NAME ______________________________

This examination is conducted on the honor system. The printing or signing of your name above pledges you to neither give nor receive assistance with this exam. Disregarding this pledge will result in a grade of zero (0) for this examination.

Put the most appropriate answer in the allotted space for full credit. Be specific, concise, yet complete. READ ALL QUESTIONS CAREFULLY AND GOOD LUCK!

Question Credit Credit Given

I. 16 _____

II. 20 _____

III. 16 _____

IV. 8 _____

V. 20

VI. 20 _____

TOTAL ______

_____1. In short-day breeders, an increase in the dark period results in increased melatonin release by the pineal gland.

_____2. Progressive sperm motility is highly correlated with male fertility while other sperm viability parameters are not.

_____3. Unilateral hysterectomy ipsilateral to the corpus luteum results in premature CL regression.

_____4. During spermiogenesis, the distal centriole gives rise to the axoneme of the flagellum.

_____5. The zona pellucida is an extracellular matrix of hyaluronic acid which is laid down around the oocyte by surrounding cumulus cells.

_____6. In the testis, receptors for LH are found only on Leydig cells while Sertoli cells have receptors for both FSH and testosterone.

_____7. The flehman response in males facilitates concentration of pheromonal substances by the vomeronasal organ.

_____8. Viagara facilitates erection by prolonging the vasodilatory effects of nitric oxide.

 

II. Fill in the blanks with the most appropriate word or phrase. (20).

1. Estradiol production by the dominant follicle is dependent upon ___________________ receptors on the theca interna and ___________________ receptors on the granulosa cells.

2. Maximal contractions of the myometrium occur during the ___________________ phase of the estrous cycle while endometrial secretions are highest during the ___________________ phase.

3. After the LH surge, production of progesterone by the dominant follicle results in ___________________ production by the theca interna leading to formation of a ___________________ in the follicle wall.

4. Two examples of induced ovulators are the ___________________ and the ___________________.

5. Luteal cells are derived from ___________________ and ___________________ cells of the Graafian follicle.

6. Luteolytic levels of PGF_2α are released from the endometrium in response to increased release of ___________________ from the corpus luteum and increased synthesis of ___________________ receptors in the endometrium.

7. The positive feedback of ___________________ when circulating progesterone is low leads to a surge in ___________________ from the anterior pituitary and ultimately ovulation.

8. During the process of follicle selection when ovulatory follicles emerge, an increase in ___________________ production by the follicles causes a decrease in ___________________ from the anterior pituitary.

9. ___________________ junctions which form between cumulus cells and the oocyte permit the transfer of substances which inhibit ___________________ prior to the LH surge.

10. During the estrous cycle in cattle, 2-3 follicular _______________ occur in which one follicle achieves _______________ and most others undergo atresia.

III. Semen processing. Fill in the blanks with the most appropriate word or phrase. (16).

The two main properties of the artificial vagina which are important for stimulating ejaculation by males are ___________________ and ___________________. Media for initial dilution and immediate use of semen (sperm) should be isotonic with semen and sperm to prevent ___________________, should contain a ___________________ to maintain neutral ___________________, and include a metabolizable substrate such as ___________________. Because of the ___________________ nature of sperm metabolism, short term storage requires cooling in medium containing ___________________ or ___________________ to prevent cold shock. The most common cryoprotective agent used for semen freezing is ___________________ which prevents damage due to ___________________ formation and elevated ___________________ concentration. In the United States, bull semen is packaged in ___________________ with a ___________________ milliliter capacity, frozen in the cold vapor above ___________________, and stored indefinitely in ___________________.

Seasonally polyestrus –

Follicle recruitment –

Corpus hemorrhagicum –

Acrosomic vesicle –

Mitochondrial helix –

Angiogenesis –

Luteolysis –

Manchette -

A. On the graph, draw the profile for circulating LH and progesterone during the estrous cycle. Also indicate the timing and pattern of PGF_2α secretion. Indicate with "0" the day of estrus, with "X" the day of CL regression, and with a "√" the day of ovulation.

You are provided with 4 normally cycling cows as follows:

B. Which cows will have a synchronized estrous cycle at the completion of the following treatments (list by Cow #)?

Single injection of PGF_2α –

Two injections of PGF_2α 5 days apart –

Two injections of PGF_2α 11 days apart –

P.R.I.D. for 10 days then removed –

P.R.I.D. for 7 days then removed w/ PGF_2α on day 6 –

C. What stage of the estrous cycle will the synchronized cows be in 48 hours post-treatment?

D. P.R.I.D. is an abbreviation for what device?

E. Synchronized cows will come into estrus 3, 5, or 7 days post-treatment (circle correct response)?

Peritubular cell

Basement membrane

Spermatogonium

Spermatocyte

Spermatid

Cytoplasmic bridges

Sertoli cell

Sertoli cell junction

Blood-testis barrier

Basal compartment

Adluminal compartment

Spermatocytogenesis

Meiosis

Spermiogenesis

Golgi and cap phase

Acrosomal and maturation phase

Spermiation

Residual cytoplasm

Cycle

Stages

Wave