Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Therio Exam 2 > Reproductive Cycles and Ovarian Function > Flashcards

Reproductive Cycles and Ovarian Function Flashcards

1
Q

behavioral repro cycles

A
  • proestrus: starting to show a little bit of being in heat. not used in horses
  • estrus (standing heat = female stands to be mated)
  • metestrus: going out of heat and starting to develop CL = going out of heat
  • diestrus: out of heat
  • anestrus: lack of estrus: seasonal animals dormant; or period between dog cycles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

physiological repro cycles

A
  1. follicular phase
  2. luteal phase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how long is the cow estrus cycle?

A

21 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

**growing follicles make

A

estrogen!! with rise in estrogen and lack of progesterone, cow will start to be interested in showing heat = proestrus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how long is a cow in heat (estrus?)

A

12-18 hours, then ovulates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what hormone keeps the animal ou tof heat?

A

progesterone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

luteal phase is the physiologic phase that overlaps what biological repro phase?

A

diestrus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

when a cow is in estrus, what triggers the pituitary to start releasing LH?

A

rise in estrogen and absence of progesterone
LH causes follicles to mature and ovulate: stimulated by follicular production of estradiol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

if you have an animal with a CL and you give prostaglandin, what will happen

A

luteolysis: will destroy CL, gives animal a chance to come back in heat = short cycling the diestrus period to bring her back into heat early

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

after ovulation, how long do you have to wait in a cow or horse before the corpus luteum is mature to be able to give prostaglandin to cause luteolysis?

A

5 days: takes 5 days for CL to be mature to be able to respond to prostaglandins!!

only time PGE work to destroy CL is during the luteal phase but not until 5 days post-ovulation! does nothing when cow is in heat or anestrus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

primordial follicle

A
  • youngest/smallest version of follicle: thousands of them in the outer area of ovary
  • egg/oocyte in the middle
  • granulosa cells FLAT (follicular cells)
  • basement membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

**what is the hallmark of a primordial follicle?

A

single layer of cells, and the cells are flat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

primary follicle development

A
  • larger oocyte
  • zona pellucida formed around oocyte
  • CUBOIDAL GRANULOSA CELLS!!***
    single layer of granulosa cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the difference between a primordial and primary follicle?

A

primordial: FLAT cells surrounding oocyte + basement membrane
primary: CUBOIDAL granulosa cells single layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

hallmark of a secondary follicle?

A

MULTIPLE LAYERS of cuboidal granulosa cells surrounding oocyte
- granulosa cells surround oocyte in the basement membrane
- thecal cells are outside basement membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

tertiary follicle development

A
  • FSH and LH receptors develop
  • FSH stimulates initial follicular development
  • fluid filled ANTRUM forms within granulosa cell layer
  • follicular fluid produced by the granulosa cells
    multiple follicles coming up at the same time competing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is an antrum follicle?

A

tertiary follicle: fluid filled on inside from the secretion of the granulosa cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

hallmark of tertiary follicle

A

antrum: contains follicular fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

preovulatory follicle

A
  • granulosa cells secrete estrogens
  • LH receptors form on granulosa cells
  • LH surge occurs in response to increased estradiol production + increased GnRH pulse frequency
  • the LH surge causes the wall of the follicle to thin and rupture, allowing the egg to be released
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

ovulation

A
  1. LH surge: stimulates production of relaxin and prostaglandins from granulosa cells
  2. connective tissues in follicular wall disrupted
  3. rupture of follicle occurs
  4. oocyte released and “caught” by oviduct
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how is the corpus luteum made?

A
  1. follicular wall gets bigger and bigger from LH surge
  2. follicle collapses and fluid evacuates = ovulation
  3. fills back up with blood = corpus hemorrhagicum
  4. fibrin strands invade, cells come in = surround and fill in structure
  5. now have the corpus luteum = “yellow body” = makes progesterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

T/F: the ovary and the oviduct are connected

A

FALSE: the ovary is independent of the oviduct: oviduct catches the egg to keep it from being released into the abdominal cavity (ectopic pregnancy)

23
Q

induced ovulation

A
  • cats/llamas/ferrets/camelids
  • mating triggers ovulation by neurological pulse up spinal cord to hypothalamus: release of LH from anterior pituitary
  • follicular development stimulated by FSH
  • coitus induces LH surge
  • ovulation-inducing factor in semen
24
Q

what factor do camelids have to help stimulate ovulation? (llamas/camels/alpacas)

A

nerve growth factor- B: ovulation inducing factor in semen! triggers output of LH from pituitary

25
T/F: cats and camelids rely on nerve growth factor B for ovulation
false, just camelids, cats don't rely on it
26
in the absence of mating in induced ovulators, the cycle consists of only what phase
follicular phase: no luteal phase mating stimulates LH surge and ovulation
27
corpus luteum
- after ovulation, CL forms in place of where follicle was - function: secretion in progesterone - not mature until day 5 after ovulation - progesterone required for maintenance of pregnancy
28
how is the CL formed?
- after ovulation lumen of collapsed follicle fills with blood = corpus hemorrhagicum (CH) - blood clots, fibrin strands develop within clot - granulosa and thecal cells invade CH along fibrin strands - luteinization of cells occurs
29
what is the structure responsible for taking animals out of heat and keeping them in pregnancy?***
corpus luteum: makes progesterone!!!
30
what is the corpus albican?
the structure formed after the corpus luteum = it dies and becomes the white body and basically scars over
31
after ovulation, when do progesterone levels begin to increase?
1-2 days after ovulation dogs exception: their progesterone levels rise prior to ovulation
32
in the dog, when do progesterone levels begin to rise?
PRIOR to ovulation! different than all other species
33
in the dog, what is the trigger for estrus/standing heat?***
rise in progesterone!! the LH surge causes a rise in progesterone, which triggers standing heat/estrus. don't go into heat until progesterone is high!! - this does not happen in any large animals: a rise in progesterone causes them to go OUT of heat!!
34
what is the hormone that maintains/supports the CL?***
LH: most important luteotropic hormone: keeps it active and alive and making progesterone - CL function is maintained by pulsatile LH release
35
how does transfer of PGF2a from uterus to ovary occur?**
1. local counter-current system: ruminants 2. general systemic circulation: horses/pigs
35
how do non-pregnant females initiate another reproductive cycle?
they have to regress their corpus luteum! have corpus luteum for 14-18 days - if not pregnant, uterus endometrium releases prostaglandins: will destroy CL and then LA can come back into heat
36
what is the natural prostaglandin?
- PGF: prostaglandin F2a - produced by endometrium of uterus - causes CL to regress in LA - no role in CL regression in cats/dogs/primates why it is very important that the embryo tells the uterus that it is there!
37
what animals use a local counter-current pathway to transfer prostaglandins from the uterus to the ovary?***
ruminants: sheep/cow/goats
38
what animals use a general systemic circulation to transfer prostaglandins from the uterus to ovary?**
horses and pigs
39
how does the prostaglandin transfer work in sheep/cattle?
- local counter-current pathway - prostaglandins secreted into the vascular bed from the endometrium/uterine lining - the vein leaving the uterus is heading in the opposite direction as the artery because the artery is heading towards the OVARY! - get a prostaglandin hormone exchange: the artery wraps around the vein, and PGE is able to cross membranes - get transfer of PGE from vein to artery: reaches ovary and if there is a CL there, it will destroy the CL
40
what is really important to remember when doing an embryo transfer (think which side)***
when doing an embryo transfer, the CL has to be present on the SAME SIDE that the pregnancy is established this is because the embryo/pregnancy will tell the endometrium to not release prostaglandins: those will destroy the CLand the embryo will fade away - transfer embryo into heifer on the SAME SIDE as her corpus luteum so pregnancy tells endometrium to not release prostaglandins
41
how does the horse/pig transfer of PGE from uterus to ovary work?
- horses and pigs also make prostaglandins in the uterine lining, but it leaves via the uterine vein and goes into GENERAL CIRCULATION - does not have counter current circulation - travels thru whole body: half life is very short and is rapidly metabolized in the lung - give big boluses to get into systemic circulation, and will go to the ovaries and the side that has the CL will be destroyed
42
T/F: PGF2a is released in a pulsatile pattern
TRUE!
42
Corpus luteum regression
destruction of CL results in non-functional corpus albicans (CA) does not produce progesterone
43
luteal regression in dogs and cats
- do not utilize PGF2a for early regression of the CL after a non-conceptive cycle - luteal phase of non-preggo dogs/cats is 70 and 35 days - progesterone production slowly decreases and then stops
44
why can you not use progesterone to tell you whether an animal is pregnant or not?
ex in the dog: from a CL in a dog that is pregnant or not pregnant, the amount of progesterone is indistinguishable in the 2. this is why you cannot use progesterone to say whether they are pregnant or not pregnant
45
when a dog whelps, is the progesterone higher or lower?
progesterone drops rapidly
46
luteolysis in the llama
- induced ovulator: only has progesterone around if mated - day 12: maternal recognition of pregnancy - if not pregnant, PGE released and CL destroyed - if pregnant: progesterone increases, and at day 12 PGE withheld: signal to uterus to withhold PGE - can take a blood sample after 20 days of mating, and if levels are high, likely is pregnant because they are induced ovulators
47
how can you prolong the life of a CL?***
1. pregnancy 2. pregnancy loss after maternal recognition of pregnancy 3. chronic uterine infection*** 4. indequate PGF2a
48
what is the equivalent of a pyometra in large animals?***
chronic uterine infection = chronic, big fluid accumulation, often have enough damage to uterus that they will not produce prostaglandins and they will have a retained corpus luteum!
49
what can cause premature luteolysis?**
1. PGF2a administration: exogenous treatment 2. endometritis: acute inflammation of the uterus causes premature PGF2a release (endogenous)
50
you are called out to a farm because the producer has noticed one of his cows has come into heat early, around day 7, when she wasn't due to come in until day 18. you ask him if he administered any prostaglandins and he says no. what diagnostic tests do you immediately do?**
diagnostic tests for infection of the uterus! any cow or horse that short cycles without being administered anything is immediately suspect of having bacterial endometritis: inflammatory condition causing PGE release from the cells in the uterus. likely need abx
51
cows and horses that are short cycled naturally are ***
INFECTED

Therio Exam 2 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions