This lesson will increase your knowledge of concepts covered

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This lesson will increase your knowledge of
concepts covered in the following TEKS for
biology
3.c Evaluate impact of research on scientific
thought, society, and the environment 3.e
Evaluate models according to their adequacy in
representing biological objects or events 3.f
Research and describe the history of biology and
contribution of scientists 10.a Interpret the
functions of systems in organisms 10.b Compare
the interrelationships of organ systems to each
other and to the body as a whole 11.a Identify
and describe the relationships between internal
feedback mechanisms in the maintenance of
homeostasis
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Previous Lesson Scientific Methodologies and
Publication
3
QUESTION Why is the U.S. government still
spending billions of dollars funding scientific
research?
Based on Nature, February 5, 2004.
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Advances in Biological Knowledge
Molecular Biology and Genetics
Immunology
Anatomy
Knowledge
The unknown Is still greater than the known
Ecology
Evolution
Today
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QUESTION If you had to design a study to
investigate the effects of a new drug on human
health, what type of design would you use?
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Two-group experimental design
Identity the variable which will test the
hypothesis
CONTROL GROUP
EXPERIMENTAL GROUP
The variable being tested
The variable being tested
is absent
is present
Record results
Record results
Compare and analyze the test results
Report on experimental design, test results, and
conclusions drawn from results
Based on Starr, C., Biology Concepts and
Applications, Brooks/Cole, Thomson Learning
7
QUESTION Why can nonscientists have
confidence in the information published in the
reputable popular press (Time Magazine, U.S. News
World Report, Newsweek)?
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Reputable Popular Press
Scientific Methodologies
World knowledge in scientific
journals Publication
Rejection Peer
review Submission of paper to scientific
journal
Observation Hypotheses Tests of
hypotheses Results
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Todays LessonMenopause and Hormone Replacement
Therapy
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Overview of Lesson

• Female reproductive system and menstrual cycle
• Menopause
• Hormone replacement therapy
• Womens Health Initiative

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Pathway of Egg if Unfertilized

• Follicle of ovary
• Oviduct
• Uterus
• Vagina

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Female System
Based onMader, S., Inquiry Into Life, Wm. C.
Brown Publishers
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Menstrual cycle the cyclic buildup and
breakdown of the endometrium as the uterus
prepares monthly for a blastocyst
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Hormones and Menstrual Cycle
Negative feedback
Negative feedback
Based on Mader, S., Inquiry Into Life,
McGraw-Hill
15
Negative Feedback Homeostasis
Overview
Negative feedback effects of estrogen and
progesterone are the prime homeostatic mechanisms
maintaining female sex characteristics at a
relatively constant level
Hypothalamus Pituitary Follicle Female
sexuality
Releasing hormone (GnRH)
LH FSH
Negative Feedback
Egg Development Estrogen Progesterone
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Hormonal Regulation of Ovarian and Uterine Cycles
Based on Mader, S., Inquiry, Wm. C. Brown
Publishers
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Ovulation
Based on Mader, S., Inquiry Into Life,
McGraw-Hill
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Hormones and Menstrual Cycle

• Pituitary produces FSH and LH
• FSH and LH cause follicle to develop and release
  egg
• Follicle produces estrogen and progesterone
• Estrogen and progesterone thicken endometrium to
  prepare for implantation of fertilized egg and
  suppress production of FSH and LH
• Egg not fertilized Egg fertilized

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If the Egg is Fertilized

• Fertilized egg implants in endometrium
• Embryo sends out hormonal message to the old
  follicle (corpus luteum) to let it know an embryo
  is present
• Old follicle continues to produce estrogen and
  progesterone to maintain endometrium

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Human Development
Based on Mader, S., Inquiry Into Life,
McGraw-Hill
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Family Planning Calendar
Based on Mader, S., Inquiry, Wm. C. Brown
Publishers
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If the Egg is Not Fertilized

• Unfertilized egg does not implant
• No hormonal message is sent to the old follicle
  and it stops production of estrogen and
  progesterone
• Without estrogen and progesterone, the
  endometrium breaks down and the menstrual flow
  occurs

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Hormonal Regulation of Ovarian and Uterine Cycles
Uterine Cycle
Based on Mader, S., Inquiry,Wm. C. Brown
Publishers
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Overview of Lesson

• Female reproductive system and menstrual cycle
• Menopause
• Hormone replacement therapy
• Womens Health Initiative

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Menopause

• In a womans 40s, estrogen production declines
• Symptoms of early menopause (perimenopause)
  appear and may last for 5 years
• Eventually estrogen production stops, menstrual
  cycle stops and woman enters menopause
• Average age to enter menopause is 51

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Symptoms of Early Menopause

• Hot flashes
• Dry skin
• Brittle hair
• Insomnia
• Vaginal dryness
• Mood swings

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Changing hormone levels with menopause
Based on Medical Essay Supplement to Mayo
Clinic Health Letter, October 1999
The uneven rising and falling of hormone levels
during perimenopause may be responsible for
menstrual irregularities and other problems
associated with menopause.
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Overview of Lesson

• Female reproductive system and menstrual cycle
• Menopause
• Hormone replacement therapy
• Womens Health Initiative

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Early History of HRT

• In early 1900s, scientists used extracts from pig
  ovaries to treat menopausal women
• By the early 1940s estrogen was being produced
  from pregnant mares urine (Premarin)
• By 1960s, the recommendation was that every
  women over 50 begin to using HRT

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Estrogen Only Therapy

• Beginning in 1960s, estrogen only was given to
  treat women with symptoms of menopause
• By 1970s, realized that estrogen only therapy
  increased rate to uterine cancer

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Todays Hormone Replacement Therapy

• Estrogen combined with progestin
• Lowers risk of uterine cancer

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Short-Term Benefits of HRT

• Cools hot flashes
• Combats insomnia
• Reduces vaginal dryness
• Levels mood swings

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Pre-2002 Hypothesized Long-Term Benefits of HRT

• Retards osteoporosis
• Reduces the risk of heart disease
• Neutralizes the risk of uterine cancer
• Reduces the risk of Alzheimers and colon cancer

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Osteoporosis a bone thinning disease that sets
the stage for serious fractures
Based on Newsweek Special Issue, Spring/Summer
1999
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MENOPAUSE AND BONE LOSS IN WOMEN
Based on A Harvard Woman Health Watch Special
Report 1996
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MENOPAUSE AND BONE LOSS IN WOMEN
Based on A Harvard Woman Health Watch Special
Report 1996
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THE HEART OF THE MATTERannual deaths per
100,000 U.S. women
Heart disease kills 6 times more women in their
post-menopausal years than does breast cancer
Based on Harvard Health Letter, October 1997
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Hypothesized Long-Term Risks of HRT

• Promotes the formation of gallstones and blood
  clots
• Increases the risk of breast cancer

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Spread of Breast Cancer
Based on Campbell et al.s Biology Concepts
Connections, Benjamin Cummings
Cancerous breast cells spread through the
lymphatic and circulatory systems to other areas
of the body.
Lymphatic and Circulatory Systems
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Overview of Lesson

• Female reproductive system and menstrual cycle
• Menopause
• Hormone replacement therapy
• Womens Health Initiative

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Before the Womens Health Initiative Study,
studies had shown a positive relationship
between taking HRT and lower heart disease (a
correlation). Why isnt this type of
correlative study used as proof that HRT reduces
heart disease?
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Women who took HRT may have more financial
resources, better health care and be more health
conscious than women that didnt use HRT.
Researchers could not tell whether hormones made
women healthy-or whether healthy women were more
likely to take hormones.
Correlation does not prove causation!
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Womens Health Initiative

• Study began in 1993 and was to last 15 years
• Involved 67,000 in three random clinical trials
  (Dietary Modification, Calcium/Vitamin D
  supplements, and HRT)
• HRT trial involved 16,000 women to assess the
  pros and cons of estrogen-progestin therapy (half
  received HRT and half received placebo)
• HRT trial was stopped in July 2002 when health
  risks were discovered
• Other two trials were continued

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Womens Health Initiative

• Women taking HRT
• increased risk of breast cancer, stroke, and
  heart disease
• decreased risk of hip fractures, colorectal
  cancer, and heart vessel disease (if taken early)
• Length of use may be a key factor

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But does HRT really result in significant health
risks?

• Viewed as percentages
• Heart attack rate was 29 higher in HRT group
• Stroke rate was 41 higher in HRT group
• Viewed as absolute numbers
• Instead of 30 heart attacks per 10,000 women, 37
  women would have heart attacks
• Instead of 21 strokes per 10,000 women, 29 women
  would have strokes
• Instead of 30 breast cancers per 10,000 women, 38
  women would have breast cancer

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Health Advisories

• Health advisories are made from a population
  perspective
• Individuals must decide how to respond to health
  advisories from a personal perspective

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A Boost for Hormone Therapy

• 2007 Update New Eng Journal Med
• Younger post-menopausal women 50-59 yrs of age
  post hysterectomy (took estrogen alone) showed up
  to 40 less calcium-based plaque in heart
  arteries than placebo group

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Next Lesson Prostate Cancer
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Lymphatic System
Based on Mader, S., Inquiry into Life, Wm. C.
Brown Publishers
50
Circulatory System
Back
Based on Mader, S., Inquiry Into Life,
McGraw-Hill