Ovaries

Ovaries

produce gametes

• estrogen and progesterone

• Germinal epithelium: a layer of simple cuboidal epithelium that covers the ovary is actually the ovary’s visceral peritoneum

• tunica albuginea: the dense connective tissue layer just under the germinal epithelium

Cortex

the outer layer where the product and maturation of gametes occur

Medulla

the inner layer that carries the blood vessels

• blood supply is through the various ovarian ligaments

Oogenesis begins in…

utero

• before birth, females have made all the oocytes they will ever make; mitosis of oogonia (female stem cells) cease

Millions of primordial follicles

• Females stuck in Prophase I = primary oocytes

• in utero = 7 million primary oocytes

• at birth = 2 million primary oocytes

• at onset of puberty = 300,000 - 400,000 primary oocytes

• in a typical women’s entire reproductive life, only 400-500 gametes will finish meiosis I to become secondary oocytes arrested in metaphase II

Oogenesis

• the primary oocyte remain stuck in prophase I until the onset of puberty

• The hormones of puberty stimulate one (sometimes 2) 1 primary oocyte per month to complete meiosis I

• This results in a secondary oocyte and a polar body (with most cytoplasm in the oocyte)

• it is NOT an ovum, but a secondary oocyte that is ovulated! in other words, meiosis II has not yet been completed (stuck in metaphase II)

• fusion of the sperm with the secondary oocyte stimulates the completion of meiosis II (a second polar body then results)

• ovum exits for a very short time before it becomes a zygote

Fallopian tubes

also called oviduct or uterine tube; hollow muscular tubes ~5 in long

Infundibulum

an expanded funnel contains many finger like projections called fimbriae lined with cilia

Ampulla

most of the middle portion of the tube; the site of fertilization

Isthmus

short segment adjacent to the uterine wall

The fallopian tube enters…

the uterine wall at the uterine ostium

• weak peristalsis occurs in smooth muscle in the days around ovulation; oocyte takes 3-4 days to make the trip

Ectopic pregnancy

• development outside of the uterus

Tubal ligation

is a surgical hospital procedure (requiring anesthesia) whereby the uterine tubes are cut, and the ends are tied off or cauterized shut to prevent both sperm from reaching the oocyte and the oocyte from reaching the uterus

Vagina

• for sexual intercourse as well as birth canal

• nonkeratinized stratified squamous and rugae

Ovarian cycle

million’s of primordial follicles are present at birth

• contain primary oocyte

Primordial follicles

• primary oocyte

• millions before birth

• contains primary oocyte; stopped in prophase I

Primary follicle

• primary oocyte covered by stratified cuboidal epithelium

• about 20/month

Secondary follicle

• has antrum (a few develop)

• still primary oocyte

Vesicular follicle

• mature (one develops)

• secondary oocyte continues to metaphase II

ovulation

• secondary oocyte

• fertilization (finishes meiosis)

• egg/zygote

Ovulation…

results from a surge of LH from the anterior pituitary gland

What happens to the secondary oocyte?

• fertilized and becomes egg/zygote OR not fertilized and exits body at menstruation

What happens to the vesicular follicle following implantation of blastocyst

• becomes corpus luteum

• produces Progesterone and Estrogen to maintain endometrium

• Continues to produce Progesterone under influence of HCG (human chorionic gonadotropin)

• Placenta eventually produces Progesterone and Estrogen through birth

What layers thickens and thins during Uterine cycle?

Endometrium

• What actually grows to increase thickness? → uterine glands and blood vessels

Development in the…

morula