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6.6.2: Outline the role of hormones in the menstrual cycle, including FSH (follicle stimulating hormone), LH
(leutenizing hormone), estrogen and progesterone
FSH + LH: increase production/secretion of estrogen by the follicle cells of the ovary
Estrogen: enters bloodstream + targets endometrium tissue of the uterus, resulting in increased blood vessels in the
endometrium
Progesterone: maintains thickened, highly vascular endometrium
6.6.3: Annotate a graph showing hormone levels in the menstrual cycle, illustrating the
relationship between changes in hormone levels and ovulation, menstruation and the thickening
of the endometrium http://bcs.whfreeman.com/thelifewire8e/default.asp
6.6.4: List 3 roles of testosterone in males
1. Determines development of male genitalia during embryonic development
2. Ensures development of secondary sex characteristics during puberty
3. Maintains the sex drive of males throughout their lifetime
6.6.5: Outline the process of in vitro fertilization
Woman receives FSH injections for ~10 days to ensure large number of Graafian follicles
Sperm cells from male collected into container Several eggs harvested surgically Harvested eggs mixed with sperm cells in
separate culture dishes Microscopes used to reveal which ova are
fertilized and whether early development appears normal
2 or 3 healthy embryos are introduced do decrease risk of failure
Unused embryos can be frozen and used later
6.6.6: Discuss the ethical issues associated with IVF
For IVFEnables couples otherwise unable
to have a familyGenetic screening on embryos
possible to eliminate the chance of passing on genetic diseases
Will lead to further benefits in reproductive biology
6.6.6: Discuss the ethical issues associated with IVF
Against IVFEmbryos that are cultured but not
implanted are frozen/destroyedComplex legal issues over frozen
embryos when couples split upGenetic screening could allow society to
customize childrenMultiple births + problems w/ multiple
births more likely with IVF
Pituitary Gland!
Produces FSH + LHStimulated by gonadotrophin from
the hypothalamus (part of the female’s brainstem)
In which of the following structures does meiosis take
place?EpididymisProstate glandTestisSeminal Vesicle
How does fertilization differ from copulation?
Fertilization always produces a zygote
Only fertilization involves gametesFertilization is a conscious eventFertilization can spread HIV
Do the levels of progesterone and FSH increase or remain low during the first few days of the
menstrual cycle?
Progesterone and FSH both remain lowProgesterone remains low but FSH
increasesProgesterone increases but FSH remains
lowProgesterone and FSH both increase
What are the levels of the hormones estrogen, progesterone, LH and FSH during the menstrual
cycle at the time of ovulation?
Estrogen Progesterone LH FSH
A High Low High High
B High High Low High
C Low High High Low
D Low Low Low Low
How is in vitro fertilization different from natural fertilization in humans?
In vitro fertilization involves artificial injection of sperm into the uterus
In vitro fertilization only involves one parent
In vitro fertilization happens outside the body
In vitro fertilization uses stem cells instead of eggs
In vitro fertilization happens outside the body!Sperm is not injected, only mixed
with egg in culture dishInvolves sperm provided by male
and eggs surgically removed from female (two parents)
During fertilization in humans, where do the acrosome and the cortical reactions
occur most often?
Acrosome reaction
Cortical reaction
A Vagina Uterus
B Uterus Oviduct
C Oviduct Uterus
D Oviduct Oviduct
Acrosome reaction
Cortical reaction
D Oviduct Oviduct
• Both are reactions that occur between the sperm and the egg leading up to fertilization
• Sperm move to the Oviducts (fallopian tubes)
What is the location and function of Sertoli cells?
Location Function
A Seminiferous tubule
Feeding developing sperm
B Seminiferous tubule
Feeding interstitial cells
C Epididymis Feeding developing sperm
D Epididymis Feeding interstitial cels
In the menstrual cycle in humans, which hormone causes the wall of the follicle to
develop after ovulation and to secrete more progesterone?
EstrogenFSHLHOxytocin
Which of the following are functions of the placenta?
1. Gas exchange2. Stimulation of uterine contractions3. Secretion of progesterone4. Secretion of estrogens
A) 1 only B) 3 + 4 onlyC) 1,3+4 only D) 1,2,3 + 4
C) 1, 3, and 4
Gas exchange, secretion of progesterone/estrogen
High level of progesterone + estrogen are needed throughout pregnancy
The placenta and capillaries of the mother exchange materials such as nutrients, water and gas
What happens to the zygote immediately after fertilization?
It remains in the uterus until placenta develops
It implants in the wall of the uterusIt divides by meiosis to form an embryoIt divides by mitosis to form a blastocyst
It divides by meiosis to form a blastocyst
About 100 cells largeSurrounding cell layer called the
trophoblast - helps form the fetal portion of the placenta
Interior cells are the inner cell mass- will become embryo body
Fluid-filled cavity
Why is human chorionic gonadotrophin (HCG)
important in early pregnancy?
It is required for equal cell divisions in the growing embryo
It stimulates the ovary to continue production of estrogen and progesterone
It increases the rate of cell division in the embryo
It promotes growth of the inner cell mass within the embryo
Why is human chorionic gonadotrophin (HCG)
important in early pregnancy?It stimulates the ovary to continue
production of estrogen and progesteroneThese two hormones are needed at high
levels throughout pregnancyHCG maintains the corpus luteum in the
ovary of the woman after fertilizationCorpus luteum secretes estrogen and
progesterone longer than it would normallyLater in pregnancy, Placenta takes over
What does oxytocin control?
Brain development of the fetusOnset of ovulationStimulation of uterine contractionsImplantation of the blastocyst
What does oxytocin control?
Stimulation of uterine contractions
Oxytocin is a peptide hormone that causes uterine contraction
Low levels of oxytocin early on (no need to have contractions due to lack of development)
Works in a POSITIVE FEEDBACK mechanism Each contraction results in uterine mechanoreceptors
sending signals back to the posterior lobe of the pituitary to produce more oxytocin
This causes more intense and frequent uterine contractions
Ends once birth has controlled (uterus no longer has anything to contract on)