Lecture 8 Female Reproductive Physiology

Menstrual/Ovulatory Cycle

starts with the first day of the period and ends when the next period begins

oogenesis

the production, growth, and maturation of an egg; gametogenesis in the ovary

polar bodies

each of the small cells that bud off from an oocyte at the two meiotic divisions and do not develop into ova

• they die 

What is the average length of a menstrual cycle?

28 days

What are the two phases that the menstrual cycle are divided into?

follicular phase and luteal phase

follicular phase

• days 1-14

• release of LH (stimulates theca cells to make estrogen and progesterone)

• release of FSH (causes maturation of ovarian follicles)

Luteal Phase

• days 12-28

• high LH from ovulation stimulates empty follicle to turn into corpus luteum

Primodrial follicles

These structures are composed of the oogonia surrounded by a layer of flattened epithelial cells

primary follicles

Primary oocyte enlarges and is surrounded by the zona pellucide, granulosa cells, and the theca cells

zona pellucida

the thick transparent membrane surrounding a oocyte

granulosa cells

epithelial cells surrounding an oocyte in a follicle

theca cells

surround the granulosa cells and make hormones

secondary follicles

Distinguished by a larger oocyte and by follicular cells that have now multiplied and piled atop each to form layers

matrue/Graafian follicle

the secondary oocyte is pushed to one side of the follicle and a halo of granulosa cells forms around the oocyte

corona radiata

The halo of granulosa cells that surround the oocyte of a mature follicle

Theca cells respond to this hormone to turn cholesterol into a weak androgen (androstenedione)

LH

Granulosa cells respond to this hormone to convert the androstenedione into testosterone and then to estradiol

FSH

ovulation

the process of releasing a mature ovum into the fallopian tube each month

Ovulation is a positive feedback loop between these two hormones

LH and Estrogen

Basal Body Temperature

rises during ovulation in response to higher progesterone levels after ovulation

cervical mucus

the slimy secretion of mucous membranes located inside the cervix that increases in volume and elasticity right before ovulation

mittleschmirtz

“middle pain” with ovulation

The high estrogen and progesterone levels during the luteal phase exert negative feedback on these two structures

Hypothalamus and pituitary

Secretory phase

• High progesterone causes the endometrium to enter this phase

• when thickness increases, blood vessels increase, glands, fluids and nutrients increase 

• the endometrium is getting ready to receive the fertilized egg

What happens if the egg released at ovulation is not fertilized?

• the corpus luteum degenerates into corpus albicans

• progesterone levels fall

• the uterine lining degenerates and sheds

Premestrual symptoms

symptoms before day 1 of the cycle

what are premenstrual symptoms caused by

the high levels of progesterone during the luteal phase and/or the significant drop in progesterone that happens right before menstration

Menses

menstruation/period

Menarche

first menstrual period of a woman’s life

• av age is 13

Cycle day 1

the first day of menstrual bleeding is day 1

LMP

first day of last menstrual period

cycle length

time from start of one period to the start of the next

avg is 28 days but can vary from 21-45

flow

quantity/heaviness of bleeding

regular/irregular

if the cycle length is relatively constant, it's regular. If not, it's irregular

polymenorrhea

frequent cycles, occur more often than every 28 days

oligomenorrhea

infrequent cycles, occur less often than every 45 days, or fewer than 9 cycles per year

amenorrhea

absence of menses for 3 months or longer

the average amoutn of blood loss during a period

1-8 oz

Menorrhagia

heavy menstrual bleeding (more than 80ml)

dysmenorrhea

Dysmenorrhea

severely painful menstruation (debilitating)