placenta

PLacenta: Fetal portion arises from

chorion

Placenta: Fetal side (____) and maternal side (____)

-smooth

-rough

Placental hormones (regulate cycles) (5)

-Human chorionic gonadotropin [hCG]

-Progesterone and estrogen

-Progesterone:

-Estrogen

-Corticotropin-releasing hormone

Pregnancy: The Mother
*Releasing hormone helps to signal: ____
-Pancreas: Insulin levels ___ because its donated to fetus, which increase sugar dependency in the mother herself as well.
-Thyroid _____ the circulation!

-CRH

-rise

- increase

•  produced by chorion so embryonic origin

  • Stimulates corpus luteum (progesterone)

• Stimulates testosterone production fetal testes: surge that is measured

Human chorionic gonadotropin [hCG]

• Stimulates development, maintenance of endometrium

• Stimulates mammary development

Progesterone and estrogen

• Inhibits uterine motility

• Inhibits pituitary secretion of GnRH

Progesterone:

Stimulates mass increase myometrium

Estrogen

Likely involved in determine length of pregnancy and timing of childbirth

Corticotropin-releasing hormone

Hormone levels inside the pregnancy!:
_____ help maintain the function, as well as the thickness of the uterus itself, and the lining!

Pro and Estro

• Maintenace of corpus luteum

• Growth effects on fetus

• Stimulate prostaglandin release

• Decrease maternal use of glucose (could lead to gestational diabetes)

• Increase maternal use of fatty acids

Human chorionic somatomammotropin (hCS)

• secreted by endometrium and corpus luteum

  • Transform pubic symphysis cartilage from rigid to more flexible

  • Relaxes myometrium (prevent expulsion)

  • Stimulates proliferation of blood vessels

Relaxin

• Pancreas – insulin production _____

  • Response to decreased maternal sensitivity (glucose sparing)

-increases

• Adrenal glands – maternal aldosterone level ___

  • Na+ retained

  • H2O retained (obligatory)

  •  Fetal and maternal plasma volume increases

- rises

• Thyroid hormones and metabolism level both _____ in mother

  • Resting pulse pressure increases

  • O2 delivery to fetus increases

• increases

Amniocentesis and chorionic villi sampling