Ovarian Cyclicity

Question 1

7 things reproductive cyclicity can be influenced by?

Answer 1

Puberty Sexual maturity Breeding season Estrous cycle Postpartum sexual activity Aging Environment, nutrition and genetic

Question 2

What is estrous cycle?

Answer 2

Series of reproductive events starting with the estrus (heat) and ending at the subsequent estrous

Question 3

Why do females have multiple estrous cycles?

Answer 3

Multiple opportunities to get pregnant in a yr

Question 4

3 types of estrous cycle and species which undergo each

Answer 4

Polyestrus (multiple cycles/yr) -Cow, queen, sow, rodent Seasonal Polyestrus - Mare (long day) - Ewe (short day) Monestrus - Dog, wolf

Question 5

4 stages of estrous cycle

Answer 5

1. Proestrus (formation of ovulatory follicle) 2. Estrus (sexual receptivity and peak of estradiol secretion) 3. Metestrus (CL formation and Progesterone secretion) 4. Diestrus (high progesterone secretion)

Question 6

3 things which occur in Proestrus period?

Answer 6

1.Decrease in progesteron 2. Degredation of CL 3. Increase in estradiol

Question 7

What is heat dependent upon?

Answer 7

Max production of estradiol

Question 8

What occurs during diestrus?

Answer 8

1. CL becomes fully developed 2. Plateau of progesterone 3. Minimum amount of estradiol

Question 9

What is lacking in anestrus?

Answer 9

No presence of ovulatory follicles or corpus lutea

Question 10

What is anestrus a result of?

Answer 10

Insufficient release of GnRH

Question 11

What can cause anestrus?

Answer 11

Pregnancy Lactation Presence of offspring Season Stress

Question 12

Explain Seasonal anestrus

Answer 12

Lots of light Increase firing of retinal nerves Excitation of Superior Cervical Ganglion Inhibition of pineal gland Decrease in melatonin Decrease in GnRH Decrease in FSH and LH Results in anestrus

Question 13

Explain gestational anestrus

Answer 13

CL and or Placenta maintain high levels of progesterone High P4 reduces GnRH secretions

Question 14

Explain silent ovulation

Answer 14

Brain does not sense the first ovulation after anestrus (ewe)or gestation (cow) so no heat signals are given by cow to bull. Pregnancy can occur through AI. Luteal phase exists and P4 primes the brain but still no behavioral estrus. The 2nd follicular phase causes behavioral estrus

Question 15

Explain the influence of lactation on offspring

Answer 15

As # of suckling sessions/day increase blood LH is suppressed and anestrus occurs

Question 16

What are menses defined as?

Answer 16

The sloughing of the endometrium to the exterior

Question 17

What is the menstrual cycle divided into?

Answer 17

Two phases Non-luteal Luteal

Question 18

What is the non-luteal phase broken down to? and How long do they last?

Answer 18

Menses (5days) Proliferative Phase (9 days)

Question 19

How long is the luteal phase?

Answer 19

14Days

Question 20

Comparison between estrous and menstrual cycle

Answer 20

1. No define period of sexual receptivity in menstrual cycle 2. Menstrual cycle has menses 3. Different onset period between estrous and menstrual cycle