estrous cycle

Question 1

goal of the reproductive system

Answer 1

-optimize opportunity to become pregnant
- maintain pregnancy

Question 2

lordosis

Answer 2

• swayback
• posture changes because of heat

Question 3

estrus

Answer 3

time that female is sexually receptive and in standing heat

Question 4

estrous cycle

Answer 4

interval from one heat until the next

Question 5

estrous vs estrus

Answer 5

estrous (adjective) describes the cycle while estrus (noun) is standing heat

Question 6

what are the four stages to the estrous cycle

Answer 6

estrus
metestrus
diestrus
proestrus

Question 7

steps to estrus

Answer 7

1. high estradiol causes GnRH surge
2. LH surge
3. ovulation

Question 8

what is metestrus

Answer 8

ovulation to functioning CL

Question 9

what occurs in metestrus

Answer 9

• hormone levels low
• progesterone level starts to increase

Question 10

how long does metestrus last

Answer 10

1-5 days
- quick process

Question 11

in what stage is the CL fully functional

Answer 11

Diestrus

Question 12

What occurs in diestrus

Answer 12

• high levels of progesterone
• embryo develops in uterus

Question 13

if embryo develops in uterus during diestrus what occurs

Answer 13

no PGF2a being released from uterus so no luteolysis

Question 14

if no embryo in uterus what occurs

Answer 14

PGF2a causes CL to regress (luteolysis occurs)

Question 15

when luteolysis occurs, what happens to progesterone and inhibition

Answer 15

progesterone decreases
inhibition removed

Question 16

what has to happen for no follicle recruitment to occur

Answer 16

low levels of GnRH
low levels of LH and FSH

Question 17

how does the next generation of antral follicles become recruited

Answer 17

• progesterone levels decrease
• negative feedback to hypothalamus decreases
• GnRH levels increase

Question 18

when is the CL undergoing regression, or luteolysis

Answer 18

proestrus

Question 19

in what stage does the antral follicle develop

Answer 19

proestrus

Question 20

what occurs during proestrus

Answer 20

• progesterone levels fall
• switch from progesterone dominance to estradiol dominance
• female starts to become recpetive

Question 21

what does estradiol help with

Answer 21

preparing the uterus and oviducts for sperm transport and fertilization

Question 22

the estrous cycle is divided into how many phases and what are they

Answer 22

1. follicular phase
2. luteal phase

Question 23

what is the follicular phase

Answer 23

• begins with Cl regression
• ends with ovulation of mature dominant and ovulatory follicles

Question 24

what is the predominant hormone used in the follicular phase

Answer 24

estradiol

Question 25

what are the two substages of follicular phase

Answer 25

1. proestrus- CL regression to heat 2. estrus- sexual receptivity

Question 26

what is the luteal phase

Answer 26

formation of the CL after ovulation until CL regresses

Question 27

in what phase is the CL most functional

Answer 27

luteal

Question 28

what is the main hormone for the luteal phase

Answer 28

progesterone

Question 29

what are the substages of luteal phase

Answer 29

1. metestrus- transition period following ovulation until CL functional 2. diestrus- CL is functional and longest stage