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Female Reproduction

I).  Divisions

A).  Oogenesis:

B).  Ovarian cycle:

C).  Uterine cycle:

D).  Pregnancy:

II).  Oogenesis

Creation of ovum begins before a girl is born.

Oogenesis results in the creation of only one gamete.

In the fetus

        Meiosis I begins

Duplication and crossing over occurs and Meiosis I stops

 

In childhood

Oocytes are inactive

 

In puberty

i.  Primary oocyte continues Meiosis I dividing into a secondary oocyte and a polar body

ii. OVULATION OCCURS and the follicle undergoes changes

Fertilization occurs

Secondary oocyte completes Meiosis II resulting in an ovum and a second polar body.

Ovum can than be fertilized

Potential products are 1 ovum and 3 polar bodies

 

Summary

1). Fetus

i). fetal cortical (outer) region of the ovaries

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ii).  primordial follicle (primary follicles) with primary oocytes

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iii). Meiosis I begins:

(duplication & crossing over occur)

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iv).  Meiosis I  stops

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2).  Childhood

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3). Puberty

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i). Primary oocyte continues the last stages of meiosis.

Meiosis results in a small polar body and a secondary oocyte

OVULATION OCCURS

ii). The secondary oocyte is ovulated and follicle undergoes changes

(it has not completed meiosis)

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4). IF fertilization occurs

If it is fertilized Meiosis II will continue.

i).  The secondary oocyte will under go Meiosis II before the chromosomes of the male can join to the chromosomes of the female.

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ii).  The result will be an ovum and a polar body.

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iii).  The ovum can than be fertilized.

Polar bodies only contain DNA the secondary oocyte maintains all of the cytoplasm and organelles

III).  Ovarian Cycle

A). Ovarian cycle:

 average 28 days.

Several follicles will start this process at the same time.

B).  Stage

1). Follicular phase: Day 1 to 14

i). primordial follicle– primary follicle

ii). primary follicle– secondary follicle

Theca follici develop

granulosa cells and theca follici produce estrogen

Zona pellucida forms

 

iii). secondary follicle – vesticular follicle

bulges from the ovary

The primary oocyte finishes meiosis I (that was started as a fetus) and it becomes the secondary oocyte with a polar body.

2). Ovulation:

• progesterone
• estrogen

 

IV).  Uterine Cycle

changes that the endometrium undergoes

A). Uterine (Menstrual) Cycle

B).  wall of the uterus

• Endometrium: inner
• Myometrium: middle
• Perimetrium: outer

 

C).  Stages

i). Menstrual phase (Days 1-5)

 

ii). Proliferative phase (Days 6-14)

iii). Secretory Phase (Days 15-28)

 

V). Hormonal Control of Female Reproduction

A). Life stages:

i). Childhood:

 

ii). Prepubescent:

 

iii). Puberty

 

iv). Menopause:

 

B). Hormonal interactions

( ­ arrows point to increasing and decreasing hormone levels.  Some computers do not pick up the arrows and they show as different symbols)

 

Starting on Day 1:

Uterine wall detaches:

Estrogen at lowest level but:

Hypothalamus:

­ GnRH

Anterior Pituitary:

­FSH  ­LH

Ovary responds

­follicle growth

Day 5

Ovary

 ­Estrogen

Day 6-14

Uterus:  generating new basal layer.

Ovary: Follicle is  continues to grow

­Estrogen & ­Inhibin

Anterior Pituitary responds by

¯FSH & LH release but

­synthesis & storage of FSH & LH

Day 14 (ovulation)

­High estrogen in the blood reach a critical level overriding any effect that inhibin has.

Anterior Pituitary Û FSH & Û LH (releasing the built up supply)

Ovary completes first meiotic division.

­LH level results in ovulation

Day 14 to Day 28

­LH  creates corpus luteum

Corpus luteum ­ estrogen ­progesterone

Uterus enters secretory phase

¯estrogen ¯progesterone negatively feedbacks  ¯LH & ¯FSH

¯LH causes ¯ corpus luteum & ¯ estrogen & ¯ progesterone &  endometrium sloughs off

¯estrogen takes the block off LH & FSH.

The cycle starts again.

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