Repro Final Flashcards by Jennifer Lyons

In 1677, Anthony van Leeuwenhoek described spermatozoa. What was instrumental for this to occur?

Microscope

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Name the tubule/ductile that transports spermatozoa from the testis into the epididymis.

Efferent ductiles

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Indicate 3 roles for epididymis.

Nourish
Allow sperm to mature
Storage depot

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Indicate the hormones secreted and regulatory direction in the feedback loop.

Hypothalamus
GnRH(+)
Anterior Pituitary
LH(+)                       FSH(+)
Leydig cells     and Sertoli cells

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Define/describe spermatogenic cycle and spermatogenic wave.

Spermatogenic cycle: Measure of time at a certain point of the cycle
Spermatogenic wave: Measure of distance of the tubule from round spermatid to round spermatid

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At the time of ejaculation, have spermatozoa undergone a.) meiosis and b.) capacitation ?

Spermatozoa has undergone meiosis, but not capacitation.

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3 steps of spermatogenesis:

) Proliferation
) Meiosis
) Differentiation

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If you castrate a male, would you expect luteinizing hormone (LH) to increase or decrease. Why?

Increase! You remove the leydig and sertoli cells, so therefore you remove the (-) feedback and the body doesn’t stop making.

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What is the role for the golgi apparatus within the differentiating spermatid?

The GA ends up folding itself over the nucleus which eventually leads to the acrosomal cap for the sperm.

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Contractions of the uterus are important to facilitate movement of male germ cells through the female reproductive tract. Is the oviduct also a contractile organ?

Yes!

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Explain the acrosome reaction.

Acrosin is involved. The acrosome reaction (when induced) allows the sperm to pass through the acrosome and digest into the zona pellucida of the oocyte for eventual DNA dispersal.

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Name the 2 blocks to polyspermy that are induced by the cortical reaction.

The zona pellucida block - prevents sperm from reentering

The vitelline block - keeps selected sperm from exiting

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Are the cells of the 8-cell embryo considered totipotent? What does this mean?

Yes.

Totipotent = have all the DNA required to make the whole animal

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What is meant by the “cleavage” of the early embryo?

From 2-16 cells in mitotic division, there is a “cleavage”. At this stage, cells are considered totipotent.

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T or F: A primordial follicle contains a primary oocyte surrounded by the zona pellucida and a single layer of cuboidal granulosa cells.

False.

No ZP at primary and pregranulosa cells are flattened.

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At what stage of meiosis would the oocyte of a small antral follicle be arrested in?

Diplotene of prophase I

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How did scientists determine that pre-antral follicular development was NOT dependent on gonadotropins?

Removed blood supply.

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T or F: At the time of recruitment, granulosa cells express receptors for LH and theca cells express receptors for FSH.

False.
Theca: LH-R (doesn’t respond to FSH)
Granulosa: Both (after selection)

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Name the hormone that causes the recruitment of a cohort of follicles.

Follicle stimulating hormone (FSH)

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T or F: In a dominant follicle, the theca interna is steroidogenic and produces estradiol,

False.
Granulosa cells produce estradiol.
Theca interna: androstendione

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Steroid hormones are derived from…

Cholesterol

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Steroidogenic Acute Regulatory Protein (STAR protein) is important for the…

Cholesterol to be converted to androstendione in the theca interna.
Which is converted to estradiol by the granulosa cell.

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Name the hormone that induces regression of the corpus luteum and identify where it is produced.

Prostaglandin F2A secreted in the uterus

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3 extra-embryonic memrbanes.

) Amnion - surrounds embryo
) Allantois - vascular; attaches with chorion
) Chorion - outer

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Identify the 6 potential layers used to classify the maternal/fetal barrie.

1. ) Fetal endothelium 2. ) Fetal connective tissue 3. ) Fetal chorionic epithelium 4. ) Maternal endometrial epithelium 5. ) Maternal connective tissue 6. ) Maternal endothelium

T or F: In the ewe, placentation can be considered endotheliochorial.

False. | Epithelialchorial

What is the role for eCG during early pregnancy?

Acts as FSH, follicular development, luteal, and more CL for progesterone

Identify the tissue responsible for production of eCG and the species of animal producing it.

Equine (horse) endometrial cups

T or F: During a normal pregnancy, maternal blood pressure is significantly increased.

False

T or F: During pregnancy, the ability of maternal blood to coagulate decreases.

False

Identify the two components of a placentome (ewe or cow) and indicate which component is of fetal origin and which is of maternal origin.

Fetal cotelydon | Maternal caruncle

T or F: In the ewe, parturition occurs in response to activation of the maternal hypothalamic/pituitary/gonadal axis.

False | Humans - placental

At parturition in the ewe, what causes the release of oxytocin from the maternal posterior pituitary?

Pressure sensors in the cervix

Puberty in the ewe lamb can occur as early as 5-6 months of age. Farmer Bob in southern KY had his ewes lamb last October. When should he expect these ewe lambs to reach puberty?

12-13 months later or around the October because they are seasonal breeders that respond to day length.

What gland produces the hormone melatonin?

Pineal gland

Farmer Bob's cousin Billy decided to raise swine. He purchase 20 infant gilts and one mature boar to start his operation. They were all housed in close proximity to one another. Puberty typically occurs in gilts around 28 weeks of age. At what age should Billy expect his 20 gilts to reach puberty?

24 weeks due to the presense of the mature boar

In the ewe, estradiol and progesterone exert negative feedback on the hypothalamic/pituitary/gonadal axis. During periods of anestrus, what is the effect of a.) estradiol and b.) progesterone on the pattern of secretion (pulse amplitude and pulse frequency) of LH.

a.) E2 and b.) P4 DECREASE pulse frequency during anestrus.

In males, Sry is considered the testis determining factor. Sry will activate...

SF1

T or F: Men typically have 44 autosomes plus 2 sex chromosomes (XY). When a male is born with an additional Y chromosome (XYY), it is expected that he will be of normal fertility.

True.

T or F: During sexual differentiation in males, fetal leydig cells secrete testosterone. This testosterone induces degeneration of the Mullerian ducts.

False. | Wolffian

During sexual differentiation, what cells produce anti-mullerian hormone?

Sertoli cells

The male prenatal brain is masculinized by _____.

Estradiol and DHT

Describe the role of alpha-fetoprotein with respect to prenatal brain development.

Alpha-fetoprotein causes estradiol to prevent masculinization of the brain.

T or F: The corpus luteum secretes progesterone to relax the uterine endometrium.

False. P4 secreted by the uterus. Relax the uterine myometrium.

T or F: During luteinization, granulosa cells differentiate into large luteal cells.

True.

T or F: Prostaglandins are derived from the precursor cholesterol.

False. | Derived from arachidonic acid.

T or F: Capacitation of spermatazoa occurs in the epididymis.

False. | Occurs in the vagina.

T or F: Cyclooxygenase-2 (COX-2) is essential for ovulation.

True. | COX-2 required to make prostaglandins.

Describe the process of maternal recognization in the pig. Include reference to the critical period, signal and biological response.

In the sow, maternal recognition begins at 12-13 days with the signal of estradiol. Estradiol redirects PGF2a into the lumen of the uterus, away from the ovary. If this did not happen, PGF2a would regress the corpus luteum within the ovary. Corpus luteums are important for maintaining pregnancy.

Describe the process of luteal regression in the ewe.

Luteal regression is possible by direct contact of PGF2a with the corpus luteum by way of the ovarian artery to avoid the lungs.

You own a herd of 50 beef heifers. All are currently cycling. You need to synchronize them for artificial insemination. Describe how you would do so.

The point to control: Ovary's corpus luteum Step 1: Place CIDR which acts as the CL artificially through the use of P4. This prevents ovulation. Step 2: After 7 days, remove CIDR and give a shot of PGF2a which will regress any CLs that are actually present. At this point, about 2/3 of my heifers are in sync. Step 3: After 11 days, give second shot of PGF2a to kill any other CL present in the cycle. All of herd should be in sync. Step 4: After 36 hours, give GnRH which controls timing by inducing an LH surge to begin ovulation.

What is the different between a gilt and a sow?

Gilt - has not given birth | Sow - has given birth

If I performed a hysterectomy and removed both uterine horns from a cycling, non-pregnant ewe on day 9 of the estrous cycle, for how long would the CL be maintained on the ovary?

CL maintained for length of gestation. In a ewe, about 145 days.

What is the difference between the luteal phase and the follicular phase of the estrous cycle?

Luteal phase - CL present | Follicular phase - No CL present

Where does fertilization occur?

In the oviduct, specifically above the ampullar-isthmus junction

Describe the H/P/G feedback loop during the luteal phase.

``` Hypothalamus (-)GnRH Anterior Pituitary (-)LH Corpus Luteum P4 to Hyp (-) --> ```

Describe the H/P/G feedback loop during the follicular phase.

``` Hypothalamus (-)GnRH Anterior Pituitary (-)FSH/LH Pre-ovulatory follicle E2 to both (+) --> ```

Name the major proteolytic enzyme released from the acrosome of the spermatozoa.

Acrosin

Name 2 key processes in ovulation.

1. Differentiation | 2. Luteinization

Name the critical signal (hormone) responsible for maternal recognition of pregnancy in women.

hCG (what you are looking for when you pee on a stick)

Does hCG have mainly FSH- or LH-like bioactivity?

LH-like bioactivity

How long is the ovulatory cascade (the time from the LH surge to rupture the follicle and expulsion of the cumulus-oocyte complex in the cow?

30 hours

T or F: In the female, Wolffian ducts develop into the uterus, oviducts and anterior vagina.

False. | Wolffian from T4

T or F: In the male, Wnt4 activates/induces the testis determining factor known as Sry.

False | SOX-9

T or F: Primordial germ cells originate in the genital ridge.

False

T or F: A male with an extra X chromosome is expected to be of normal fertility.

False. | Klinefelter's

T or F: A female with an extra X chromosome is expected to be of normal fertility.

True. | Trisomy X

AMH regresses...

Mullerian ducts

Testosterone stimulates...

Wolffian ducts

Describe how/why the fetal female brain is not masculinized.

Alpha-fetoprotein binds to estradiol which prevents estradiol from reaching the brain where it would masculinize it.

T or F: During seasonal anestrus in the ewe, estradiol will decrease the pulse amplitude of LH released by the anterior pituitary.

False. | Pulse frequency during anestrus.

T or F: During seasonal anestrus in the ewe, P4 will decrease the pulse amplitude of LH released by the anterior pituitary.

False. | Pulse frequency during anestrus.

T or F: The secretion of serotonin by the pineal gland is the primary regulator of seasonal anestrus in the ewe.

False. | Melatonin

T or F: Puberty in the heifer calf is expected to be delayed if that animal is reared on a low plane of nutrition.

True.

Identify 4 permissive signals that can affect the onset of puberty.

1. Metabolic status/Body weight 2. Social interactions 3. Demographics (sex ratio, presence of male) 4. Seasonal repro/Physical environment

When discussing puberty, what is meant by the "developmental clock"?

Maturation of the H/P/G axis | *Permissive factors affect it, but still have to reach maturation first.

T or F: The gonadostat hypothesis equates the changes that occur in feedback at puberty to a resetting of the hypothalamic/pituitary/gonadal axis "thermostat".

True

Metritis is the inflammation of..

Endometrium AND myometrium

Endometritis is the inflammation of..

Endometrium and glandular tissue only

Causes that can lead to the inflammation of the uterus

1. Venereal (Ex: Bull can transmit STD) 2. Post-calving 3. Systemic infection could target uterus

Is semen from a stallion routinely shipped chilled or frozen?

Chilled

You have an ovariectomized mare that you want to use as a "teaser" to stimulate a stallion. What hormone would you treat her with to accomplish this?

Estrogen

Endometriosis is...

Where endometrial tissue is growing outside of the uterus.

Name the 3 defininf criteria of polycystic ovarian syndrome (PCOS) in women. Indicate how many of these criteria must be met to be diagnosed as having PCOS.

1. Androgenemia 2. Anovulation (ovulation dysfunction) 3. Polycystic ovaries 2/3 must be met

A heifer has a large, estrogenic follicular cyst. If I compared the relative expression of mRNA for Angiotensin in tissue collected from this cyst versus an estrogenic dominant follicle, would I expect to see a difference?

Yes

A heifer has a large, estrogenic follicular cyst. If I compared the relative expression of mRNA for Indian hedgehog protein precursor in tissue collected from this cyst versus an estrogenic dominant follicle, would I expect to see a difference?

Yes

A heifer has a large, estrogenic follicular cyst. Would I expect to see a difference in steroidogenesis among small follicles (3-5mm in diameter) that were present on the same ovary of this animal?

Yes

A heifer has a large, estrogenic follicular cyst. Would I expect to see a difference in steroidogenesis among large follicles (10-15mm in diameter) that were present on the same ovary of this animal?

No - all hormones constant

What is accepted as the general or overall mechanism that causes cystic ovarian disease in cattle? Two potential causes?

Dysfunction of the H/P/G axis Two potential causes: 1. LH surge 2. E2 feedback

Both hCG and GnRH are effective at treating ovarian cysts in cattle. Without considering cost, what is the primary reason why GnRH ,and not hCG, is the preferred choice for the treatment of these cysts?

hCG is human-induced and would be less likely to work/have more problems associated with it than GnRH

What is spinnbarkeit?

Elasticity of cervical mucus | -Influenced by E2