Chapter 3 Hormones and Sexuality

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Chapter 3Hormones and Sexuality

• For use with text,
• Human Sexuality Today,
• 5th edition.
• Bruce M. King
• Slides by Callista Lee

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What are hormones?

• Hormones are chemical substances secreted by the
  ductless glands of the Endocrine System directly
  into the bloodstream which carries them to other
  parts of the body where they exert their
  influence on other glands or target organs.
• The pituitary gland, located just beneath the
  brains hypothalamus is part of the Endocrine
  System.

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Brain Pituitary Gonad feedback loop in women

• Hormones produced by the gonads (the ovaries in
  women) are released into the bloodstream and are
  read by the pituitary gland which will alter
  its output of FSH and LH in response.

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Reproductive hormones

• Follicle-stimulating hormone (FSH) governs the
  production of ova in women and sperm in men. FSH
  is produced by the pituitary gland.
• Luteinizing hormone (LH) triggers ovulation in
  women and the production of androgens (male
  hormones) in men. LH is also produced by the
  pituitary gland.
• Both FSH and LH are under the control of
  gonadotropin-releasing hormone (GnRH) which is
  produced in the brains hypothalamus.

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The menstrual cycle its all about eggs

• Each ovum (egg) is surrounded by cells which form
  a protective follicle.
• At birth, each ovary has about 300,000 to 400,000
  primordial (immature) follicles.
• Each month about 1000 follicles begin but never
  complete the maturation process.
• At puberty only about 200,000 follicles/ova
  remain and some will now complete the maturation
  process each menstrual cycle.

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Changes within the ovaries
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Menstruation

• Menstruation actually takes place at the end of
  the menstrual cycle, after a mature ovum has been
  released (ovulation) but has failed to become
  fertilized by sperm.
• The blood-rich endometrial lining of the uterus
  that had thickened in anticipation of a pregnancy
  sloughs off (menstruation) while other follicles
  in the ovaries begin the maturation process for
  the next cycle.

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Myth of the 28-day cycle

• 28 days is only the statistically average length
  of an adult human womans menstrual cycle.
• Consistent 28-day cycles are not very common.
  Variance between and within individuals is to be
  expected.
• What we refer to as Day 1 of the cycle is
  actually the first day of menstrual bleeding
  (menstruation) at the end of the process.

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Hormonal, ovarian and uterine changes during a
28-day cycle

• Since your face is not on the cover of this
  textbook, dont expect your cycle to look exactly
  like this one each month.
• Allow for differences from month to month and
  between individuals.

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Menstrual Cycle Days 5 - 13Preovulatory Phase

• In this follicular or proliferative phase the
  pituitary secretes relatively high levels of FSH.
  
• The growing follicle becomes a temporary
  endocrine gland, secreting increasing amounts of
  estrogen which inhibits FSH production in the
  pituitary.
• When estrogen levels reach their peak, the
  pituitary releases a surge of LH.

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Menstrual Cycle Day 14Ovulation

• Again, day 14 is only an average ovulation
  occurs anywhere from 12 16 days before the next
  menstrual flow.
• The LH surge signals the onset of ovulation
  within 12 to 24 hours.
• The Graafian (mature) follicle has moved to the
  surface of the ovary where the follicle will
  rupture, expelling the ripe ovum into the
  abdominal cavity.

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Menstrual Cycle Days 15 - 28 Postovulatory Phase

• This phase is also called the luteal or secretory
  phase because the cells of the follicle remain in
  the ovary, renamed the corpus luteum, where
  they will produce large amounts of progesterone.
• Progesterone inhibits release of LH from the
  pituitary gland and further prepares the
  endometrial lining of the uterus to receive a
  fertilized egg.

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Menstrual Cycle Days 1 to 4 Menstruation

• In most cycles fertilization and implantation do
  not occur. The corpus luteum deteriorates and
  both progesterone and estrogen levels decline.
• This decline in the hormones needed to maintain
  the endometrium leads to the degeneration of the
  endometrial lining which is sloughed off and shed
  over a 3 to 6 day period along with blood and
  cervical mucus.

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Pheromones

• Pheromones are chemical substances secreted
  externally by animals that convey information to
  and produce specific responses in members of the
  same species.
• For example, when a female cat goes into heat
  male cats will pick up her scent and become
  sexually aroused.

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Menstrual Synchrony

• Women who live together and are regularly exposed
  to the pheromones (detected non-consciously) in
  each others sweat often experience changes in
  the length of their individual menstrual cycles
  so that they become synchronized.
• Women with abnormal cycles tend to develop more
  normal cycles when exposed to male sweat.

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Aphrodisiac Colognes?

• Although perfume makers have long been hopeful to
  develop an aphrodisiac based on human
  pheromones, there is not yet any evidence to
  suggest that human sexual desire and behavior is
  affected by natural body odors.
• Even menstrual synchrony may be due to factors
  much more complex than simple exposure to the
  natural odors of others.

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Menstrual versus Estrous Cycle

• The monthly menstrual cycle allows humans many
  opportunities for procreation throughout the
  year.
• Regular menstruation may also allow the body to
  rid itself of potentially harmful bacteria in the
  uterus on a regular basis.
• Most animals experience an estrous discharge and
  sexual/reproductive receptivity just once or
  twice a year.

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Historical Hebrew and Modern Jewish Attitudes

• Biblical-age Hebrews regarded menstruating women
  as impure and forbid all contact with men for 7
  days.
• A ritual bath, the Niddah, was required before
  she could again leave her home and have any
  contact with men.
• Orthodox Jews still adhere to these practices to
  a lesser degree.

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Menstrual Taboos and Celebrations

• In many cultures menstrual taboos emphasize the
  low status and inferiority of women (e.g.,
  Hunter-gatherer societies such as the Havik
  Brahmins, Lele, Kolish peoples).
• However, Japanese and many Native American
  peoples celebrate a girls first menstruation as
  a positive experience and entry into womanhood.

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Current American Attitudes

• Most Americans view menstruating women as less
  likeable, less agreeable, less clean and more
  irritable.
• The large majority of Americans seldom initiate
  sex during menstruation.
• Actually, there is nothing dirty or nasty about
  menstruation as it is a normal, healthy event.

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Menstrual Problems Amenorrhea

• Amenorrhea is the absence of menstruation for 6
  months or longer
• Ogliomenorrhea is the absence of periods for
  shorter intervals and is common in the first few
  years following menarche (first menses)
• Pituitary and ovarian problems
• Low levels of body fat, especially among athletes
  or anorexics.

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Menstrual Problems Premenstrual Syndrome (PMS)

• 3 to 14 days prior to the menstrual period,
  during the postovulatory/luteal phase
• Bloating, breast tenderness, abdominal swelling,
  swollen hands and feet, weight gain,
  constipation, and headaches
• Depression, anxiety, tension, irritability and
  inability to concentrate
• 75 of women experience some symptoms

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Menstrual Problems PMS vs. PMDD

• Most women who perceive themselves as having PMS
  are actually misattributing symptoms of stress,
  poor health and work problems.
• Premenstrual Dysphoric Disorder (PMDD) occurs in
  3 8 of women and includes much more severe
  symptoms which markedly interfere with their
  lives.

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Causes and Treatments of PMS and PMDD

• Normal levels of estrogen and progesterone may
  interact with brain chemicals such as serotonin
  to produce symptoms.
• Antidepressant medications often reduce tension
  and irritability.
• Physical symptoms are often relieved by combating
  water retention and improving diet and exercise.

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Menstrual Problems Dysmenorrhea

• Painful abdominal cramping, backaches, headaches,
  feeling bloated and nausea
• In 7 to 15 of women symptoms are severe, most
  commonly in women under age 25.
• Causes include pelvic abnormalities,
  endometriosis and over production of
  prostaglandins.

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Menstrual Problems Endometriosis

• Endometrial tissue also grows outside the uterus,
  often involving the Fallopian tubes, ovaries,
  external surface of the uterus, vagina and pelvic
  cavity.
• At menstruation this abnormal tissue will slough
  off but the blood cannot drain normally, causing
  inflammation and scar tissue to form.
• It is found in 25 to 40 of women examined for
  infertility.

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More on Menstrual Problems

• Endometriosis is treated with hormone therapy,
  including birth control pills, and/or surgery.
• Toxic Shock Syndrome (TSS) is caused by bacteria
  that cause flu-like symptoms.
• 85 of TSS cases are related to menstruation and
  many are linked to use of super-absorbent
  tampons.
• TSS can lead to death if not treated properly.

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Regulation of Male Hormones

• The hypothalamus, pituitary gland and testicles
  operate in a feedback loop.
• GnRH causes release of FSH which causes sperm
  production. FSH production is kept in check by
  hormones from the testicles.
• GnRH also causes release of LH which increases
  testosterone production. High levels of
  testosterone decreases GnRH production.

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Brain Pituitary Gonad feedback loop in men

• Hormones produced by the gonads (the testes in
  men) are released into the bloodstream and are
  read by the pituitary gland which will alter
  its output of FSH and LH in response.

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Hormones and Sexual Desire

• Testosterone plays a role in both male and female
  levels of sexual desire.
• Testosterone levels are linked not only
  biological factors but also to levels of sexual
  activity as well as exposure to non-sexual
  psychological arousal.
• Severely low levels of testosterone are clearly
  linked to low levels of sexual desire.

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Anabolic Steroids

• Derivatives of testosterone, these synthetic
  drugs promote muscle growth by enhancing protein
  uptake in muscle cells. Both muscle mass and
  strength are enhanced.
• Administered in proper dosages. anabolic steroids
  have therapeutic value for people recovering from
  certain illnesses.

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Misuse of Anabolic Steroids

• Athletes tend to take dosages 100 times the
  therapeutic dose.
• Physical harm includes high blood pressure,
  serious cardiovascular disease, liver and
  prostate tumors, decrease in testicular size,
  breast lumps and impaired reproduction.
• Psychiatric harm includes anxiety, irritability,
  depression, impaired judgment and paranoia.