Repro Final

Human Reproduction (Chapter 16)

What is the importance of reproductive physiology to our future?

• Feeding people and increasing the human population

• Improved reproductive health in poor nations

• improved mental health for infertile couples

Luteolysis in primates

Uterus is not needed

Source of luteolytic PGF2a in women

Ovary (short distance to travel)

Duration of sperm viability in women’s tract

5-6 days

Copulation within how many days of ovulation can result in pregnancy?

5-6 days

Probability of conception in 1 cycle?

0.33 (30%)

What are the three classifications of Birth Control?

1. Contraception- Opposing conception- prevents fertilization

2. Interception- prevents implantation; embryo formed

3. Abortion- embryo or fetal disruption; after implantation

What is steroidal contraception classified as?

Both contraception and interception

What is the failure rate of implantation for couples trying to have a baby?

25%

What is the primary active ingredient in steroid contraception?

Progestin- any natural or synthetic material that has P4-like actions

What are the methods of delivery and length of effectiveness for steroid contraceptives

1. Oral/pill -daily

2. Patch - weekly (steroids diffuse easily through skin/barrier

3. Vaginal Ring - monthly (CIDR)

4. Injection (IM) - every 90 days

5. Intrauterine devices (IUD) - years

6. Implant (SQ) - years

What hormones are used in the pill?

P4 and E2

What method of contraception is best for underdeveloped countries?

Longest lasting

Why is E2 added to the pill?

Promotes normal reproductive tract function. In small amounts it has negative feedback→ FSH/LH

When did the FDA approve the first oral contraception?

June 23rd, 1960 — Enovid

What stimuli are involved in reproduction?

• tactile

• olfactory

• auditory

• visual

Where does fertilization occur?

The ampulla of the oviduct

What is the maternal recognition hormone in farm animals?

• Bovine IFN-t

• ovine IFN-t

• estradiol

AMH

anti-mullerian hormone. Causes free-martinism

How does the menstrual cycle differ from the estrous cycle?

1. endometrial sloughing (menses) occurs in a predictable manner during every cycle if the women is not pregnant

2. no defined period of sexual receptivity

What are the six events of the menstrual cycle?

1. Menstruation

2. follicular growth

3. ovulation

4. corpus luteum formation and growth

5. endometrial growth and secretion

6. luteolysis

Follicular growth

Follows menses. Takes place in response to FSH and LH from the anterior pituitary gland

Ovulation

Occurs around day 14.

Corpus Luteum formation

Follows ovulation. CL secretes progesterone and some estrogen, promote endometrial growth

Luteolysis

Follows CL formation if women is not pregnant. Takes out the CL. No more progesterone is produced triggering onset of menses.

Ovarian Cycle

Changes that occur in the ovary during the cycle

Uterine Cycle

Changes that occur in the endometrium of the uterus during the cycle.

Follicular phase

follicular growth during and following menstruation. Because the dominant structures in the uterus are the follicles. Dominant hormone is E2. FSH and LH are secreted as well.

Luteal phase

Begins after ovulation. dominant ovarian structure is the corpus luteum and the dominant hormone is progesterone.

Premenstrual Syndrome (PMS)

symptoms caused by the rapid drop in progesterone

LH

Hormone that spikes immediately before ovulation, but is low the rest of the menstrual cycle.

Progesterone

Hormone from the CL, high during the luteal phase of the menstrual cycle and during pregnancy. Also causes negative feedback on GnRH release.

Estradiol

Hormone that spikes before ovulation, and midway through the luteal phase of the menstrual cycle.

FSH

Hormone that has a small spike before ovulation but is low the rest of the menstrual cycle.

The greatest number of oocytes in the human ovary comes at which time of development for the female?

Mid-gestation

Preovulatory follicle

Produces estradiol to induce lordosis

Corpus Luteum

indirectly keeps the female out of estrus

Dominant follicle

will not ovulate because the CL is present

Body of the epididymis

Sperm gain motility

Tail of the epididymis

Launchpad for ejaculation

For the 7-day CIDR protocol, what day would a heifer that was on day 5 of her cycle at the time of CIDR placement be at the time of CIDR removal?

Day 12

Day 0 of the menstrual cycle

Menses

Day 7 of the menstrual cycle

P4 low

Day 14 of the menstrual cycle

ovulation

Day 21 of the menstrual cycle

P4 high

What makes up the spermatic cord?

1. Testicular artery- brings blood to the testes

2. Pampiniform plexus- takes blood away from the testes

3. Ductus Deferens- Carries sperm away from the testes

4. Cremaster muscle- contracts and relaxes to increase blood flow in the pampiniform plexus, raises testes up for a short time during fight or flight

What is the difference between the estrus period and the estrous cycle?

Estrus- time of sexual receptivity

Estrous- entire cycle

Interfeuron-tau

Interferes with CL regression

What species go all gestation with their CL?

Doe and Sow

What hormone goes down within 1 week of parturition?

P4- CL regresses

What hormones increases within 1 week of parturition?

• E2

• Fetal cortisol

• PGF2a-regresses the CL

Spermatogenesis

Starts in the lumen of the seminiferous tubules as:

1. Leydig cells

   1. Basement membrane

2. spermatogonia

3. 1* spermatocyte

4. 2nd Spermatocyte (1N)

5. round spermatid

6. flat spermatid

7. sperm cell

End

• Sertoli cells support developing cells ABOVE the basement membrane

• Spermatogonia replicate on the basement membrane

Four stages of the estrous cycle

1. Proestrus

   1. E2 high

   2. P4 low

2. Estrus

   1. E2 high

   2. P4 low

3. Metestrus

   1. E2 low

   2. P4 high

4. Diestrus

   1. E2 low

   2. P4 high

• Proestrus and Estrus are part of the follicular phase

• Metestrus and Diestrus are part of the luteal phase (80%)

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