6.6: Reproduction

Henry Behre

6.6.1: Draw and label diagrams of the adult male and female reproductive

systems

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

REVIEW! Correct Answer = CANDY

Which organ secretes FSH?OvaryTestisPituitary GlandPlacenta

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

Testis!

How does fertilization differ from copulation?

Fertilization always produces a zygote

Only fertilization involves gametesFertilization is a conscious eventFertilization can spread HIV

Fertilization always produces a zygote!

Copulation: the act of having sexual intercourse

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

Estrogen Progesterone

LH FSH

A) High Low High High

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)

11.4: Reproduction Review! More candy….

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

Location Function

A Seminiferous tubule

Feeding developed sperm

In the menstrual cycle in humans, which hormone causes the wall of the follicle to

develop after ovulation and to secrete more progesterone?

EstrogenFSHLHOxytocin

LH (Leutenizing Hormone)

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)