Psychology 2075 Lecture Notes - Luteal Phase, Sex Steroid, Corpus Luteum

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Published on 12 Apr 2013
School
Western University
Department
Psychology
Course
Psychology 2075
Professor
Chapter 5: Sex Hormones, Sexual Differentiation, and Menstruation
o Prenatal Period= where structural differences between male and females arise process
called Prenatal Sexual Differentiation
Sex Hormones
o Hormones= chemical substances secreted by the endocrine glands into the
bloodstream
o Fx felt rapidly and spread all over the body
o Androgens= group of male sex hormones (Testosterone)
o Testosterone: hormones released by testes in the male (lower levels in
females)
o Estrogen= group of female sex hormones
o Progesterone= female sex hormone released by ovaries
o Endocrine sex glandsTestes (male), Ovaries (female)
o Hypothalamus regulates the pituitary glands (regulates levels of sex hormones)
o Hypothalamus= regulates vital functions like eating,drinking and sexual
behaviour
o Master Gland= pituitary 3 lobes: anterior, intermediary and posterior
Anterior: interacts with gonads
Sex Hormone Systems in Males
o HPG Axis= hypothalamus-pituitary-gonad axis negative feedback loop that
controls production of sex hormones
o Hypothalamus= Gonadotropin-releasing Hormone (GnRH) which controls levels of..
o Pituitary= Follicle-stiumlating Hormone (FSH) + Luteinizing hormone (LH)
o FSH sperm production
o LH control testosterone production
o Testes= Testosterone male hormone, stimulates secondary sex characteristics,
maintaing genitals and sperm producing abilities, growth of muscle/bone
o Negative feedback loop: LH tells Testes to make testosterone but when those levels
get high the hypothalamus reduces its production of GnRH (LH levels
reduce/Testosterone levels reduce)
o One study showed that men’s testosterone levels displayd weekly fluctuations and
that cycles might synchronize with partners
o Inhibin= hormone made by testes (sertoli cells) regulates FSH levels in negative
feedback loop just as testosterone does with LH
o Contraceptive because suppresses FSH therefore sperm production
Sex Hormone System in Females
o HPG axis= similar to males but in ovaries
o Hypothalamus GnRH
o Pituitary FSH + LH : regulate estrogen and progesterone
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o Prolactin: makes milk, stimulates mammary glands
o Oxytocin: ejection of milk, stimulates contractions during labor, snuggling
hormone
o Ovaries Estrogen + Progesterone
o Estrogen: changes of puberty (secondary sex characteristics), maintains
mucous membranes of vagina, stops growth of bone/muscle
o Makes Inhibin controls FSH production in negative feedback loop of
menstrual cycle
The Menstrual Cycle
o Unique to humans, apes, monkeys
o Dogs/horses have estrous cycles
o No bleeding only some spotting
o Ovulation occurs when in ―heat‖/estrus slight spotting
o Female animals only engage in sexual activity when in heat
o Menstrual ovulation occurs midway between the periods of menstruation
The Phases of Menstrual Cycle
o 4 phases: each have hormonal, ovarian and uterine changes
1) Follicular Phase (Proliferative) FSH high levels stimulate follicles in ovaries
to mature egg and releases estrogen
2) Ovulation Phase release of mature egg, stimulated by LH surge due to high
levels of estrogen stimulating GnRH/inhibits FSH
3) Luteal Phase (Secretory) LH turns follicle in to Corpus Luteum (makes
progesterone)
High levels of progesterone inhibit LH, corpus luteum degenerates
(sharp decline in estrogen/progesterone at end of phase)
Falling levels of estrogen stimulate FSH and starts again
4) Menstruation shedding of the uterine lining (endometrium)
Triggered by: Estrogen/progesterone are low/FSH on the rise
o Follicular Phase= high levels of estrogen growin the endometrium/thicken
(proliferates)
o Luteal Phase= progesterone released stimulates endometrium to release nourishing
substances
o Corpus Luteum makes estrogen/progesterone for 10-12 days and if not
pregnant sharp decrease in these hormones at end of period (uterine lining
shed)
o Menstraul Fluid= Blood from endometrium + degenerated cells/mucus from
vagina/cervix (2 ounces/4 tablespoons)
o Menstrual Cup= reusable, enviro-friendly
Length and Timing of Cycle
o Average= 28 days but varies
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o Studies say women with higher variability in cycle have higher levels of androgens
o Day 1-4/5= Menstruation
o Day 5-13= Follicular Phase
o Day 14= Ovulation
o Day 15-28= Luteal Phase
o In women with variation Luteal Phase stays constant (14 day range till mentruation)
o Ex: 44 day cycle= ovulation on day 30
o Mittelschmerz (middle pain)= some woman say can feel abdominal pain on ovulation
day
o Ovulation does not always occur even if menstruation does= Anovulatory Cycle
o Once/twice a year women in their 20s/30s
o Common in puberty and menopause
Other Cyclic Changes
o 2 other processes: Cervical Mucus Cycle + Basal Body Temperature Cycle
o Cervical Mucus Cycle glands in cervix that release mucus in menstrual cycle
o Protects entrance of cervix: keeping bacteria out
o Responds to changes in estrogen= increase in estrogen, mucus alkaline, thick
o LH begins before ovulation= mucus becomes thin and watery make sperm
passage easier
Dried it looks like fern-shaped pattern, detects for ovulation = Fern
test
o Basal Body Temperature low in follicular phase, dip during ovulation, rises after
by .03 degrees, higher for rest of cycle
o Progesterone= raises body temperature during Luteal phase (important for
couples using fertility awareness method of birth control)
Menstrual Problems
o Dysmenorrhea painful/heavy menstruation, headaches, nausea, pressure and
bloating of pelvis
o Cause by high levels of Prostaglandins chemicals released by uterus causes
muscles to contract
o Uterine Contractions + lack of oxygen blood + heightened nerve sensitivity=
menstrual cramps
o Treatment NSAIDS= Ibruprofen (Advil), Naproxen (Aleve)
They are anti-prostaglandins
Orgasm helps relieve pelvic edema that causes discomfort
o Endometriosis endometrial tissue grows outside of uterus (ovaries/fallopian
tubes/vagina/rectum
o Symptoms vary on location of growth: very painful periods, pain during
sexual activity, infertility
o Very serious could lead to sterility
o Treatment Hormones or if very severe laser surgery
o Amenorrhea absence of menstruation
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Document Summary

Chapter 5: sex hormones, sexual differentiation, and menstruation: prenatal period= where structural differences between male and females arise process called prenatal sexual differentiation. High levels of progesterone inhibit lh, corpus luteum degenerates (sharp decline in estrogen/progesterone at end of phase) Falling levels of estrogen stimulate fsh and starts again: menstruation shedding of the uterine lining (endometrium) Gonads: gonads become testis at 7 weeks, y chromosome= sex determining region (sry, if tdf (testis-determining factor) is present= male if not female, x chromosome= genes that control ovaries and testes (sperm making) Must be corrected by surgery or hormonal therapy. Optimal before age 5 otherwise man will be sterile (high temp of testes inside body stop sperm making: inguinal hernia may reopen later in life, passageway through intestine and enter scrotum. Homologous organs: homologous=developed from same embryonic tissue, analogous= similar function (see table 5. 1 page 111, ex: ovaries and testes homologous= develop from undifferentiated gonad.

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