Characteristics of human female ovulatory cycle:

1
Characteristics of human female ovulatory cycle

• 25-30 days in length
• includes menses
• ovulation occurs spontaneously
• cycles occur throughout the year
• no evidence of a period of estrus
• influenced by social factors (dormitory effect)
• one egg produced / month
• cycle length decreases with age

2
Phases of human ovarian cycle

• Menstrual phase (destructive phase)
• Follicular phase (estrogenic phase)
• Luteal phase (progestational)

3
Menstrual Phase

• Day 1 beginning of menses
• 4-5 days in length
• uterine lining degenerates
• follicle development continues

4
Follicular Phase

• Estrogen production gradually increases
• By day 13, 1 Graafian follicle present
• Remaining follicles become atretic by day 13
• Ovulation occurs on last day of follicular phase
  (day 14)
• Uterine events endometrium thickens blood
  supply increases

5
Ovulation

• E peak signals brain and pituitary that follicle
  is ready to ovulate
• GnRH release increases
• LH surge occurs (24-48 hrs later)
• LH surge initiates meiosis in oocyte
• ovulation occurs 9-12 hrs after LH surge peaks
• FSH surge also occurs (probably to recruit
  follicles for next cycles)

6
Luteal Phase

• last half of menstrual cycle
• follicle transformed to corpus luteum (CL)
• secretes progesterone (and estrogen)
• GnRH secretion inhibited
• no pregnancy gt CL degenerates (4 days prior to
  menstruation)
• uterine events
• thick and spongy
• glands secrete nutrients for possible embryo

7
Predicting ovulation

• calendar method
• ovulatory pain
• body temperature
• cervical mucus
• commercially available kits (urine LH
  measurements
• Laboratory methods (blood measurements of LH,
  progesterone)

8
Think, Pair, Share

• Yvonne wishes to become pregnant. She has a 32
  day cycle, and is interested in determining on
  which days of the cycle she is most likely to
  become pregnant. What is your advice?
• Sally does not wish to become pregnant, but also
  doesnt believe in the use of contraceptives. She
  is sexually active, and has a 29 day cycle. On
  what days of her cycle do you recommend she
  avoids having sex?

9
Dysmenorrhea

• menstrual cramps
• contraction of uterine smooth muscle
• likely caused by prostaglandins in menstrual
  fluid
• treatments antiprostaglandins
• Smokers are 2x more likely to experience negative
  effects of dysmenorrhea

10
Amenorrhea

• absence of menstruation
• primary amenorrhea
• menarche hasnt occurred by age 16
• associated with low amount of fat
• oligomenorrhea
• adult woman skips one or a few cycles
• common during periods of emotional distress or
  early stages of menopause
• secondary amenorrhea
• no menstruation for 6 months or more
• causes pregnancy, lactation, menopause, low body
  fat, intense exercise, tumors

11
Luteal Phase Defect

• Shortened luteal phase
• Due to
• Inability to produce enough prog or
• Inability of endometrium to respond to prog
• Result endometrium unprepared for implantation
• Assoc. with light periods
• Detected by uterine biopsy
• Rx progesterone supplementation

12
Menopause

• average age of menopause in U.S. 52 years
• causes
• GnRH release changes
• ovaries dont respond to LH, FSH
• depletion of germ cell stock
• estrogen falls
• symptoms hot flashes, psychological and
  emotional changes (?)
• treatment hormone replacement therapy