Exam 2 REPRO PHYSIO

Can oogenesis happen without folliculogenesis

no

Reproduction

series of physiological and psychological events that must be properly timed

T/F: we can define reproduction as needing a functional male and a willing female

true

T/F: rate-limiting factor in farm animals, and most mammals is the male

false; it’s the female

What are the 2 breeding patterns in mammals (include examples of species for each)

1. once per cycle desire to mate (exhibit a standing heat)

   1. ex: domestic mammals

2. breed. whenever they want (Ab Libitum: At will)

   1. ex: humans and dolphins

[1.] is defined as standing heat, one event; [2.] is the progressive accomplishments of alterations in repro tract characterisitcs of estrus, metestrus, diestrus, and proestrus produced by changes in ovarian hormones, entire cycle

1. Estrus

2. Estrous Cycles

T/F: the structures on the ovary control what cycle female is in and how structure works

true

Breeding Exhaustion

point where male has mated too many times and is producing too few sperm to allow for a reasonable chance for pregnancy

What controls where a female is in her cycle

a) brain

b) muscles

c) structures on her mammary glands

d) structures on her ovary

d) structures on her ovary

T/F: Breeding Exhaustion is GREAT for optimizing repro/fertilization

false

List out the whole Estrous Cycle (hint: 4 phases)

proestrus → estrus → metestrus → diestrus

Do Estrous Cycles occur in non primate females

yes

T/F: The estrous cycle is the period from the beginning of estrus to the beginning of next estrus

true

Estrous cycles are the growth of [?], ovulation of [?] around the time of standing heat, and formation of a corpus luteum

---

a) hormones

b) follicles

c) corpus hemorrhagicum

d) P4

b) follicles

If the animal is NOT pregnant, the estrous cycle (will or will not?) start over

will

Cycles begin at [What]

• ovulation occurs in this phase

• start of cycle

• clear and observable signs in this phase

---

a) Estrus

b) Proestrus

c) Metestrus

d) Diestrus

a) estrus

T/F: Estrus and Estrous length varies bt species

true

Animals will ovulate during or just after estrus, the ovary will switch gears and go from growing follicles to creating [what]

---

a) more follicles

b) none of these

c) corpus luteum

c) corpus luteum

corpus hemorrhagicum, which is a major anatomical feature on ovary during what phase

metestrus

corpus luteum occurs in what phase

diestrus (longest phase of cycle)

If you see follicular growth on the ovary, what phase of the cycle is this

proestrus

Anestrus

(in some species) period bt diestrus and proestrus when nothing is happening

• NOT part of the cycle

• period when ovary and hormones are quiet like they were before puberty

Ewe

• length of cycle “estrous” :

• length of heat “estrus” :

• length of cycle “estrous” : 16-17 d

• length of heat “estrus” : 24-36 hrs

Goat

• length of cycle “estrous” :

• length of heat “estrus” :

• length of cycle “estrous” : 21 d

• length of heat “estrus” : 32-40 hrs

Sow

• length of cycle “estrous” :

• length of heat “estrus” :

• length of cycle “estrous” : 19-21 d

• length of heat “estrus” : 48-72 hrs

Cow

• length of cycle “estrous” :

• length of heat “estrus” :

• length of cycle “estrous” : 20-22d

• length of heat “estrus” : 18-24 hrs

Mare

• length of cycle “estrous” :

• length of heat “estrus” :

• length of cycle “estrous” : 19-25 d

• length of heat “estrus” : 4-7d

Days 17 to 21 of estrous cycle of cow is considered apart of what phase of cycle

proestrus (follicular)

which phase do these describe

• ovarian follicles are growing rapidly

• increase in estrogen secretion by growing follicles

• decrease in P4 from corpus luteum (CL)

• mucosal layers of vagina and uterus multiply

---

a) proestrus

b) anestrus

c) diestrus

d) none

a) proestrus

T/F: proestrus must occur first in order to have an ovulation

true

Proestrus begins as CL from previous cycle becomes atretic (closure), stops function → no more P4

What effect will this have

no more negative feedback on GnRH, FSH, LH → follicular development due to estrogen

in 3-4 days, some follicles go primary to secondary to tertiary, estrogen peaks which causes a transition from proestrus → ?

estrus

Diagram of Proestrus (I made this so chill)

Describe the uterine changes during proestrus

increase in number of cells in both the uterus and vagina, and uterus is in follicular phase

Estrogen during proestrus

mucus in uterus, vagina, and cervix will begin to thin out and become watery (helps sperm transport)

Estrous Cycle Diagram

What phase do the following characteristics describe

• period of sexual receptivity in female

• called heat

• first day of standing heat is day 1

---

a) proestrus

b) anestrus

c) diestrus

d) estrus

d) estrus

T/F: Estrus is the end of follicular phase

true

When does ovulation occur

during estrus or a few hours after it ends

Reproductive receptivity

time when female in estrus stands to be mated

Estrus induces behaviors conducive to what

a) sleeping

b) social bonding

c) mating

d) none

c) mating

T/F: estrogen-induced contraction will move the sperm away from the tract (AIJ- site of fertilization)

false: moves the sperm up to AIJ

Estrogens (during estrus) will lead to a surge of what 2 hormones

FSH and LH

LH surge triggers ovulation and begins transformation of theca and granulosa of follicle into what

P4-producing luteal cells of corpus luteum

T/F: (Estrus) Uterus will remain in follicular phase until ovulation

true

Diagram of Estrus that I made

Metestrus (luteal phase)

short transition period, within the luteal phase, that transforms repro system from estrogen dominated system to a P4 dominated system attempting to support a preg

after ovulation, ovary will enter what phase, while the uterus enters the secretory phase of development

luteal

after ovulation, follicle collapses into what structure, blood clot, non functioning

corpus hemorragicum

the blood clot (corpus hemo.) is replaced by functional cells, P4. By what day does the corpus hemorrhagicum transformed to corpus luteum

---

a) day 5

b) day 2

c) day 10

d) day 1

a) day 5

What phase are we in according to these characteristics

• P4 lvls rise and estrogen lvls drop

• repro tract is going quiet

• increasing P4 conc. induces tissues of endometrium to become organized and trigger them to produce products needed by embryo

• ex: cow, this will be period of ovulation, occuring a few hours after animal finishes standing heat

---

a) proestrus

b) diestrus

c) anestrus

d) metestrus

d) metestrus

the rising P4 occurring in metestrus causes a (positive or negative?) feedback on GnRH, FSH, and LH (esp LH)

negative feedback

Diagram of Metestrus that I made

what phase is during/start of day 1 of cycle

a) estrous

b) estrus

c) proestrus

d) none

b) estrus

what event triggers ovulation?

a) P4 rise

b) PGF2 alpha

c) none

d) LH surge

d) LH surge

T/F: metestrus and diestrus are in the luteal phase of the estrous cycle

true

What phase are we in according to these characteristics?

• longest period of estrous cycle in domestic species (short cycle animals lack this phase completely if NOT preg)

• rising or high lvls of P4

  • GnRH, FSH, LH inhibited

  • estrus inhibited

• maternal recognition signal must occur in this phase if animal is preg

  • maintains CL; CL of cycle to CL of preg

---

a) estrus

b) proestrus

c)diestrus

d) anestrus

c) diestrus

Maternal recognition

physiological recognition of preg, by female adults’ system due to a chemical signal from embryo

If there is no maternal recognition signal during diestrus, what hormone will be released (Hint: think of the main structure on ovary we need to get rid of)

a) Lactogen

b) GnRH

c) P4

d) PGF2 alpha

d) PGF2 alpha

(Diestrus) No maternal recognition signal → release of PGF2 alpha → regresses CL → what will happen in these species

• cow and pig

• horse and sheep

• cow and pig: goes into immediately into next proestrus (repeating cycles)

• horse and sheep: leave estrous cycle from diestrus and goes through anestrus period (anestrus occurs bt cycles)

Diagram of Diestrus that I made

What is occurring according to the following

• period bt diestrus and proestrus in monoestrous and seasonal polyestrous animals

• non-breeding season of ewe and mare

• varies in length

• quiet of repro tract

• ends when proestrus begins

• NOT a phase OF ESTROUS CYCLE

---

a) estrus

b) anestrus

c) luteal

d) ovulation

b) anestrus

Continuous Estrus

estrous animal w/ constant desire to mate and whose ovulation is triggered by act of mating

T/F: follicles are constantly developing then regressing → no luteal phase in continuous estrus

true

In diff types of estrous cycles, who does the continuous type occur in

rabbits and other induced ovulators

In continuous estrus cycles:

1. LH release is induced by [what?]

   • ovulation occurs 8-12 hrs after mating

2. act of mating sends a nervous impulse triggers [what?] surge (induced ovulation)

1. mating

2. LH

Induced ovulator means ovulation is triggered by what

act of mating

T/F: in induced ovulators:

• the nervous impulse, during mating, triggers LH surge

  • extremely high conception rates, sperm in tract same time as ovulation

true

Monoestrous

single cycle per year

• ex: bears, wolfs, foxes and many dog breeds

• single cycle → anestrus → single cycle

True polyestrous

• 2 or more estrous cycles per year UNLESS interrupted by preg

• composed of proestrus, estrus, metestrus, and diestrus merging into proestrus

what species are true polyestrous

cows and pigs

Seasonal polyestrous

• same as true poly. but last diestrus of breeding season would go into anestrus

• cycles are exactly like true polyestrous animals when in season

• out of season, complete the cycle with diestrus and go into anestrus (melatonin)

what species are seasonal polyestrous

sheep and horses

what are the 2 categories of polyestrous cycle?

a) true polyestrous and seasonal polyestrous

b) true polyestrous and false polyestrous

c) real polyestrous and fake polyestrous

d) true polyestrous and multiestrous

a) true polyestrous and seasonal polyestrous

Proposed mechanisms of seasonal polyestrous

• retina of eye is sensor for light signals

• impulses travel by way of optic nerve to pineal gland

• pineal gland releases melatonin

• melatonin serves as mediator bt photoreceptors, hypothalamus, and/or anterior pituitary

• episodic surges of LH occurs as breeding season begins

Postpartum estrus

estrus occurring within a few days after delivery

• rarely seen in cattle or sheep: they have extended postpartum anestrus period to allow repair of repro tract

Sow Heat

postpartum estrus ~3-10 days after farrowing, they rarely ovulate → cycle is sub or infertile

Foal heat

bt 5-15 days after foaling

• can ovulate and become preg on these cycles

• usually lower fertility due to damage to repro tract

Silent or Quiet Estrus/ Quiet ovulation

• during estrus, ovulation occurs but none of physiological signs of standing heat

• lack of receptors for estrogen in brain which form in response to having seen P4 from previous cycle

where would you see silent or quiet estrus

seen in farm animals on cycle before first standing heat or after long anestrus period

Will animals going through a silent or quiet estrus stand to be mated

no

Which of these are the cause of silent or quiet estrus

a) heat stress

b) stress

c) iodine limiting

d) predisposed condition

e) all of above

e) all of above

Anovulatory estrus

estrus w/o ovulation

• occurs in all farm animals

• ex: postpartum estrus in sows

What type of estrus is characterized as a continuous psychological desire to mate by female animal that’s not in heat

a) anovulatory

b) nymphomania

c) silent estrus

d) anestrus

b) nymphomania

T/F: ovulation rarely occurs in nymphomania

true

T/F: Nymphomania most occurs in cows (less in mares and rarely in sheep or pigs)

true

T/F: all individuals w/ cystic ovaries display nymphomania

false; not ALL

• cystic ovaries do USUALLY accompany nymphomaniac condition

T/F: during foal heat, mares have a high fertility rate

false

Anovulatory estrus can occur in what animals

a) only sheep

b) only dogs

c) English cows

d) all farm animals

d) all farm animals

spontaneous ovulation is the most common, hormonal, but does this require a male involved

no

What type of ovulation does this explain

• repeated ovulation at regular intervals except during preg

• LH release is cyclic and independent of mating stimulus

• LH release is triggered by increasing conc. of estrogen

---

a) spontaneous

b) mating induced

c) none of above

a) spontaneous

What animals does spontaneous ovulation occurs in

cow, ewe, sow, mare, rat, hamster, and guinea pig

T/F: in induced ovulation, ovulation occurs after stimulation of vagina and/or cervix, requires mating

true

In induced ovulations, LH release occurs only (before or after?) mating stimulus

after

How induced ovulation works

• lacks receptors for estrogen on cells that release LH

• nerve connection during mating

• nerves set off in vagina, which gives feedback to AP to trigger LH surge and ovulation

• absent of mating → follicles don’t ovulate

• mating is needed to trigger ovulation and CL

T/F: Continuous estrus animals (rabbits) are induced ovulators

• estrus persists for variable time

• occurs in rabbit, cat, mink, and llama

true

Long cycle animals: grow follicles → LH surge → ovulates → forms what

corpus hemorrhagicum and functional CL, corpus albicans

Small rodents have fast metabolisms have a physiological strategy that save energy normally assoc. with what phase of estrous cycle

diestrus

Non-preg cycle of rodent

growing follicles → ovulating → forming a corpus hemorrhagicum → not preg → SKIPS forming CL → returns to follicular phase

• how: systems require physical stim of vagina and nervous signal, which triggers CL formation and P4 production

• no signal, P4 lvls low → no negative feedback on hypothalamus and AP → animal goes right back to metestrus

Chart of Induced Ovulators, Short Cycle, and Long Cycle (KNOW)