CH 7 Reproductive Cyclicity

Question 1

What happens to female (in general) at puberty?

Answer 1

Female enters state of reproductive cyclicity

Question 2

What does the estrous cycle do?

Answer 2

Provides female with repeated opportunities to become pregnant

If conception occurs, then female enters period of anestrus during pregnancy which ends after parturition, uterine involution and lactation

Question 3

What is estrus?

Answer 3

“standing heat” –> period of sexual receptivity

Question 4

What is the estrous cycle?

Answer 4

Period from 1st estrus to the next

Question 5

Polyestrus

Answer 5

uniform distribution of estrous cycles throughout the entire year

Question 6

Seasonally polyestrous

Answer 6

“clusters” of estrous that occur during certain seasons

Question 7

What animal is a short-day breeder?

Answer 7

sheep

Question 8

What animal is a long day breeder?

Answer 8

horses

Question 9

Monoestrus

Answer 9

Only one estrous cycle per year

Periods of estrus last for several days

Question 10

What are the 2 phases of the estrous cycle?

Answer 10

1. Follicular phase
2. Luteal phase

Question 11

What is the follicular phase (including structure and hormone)?

Answer 11

Period of regression of CL to ovulation
Generally short, <20% of cycle

Structure: follicle
Hormone: estradiol

Question 12

What is the luteal phase (including structure and hormone)?

Answer 12

Period from ovulation to CL regression
Very long, ~80% of cycle

Structure: CL
Hormone: progesterone

However, follicles do continue to grow during this phase

Question 13

What are the 4 divisions of the estrous cycle?

Answer 13

1. proestrus
2. estrus
3. metestrus
4. diestrus

Question 14

Proestrus

Answer 14

formation of ovulatory follicles + E2 secretion

Question 15

Estrus

Answer 15

sexual receptivity + peak E2 secretion

Question 16

Metestrus

Answer 16

Sexual receptivity +CL formation + beginning of P4 secretion + peak E2 secretion + ovulation follicular phase

Question 17

Diestrus

Answer 17

Sustained luteal secretion of P4

Question 18

When does proestrus begin and end?

Answer 18

period immediately before estrus

begins immediately when progesterone declines as a result of CL lysis and ends at the onset of estrus

Question 19

How long is proestrus?

Answer 19

2-5 days in length

Question 20

What hormones does proestrus switch from and to?

Answer 20

Switch from progesterone dominance to estradiol dominance

Question 21

What is homrone transition during proestrus due to?

Answer 21

The transition is due to FSH and LH

Question 22

What is estrus characterized by?

Answer 22

Visible behavioral symptoms such as sexual receptivity and mating

Question 23

What hormone is dominant during estrus?

Answer 23

Estradiol is dominant and at peak levels

Question 24

What is lorodosis?

Answer 24

Mating posture

Question 25

What happens during estrus?

Answer 25

Ovulation - for all species but cow which occurs during metestrus

Question 26

When does metestrus occur?

Answer 26

Period between ovulation and formation of functional CL

Question 27

What are hormone profiles during metestrus?

Answer 27

At start, E2 and P4 are relatively low. P4 levels increase over this period.

Question 28

When does diestrus occurs?

Answer 28

Period from formation of fully-functional CL (high P4) to lysis of the CL Longest stage of the estrous cycle

Question 29

What happens during diestrus?

Answer 29

Uterus prepares a suitable development and eventual attachment of the embryo to uterine endometrium

Question 30

How long does diestrus last?

Answer 30

usually 10-14 days in length

Question 31

Dog estrous cycle phases

Answer 31

Phases: proestrus, estrus, diestrus, and anestrus

Question 32

How many estrous cycles do wild canids go through?

Answer 32

1 estrous cycle/ year - usually seasonal

Question 33

How many estrous cycles do domestic dogs go through and when do they occur?

Answer 33

2 estrous cycles/year February - May

Question 34

What type of estrous cycles do cats have?

Answer 34

Polyestrous cycles - uniform distribution of estrous cycles that occur throughout the entire year

Question 35

What type of ovulators are felids?

Answer 35

Induced ovulators - copulation indices LH surge

Question 36

What is postestrus in cats?

Answer 36

Inerestrus period following estrus in queen that has not been induced to ovulate by copulation

Question 37

What happens if there is no copulation in cats?

Answer 37

No ovulation of CL formation. Thus, no metestrus or diestrus

Question 38

What is anestrus?

Answer 38

"without cyclicity" - ovaries remain inactive

Question 39

What can anestrus be caused by?

Answer 39

- pregnancy - lactation - the presence of offspring - season - stress - pathology

Question 40

What is the average menstrual cycle in women?

Answer 40

28 days

Question 41

What is menses?

Answer 41

sloughing of the endometrium to the exterior

Question 42

What is another name for anestrus in women?

Answer 42

amernorrhea

Question 43

What animals are polyestrus?

Answer 43

cow, queen, pig, rodents

Question 44

What animal(s) are long day seasonal polyestrus

Answer 44

horses

Question 45

What animals are short day seasonal polyestrus?

Answer 45

Ewe, doe, elk, nanny

Question 46

What animals are monoestrous?

Answer 46

dog, wolf, fox, bear

Question 47

What does the suckling stimulus do?

Answer 47

Blocks release of GnRH which then reduces LH to stimulate ovary follicular development

Question 48

What is the ram effect?

Answer 48

placement of male with females will decrease time to estrus. Especially important in ewe