What Happened to 28 Days?
A Clicker Case About the Human Menstrual Cycle
by
Tamar L. Goulet
Department of Biology
University of Mississippi
1
CQ#1: My knowledge of the menstrual
cycle is:
A.
B.
C.
D.
E.
Nonexistent
Fair
Good
Very good
Excellent
Opinion
2
CQ#2: The length of a human menstrual
cycle is __ days:
A.
B.
C.
D.
E.
20
24
28
32
Any of the above
3
CQ#3: A woman has a 24-day cycle. She
will ovulate on day__
A.
B.
C.
D.
E.
6
10
12
14
18
4
CQ#4: The case is about Ann, who is:
A.
B.
C.
D.
E.
A single mother of three
A high school senior
A married college student
A faculty member in the Biology Department
A waitress
5
If you were Karen, what questions
would you ask?
6
Ann & Karen’s Conversation
“So, when was the 1st day of your last period?”
asked Karen.
“February 1st,” replied Ann.
“How long is your menstrual cycle?” asked Karen,
her pen poised in the air.
“28 days,” Ann replied quickly.
“Is it always 28 days?” asked Karen.
“Isn’t every woman’s menstrual cycle 28 days?”
asked Ann.
7
CQ#5: You asked a friend about her menstrual
cycle. The length of your friend’s menstrual cycle
falls between ___ days.
A.
B.
C.
D.
E.
20-23
24-27
28-31
32 and above
Other
8
Ann & Karen’s Conversation
“Ok, let’s step back a bit. Which organs are directly
involved in the menstrual cycle?” asked Karen.
List the organs that are involved.
9
Female Reproductive Anatomy
(oviducts)
10
Ann & Karen’s Conversation
“Are these organs physically connected?” asked Karen.
“Well, no” answered Ann incredulously. “After all, my
hypothalamus is up here,” said Ann, pointing to her
head, “and my ovaries are down there,” she continued
as she pointed to her jeans, and then looked around
self-consciously to see if she had been overheard.
11
Ann & Karen’s Conversation
“Good, good,” nodded Karen. “So, how does the
hypothalamus communicate with the ovaries?”
12
Hormones
• List all the hormones that are involved
with the menstrual cycle.
• Specify where they are produced.
13
Menstrual Cycle Hormones
1.
2.
3.
4.
5.
GnRH - Gonadtropin-releasing hormone.
LH - Luteinizing hormone.
FSH - Follicle stimulating hormone.
Estrogen.
Progesterone.
1 – hypothalamus.
2 & 3 - anterior pituitary.
4 & 5 - within ovary.
14
CQ#6: How do hormones get from the
anterior pituitary to the ovaries?
A.
B.
C.
D.
E.
Gravity
Osmosis
In the blood stream
In the interstitial fluid
Through nerve impulses
15
Ann & Karen’s Conversation
“Ann,” Karen asked gingerly. “Do you know what
happens during a menstrual cycle?”
“Of course!” replied Ann adamantly.
Can you explain what happens?
16
Hypothalamus
Anterior Pituitary
Uterus
Ovary
17
Hypothalamus
Anterior Pituitary
1. FSH
Uterus
Thickening of lining
2. LH
Ovary
Estrogen
a) Follicle growth
a) Egg release (=ovulation) +
b) Scar tissue (=corpus luteum)
Progesterone
18
CQ#7: Unless a pregnancy occurs, the
corpus luteum will degenerate after ____
days.
A.
B.
C.
D.
E.
6
10
12
14
18
19
20
CQ#8: Without the corpus luteum and
progesterone, the uterine lining will:
A.
B.
C.
D.
Remain the same thickness
Increase in thickness
Decrease slightly in thickness
Shed, i.e., menstrual flow
21
Ann & Karen’s Conversation
“Ok, what was the first day of your last menstrual
cycle?” asked Karen.
“February 2nd,” repeated Ann.
“And what was the first day of the cycle before that?”
asked Karen.
“Umm, January 1st,” said Ann.
“So, how long is your personal menstrual cycle?”
prodded Karen.
Ann paused to think. What was it…?
22
Ann & Karen’s Conversation
“So your cycle is 32 days long,” stated Karen. “Can you
figure out when you ovulate?” she asked.
“I don’t feel when I ovulate,” said Ann.
“Most women do not,” stated Karen. “But, there are
signs.”
23
Basal body temperature changes during cycle
(c) BabyCenter LLC
24
CQ#9: After ovulation, for the remainder
of the cycle, a woman’s basal body
temperature:
A.
B.
C.
D.
Does not change
Oscillates, generating hot flashes
Goes up slightly and stays up
Goes down slightly and stays down
25
Cycle Day
Day of week
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
Date
Time
99.1
99.0
98.9
98.8
98.7
98.6
98.5
98.4
98.3
98.2
98.1
98.0
97.9
97.8
97.7
97.6
97.5
97.4
97.3
97.2
97.1
97.0
96.9
CM *
Intercourse
Cervical
Mucus
textures
* CM = cerv ical mucus: P=period, D=dry, M=mucus, E=eggwhite
Notes: (List any changes to your routine)
26
Cycle Day
Day of week
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
Date
Time
99.1
99.0
98.9
98.8
98.7
98.6
98.5
98.4
98.3
98.2
98.1
98.0
97.9
97.8
97.7
97.6
97.5
97.4
97.3
97.2
97.1
97.0
96.9
CM *
Intercourse
Cervical
Mucus
textures
* CM = cerv ical mucus: P=period, D=dry, M=mucus, E=eggwhite
Notes: (List any changes to your routine)
cervical secretions change throughout the cycle
27
Ann & Karen’s Conversation
“I didn’t watch out for those signs!” wailed Ann.
“Even if you did not, we can still calculate when you
ovulated,” said Karen.
28
CQ#10: Ann has a 32-day cycle. She will
ovulate on day ___.
A.
B.
C.
D.
E.
6
10
12
14
18
29
Menstrual
5 days
phase
Menstrual
10 days
28 – day cycle
phase
Menstrual
13 days
32 – day cycle phase
24 – day cycle
Day 10
Day 14
Day 18
Follicular phase
Menstrual
phase
Menstrual
14 days
phase
Menstrual
14 days
phase
14 days
Luteal phase
Ovulation
30
CQ#11: Within the female human
body, sperm can survive up to:
A.
B.
C.
D.
E.
1 day
2 days
3 days
4 days
5 days
31
Ann & Karen’s Conversation
“So, I ovulated on day 18?” asked Ann.
“Yes you did,” confirmed Karen.
“Since we had sex on day 16, I have nothing to worry about,”
said Ann with a sigh.
“Not necessarily,” said Karen. “A male’s sperm can stay alive in
a female body for up to 5 days.”
“You have got to be kidding,” whispered Ann in an appalled
voice.
“But,” Karen pointed out, “you assumed you had a 28 day
cycle when in fact yours is 32. So guess what? You’re not
late,” stated Karen.
32
Ann & Karen - Follow Up
A week later, Ann & Karen met for coffee again.
“I did not hear from you, so I assumed… Well…?” asked Karen
picking up their conversation from the previous week.
“I got my period,” said Ann. “I never counted how many days
were between my periods,” she admitted sheepishly. John &
I are checking our options for family planning. I’m not ready
yet to be a mom.”
“At least you know your own body better now,” concluded
Karen. “What kind of coffee do you want today? My treat.”
33
CQ#12: The length of a human menstrual
cycle is __ days:
A.
B.
C.
D.
E.
20
24
28
32
Any of the above
34
CQ#13: A woman has a 20-day cycle. She
will ovulate on day__
A.
B.
C.
D.
E.
6
10
12
14
18
35
Slide Credits
Slide 10
Description: Schematic drawing of female reproductive organs, frontal view.
Source: Composite image derived from http://commons.wikimedia.org/wiki/File:Scheme_female_reproductive_system-en.svg and
http://en.wikipedia.org/wiki/File:Order_of_changes_in_ovary.svg
Author: Female anatomy drawing courtesy of Centers for Disease Control and Prevention; inset of ovary by Wikimedia contributor Shazz
Clearance: Female anatomy drawing is public domain; ovary inset is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
Slides 17 and 18
Description: Schematic of menstrual cycle events.
Source: Case author
Author: Tamar L. Goulet
Clearance: Used with permission.
Slide 20
Description: Diagram of the menstrual cycle.
Source: Wikimedia Commons, http://commons.wikimedia.org/wiki/File:MenstrualCycle2_en.svg
Author: Wikimedia contributor Isometrik
Clearance: This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
Slide 24
Description: Basal body temperature and cervical mucus chart--sample.
Source: ©BabyCenter LLC
Link: http://assets.babycenter.com/ims/Content/bbt_sample_chart.pdf
Clearance: Used with permission.
Slide 27
Description: Three line drawings of hands showing cervical secretions.
Source: Fertility UK (http://www.fetilityuk.org), “Recognising the Changes in Cervical Secretions” (http://fertilityuk.org/nfps401.html)
Clearance: Used with permission of Jane Knight, Fertility Nurse Specialist, Fertility UK
Slide 30
Description: Schematic showing multiple cycles involved in the menstrual cycle.
Source: Case author
Author: Tamar L. Goulet
Clearance: Used with permission.
36