Exam 3 Lecture Notes

Question 1

estrus

Answer 1

Recurring period of sexual receptivity and fertility in many female mammals. During estrus, the female is in heat, indicating that she is ready to mate and can conceive.

Question 2

what is estrus greek for?

Answer 2

frenzy

Question 3

estrous

Answer 3

a period of sexual receptivity is determined by the interval from one estrus to the next

Question 4

estrous cycle length: cow

Answer 4

21 days

Question 5

estrous cycle length: ewe

Answer 5

16 days

Question 6

estrous cycle length: sow

Answer 6

21 days

Question 7

estrous cycle length: mare

Answer 7

21 days

Question 8

when should you breed most animals?

Answer 8

when they are in heat

Question 9

follicular phase

Answer 9

follicle growth, Graafian follicle forms

Question 10

what happens to the follicle during estrus?

Answer 10

ovulation occurs

Question 11

luteal phase

Answer 11

the corpus luteum is present

Question 12

understand how blood flow is affected by the estrous cycle

Answer 12

blood flow goes down during estrus and then will increase during the luteal phase

Question 13

understand how hormones are changed during the estrous cycle

Answer 13

estrogen increases before estrus, LH surge during estrus so ovulation can occur, FSH increases at the same time as LH, progesterone decreases during estrus and then increases after esturs (when the CL is formed), PGF2a increases before estrus to regress the CL

Question 14

Hormonal Control of the Estrus Cycle

Answer 14

(diagram)
1. hypothalamus releases GnRH to the anterior pituitary
2. FSH and LH is released from the anterior pituitary and goes to the follicle
3. estrogen is produced by the follicle and goes to the hypothalamus, uterus, and anterior pituitary
4. the anterior pituitary released LH which goes to the follicle (ovulation occurs) and corpus luteum (form the CL)
5. CL produces progesterone which goes to the uterus, hypothalamus, and uterus
6. the uterus releases prostaglandin which will regress the CL

Question 15

menses

Answer 15

menstruation (endometrial sloughing)

Question 16

follicular phase of the menstrual cycle

Answer 16

menses (5 days) plus the proliferative phase (5 days)

Question 17

luteal phase during the menstrual cycle

Answer 17

secretory phase (14 days), CL present

Question 18

________ us needed for cycling, without it no cycling would occur (how seasonal animal stop cycling out of season)

Answer 18

GnRH

Question 19

the estrous cycle: estrogen

Answer 19

high during heat, the animal will show signs of estus

Question 20

___________ has a positive feedback mechanism to make LH surge

Answer 20

estrogen

Question 21

the estrous cycle: LH

Answer 21

ovulation hormes, a surge of LH causes ovulation to occur

Question 22

the estrous cycle: CL

Answer 22

produces progesterone, forms where the oocyte ovulates from

Question 23

what happens to the CL if pregnancy occurs? What happens to the CL if there is no pregnancy?

Answer 23

if pregnant the CL will be maintained, if not pregnant PGF2a is released and luteolysis occurs which will degrade the CL

Question 24

___________ declines which allows estrogen to increase for signs of heat and ______ will surge and ovulation can occur

Answer 24

progesterone, LH

Question 25

luteal phase

Answer 25

CL present

Question 26

follicular phase

Answer 26

follicle is dominant, present

Question 27

the menstrual cycle: menses

Answer 27

shedding of the endometrial lining (about 5 days)

Question 28

the menstrual cycle: proliferative phase

Answer 28

the endometrial lining will begin to grow back

Question 29

why does there have to be an endometrial lining created before ovulation?

Answer 29

the lining must be present for the embryo to implant, without it the embryo cannot implant

Question 30

the menstrual cycle: secretory phase

Answer 30

hormones are being released after ovulation, progesterone is high

Question 31

what happens to progesterone if pregnancy occurs? what happens is pregnancy does not occur?

Answer 31

high progesterone (present CL) is ready for pregnancy and no pregnancy means that there is no CL which means there is no progesterone which causes menses

Question 32

the menstrual cycle: follicular phase

Answer 32

follicle growth (1/2 of the cycle)

Question 33

the menstrual cycle: luteal phase

Answer 33

CL is present (1/2 of the cycle)

Question 34

spiral arteries

Answer 34

arteries within the endometrial lining, ensured that after sloughing the woman does not bleed out

Question 35

estrous vs menstral cycle: follicular phase

Answer 35

- estrous: short (20% of the cycle) - menstrual: long (50% of the cycle)

Question 36

estrous vs menstral cycle: ovulation

Answer 36

- estrous: beginning and end (day 0 and 21) - menstrual: middle (day 14)

Question 37

estrous vs menstral cycle: luteal phase

Answer 37

- estrous: 80% of the cycle - menstrual: 50% of the cycle

Question 38

estrous vs menstral cycle: fertile phase

Answer 38

- estrous: 24 hours or less - menstrual: up to 6 days before ovulation

Question 39

estrous vs menstral cycle: endometrial sloughing

Answer 39

- estrous: NONE - menstrual: after luteolysis

Question 40

estrous vs menstral cycle: luteolysis | what hormone causes it? and where does it come from?

Answer 40

- estrous: uterine PGF2a - menstrual: ovarian PGF2a

Question 41

estrous vs menstral cycle: sexual receptivity

Answer 41

- estrous: well defined - menstrual: relatively uniform

Question 42

estrous vs menstral cycle: progesterone function and sexual receptivity

Answer 42

- estrous: inhibits GnRH release inhibiting sexual activity - menstrual: inhibits GnRH but does not influence sexual receptivity

Question 43

estrous vs menstral cycle: menopause

Answer 43

- estrous: NONE - menstrual: well characterized

Question 44

estrous cycle vs the menstrual cycle

Answer 44

- the follicular phase is short in estrous and long in menstrual - the ovulation occurs at the beginning and end of estrous and in the middle of menstrual cycle - the luteal phase is 80% of the cycle in estrous and 50% of the menstrual cycle - the fertile period of the estrous cycle is 24 hours or less and the menstrual cycle. is up to 6 days before ovulation - endometrial sloughing does not occur in the estrous cycle but occurs after luteolysis in the menstrual cycle - luteolysis occurs due to uterine PGF2a in estrous and from ovarian PGF2a in the menstrual cycle - sexual receptivity is well defined in estrous and relatively uniform in menstrual cycle - progesterone function and sexual receptivity inhibits GnRH release inhibiting sexual activity in estrous and in the menstrual cycle progesterone inhibits GnRH but does not influence sexual receptivity - menopause does not occur in estrous and is well characterized in menstrual cycle

Question 45

corpus luteum formation

Answer 45

1. hypertrophy of granulosa and theca cells 2. folding of follicular wall 3. breakdown of the basement membrane 4. pushing of cells towards the center 5. angiogenesis 6. lutenization

Question 46

angiogenesis

Answer 46

formation of new blood vessels (in the CL)

Question 47

4 steps of angiogenesis

Answer 47

1. basement membrane breakdown 2. production of angiogenic factors by granulosa cells 3. mitosis and migration of endothelial cells 4. capillary tube formation

Question 48

CL classification (3 types)

Answer 48

- corpus hemorrhagicum - corpus luteum - corpus albicans

Question 49

corpus hemorrhagicum

Answer 49

- blood, red color - occurs after rupture

Question 50

corpus luteum

Answer 50

- mature CL - yellow color - lutenization occurs

Question 51

corpus albicans

Answer 51

- white color - before degradation

Question 52

when no pregnancy occurs __________ will regress the CL

Answer 52

PGF2a

Question 53

CL Functions

Answer 53

- produce progesterone (and oxytocin) - requirement for the maintenance of pregnancy - stimulates mammary development - controls the ovarian cycle (inhibit ovulation and estrus)