Endocrinology Flashcards
(108 cards)
1
Q
In female endocrinology, what are the three groups??
A
Gonadotropins
Sex steroids/prostaglandins.
Mammotropins
2
Q
What do gonadotropins do?
A
Stimulate ovary to produce
3
Q
What do sex steroids/ prostaglandis do?
A
Direct control of the reproductive state
4
Q
What do mammotropins do?
A
Involved in lactation.
5
Q
What is extremely impoarnt in animal management?
A
Lactation!
6
Q
What are the two gonadotropins?
A
Luteinizing Hormone (LH)
Follicle stimulating hormone (FSH)
7
Q
What does the Luteinizing hormone (LH) gonadotropin do?
A
-Causes ovulation
-Stimulates final growth of follicles
-Also stimulates corpus Luteum.
8
Q
LH is involved in what?
A
The last stage of follicle development and the last stage of ovulation. Think L equals last.
9
Q
What does the Follicle stimulating hormone (FSH) Gonadtropin do?
A
-Stimulates all stages of follicle growth, especially early periods!
10
Q
Where is FSH produced by?
A
The pituitary gland.
11
Q
FSH is involved in which state of most things?
A
The first stage of most things
Think F = first
L = last.
12
Q
What are the three sex steroids/prostaglandins?
A
Progesterone
Estrogen
Prostaglandin
13
Q
What does progesterone do?
A
Responsible for maintenance of pregnancy
Also prepares to get pregnant.
Inhibits gonadotropin secretion.
14
Q
Where is progesterone produced?
A
In most animals, the Corpus Luteum!
In some, the placenta (Horse)
15
Q
What is the overarching purpose of progesterone? Why?
A
Prepare and maintain pregnancy.
It reduces LH and FSH and quiets the system!! You dont want follicles to develop when she is pregnant!!
16
Q
Of the sex steroids, what does estrogen do?
A
-Prepares the reproductive tract to be bred.
-generally responsible for the estrus cycle
-Responsible for female mating behavior
-Prepares female for breeding and parturition.
-Stimulates pre-ovulatory surge of gonadotropins.
17
Q
When and where is estrogen produced?
A
Produced by growing follicles, placenta, and embryos.
-Right before giving birth, estrogen start to be produced by the placenta.
18
Q
What is the effect of estrogen on gonadotropins?
A
-It has both a positive and negative effect on gonadotropins
-We would say overall effect on gonadotropins is positive.
19
Q
When estrogen is high, what happens?
A
LH and FSH is high!
20
Q
Of the sex steroids/prostaglandis, what is Prostaglandin?
A
-Primarily produced by the uterus.
-Responsible for luteal regression
-Destroys the CL.
-Causes uterine contractions at birth.
21
Q
What are the two mammotropins?
A
Prolactin
Oxytocin
22
Q
Describe what Prolactin is.
A
Produced in the pituitary gland.
Stimulates production of milk
23
Q
How does prolactin contribute to lactation?
A
It stimulates production, but has NOTHING to do with milk release.
24
Q
Describe Oxytocin.
A
-Produced by uterus and hypothalamus
-Stimulates milk excretion
-Stimulates Uterine contractions.
25
Why might oxytocin stimulate uterine contractions??
You want milk to be available immediately when the baby is born.
26
What is Parturition?
Birth!
27
Give a rundown of the female cycle.
Puberty, into the estrous cycle, into gestation, into birth, lactation, weaning, into either the estrous cycle again or rebreeding.
28
Why is the cycle a little bit different for each animal?
In some, the female is rebred before the baby is weaned. Some are right after, some are given a couple of cycles before they are rebred.
29
WHat is the period after birth often called?
Post-Partum period.
30
Describe what a reproductive cycle entails.
Invovles interactions between the ovary, uterus, mammary gland, and brain.
these organs communicate using hormones and nerves.
31
Define Puberty
The age at which an animal is capable of adult reproductive function.
32
What does puberty look like in males?
Libido, mating, and production of fertile sperm.
33
What does puberty look like in females?
Estrus, production of fertile eggs, maintenance of pregnancy.
34
Generally, what is the last function to muture during puberty?
The brain and the production of gonadotropins.
Specifically LH!
35
What is the least understood part of the cycle of reproduction?
Puberty!
36
What is first capable of reproducing?
Gonads before the brain!!
37
WHat is a gonad?
In females the ovaries.
In males the testicles.
38
What is the biggest limiting factor for puberty to start? Why?
Luteinizing Hormone (LH)
The brain takes longer to develop and produce LH than the gonads take to produce their hormones.
39
What is the estrous cycle?
Repeatable sequence of events that results in female becoming sexually receptive.
40
What is the point of the estrous cycle? Explain.
For the female to get pregnant. If she doesnt, it will repeat until she does.
41
What is estrus?
Period of sexual receptivity.
42
Explain what happens hormonally during estrus.
Estrogen is high and progesterone is low.
High estrogen causes preovulatory surge of gonadotripins.
43
Explain ovulation.
LH surge causes ovulation.
The follicles release eggs
The estrogen decreases
CL (Porpora lutea) form.
The CL produces progesterone.
44
What is the hormone cycle from the start of estrus to ovulation?
Start with high estrogen, then as you ovulate you go to low estrogen and high progesterone to prepare for a preganacy.
45
During day one of estrous, what do hormones look like?
High estrogen, low progesterone.
LH and FSH are very high because progesterone is not supressing them
46
On days 1 through 5 of estrous, what is happening hormonally?
Estrogen is sharply decreasing. Progesterone is slowly increasing.
LH and FSH are very low due to progesterone suppressing them.
47
What happens hormonally between day 6-13ish of the estrous cycle?
Progesterone platues and stays very high. Estrogen stays very low.
LH and FSH stay very low.
48
What is different about days 12-14 of the estrous cycle?
Prostglandin spikes super high and then drops dramatically.
49
WHat happens after day 13-20 in estrous cycle?
Progesterone starts to drop.
Estrogen starts to rise
In turn, LH and FSH will start to rise too.
50
In the above cycle details, what is this representing?
The estrous cycle of a female that did not get bred.
51
How long is the CL and progesterone maintained?
From about 12-16 days
52
Why does the prostaglandia spike like that?
Spikes around day 14 from the nonpregnant Uterus.
This destroys the CL.
53
If the female doesnt get bred in the _______ days, the ____ gets _____ and _____ goes down.
12-16 days. CL gets destroyed. Progesterone goes down.
54
After the CL gets destroyed, what happens? what days?
After about 16 days. Progesterone goes down, Gonadotropin does back up, estrogen goes back up, follicles start to regrow, cycle restarts.
55
How long are estrus cycles genreally?
About 21 days.
56
What actually causes progesterone to go down after about 15 days??
The prostaglandin from the uterus that isn't pregnant. Destroys CL, progesterone starts to fall. Estrogen increases. Cycle restarts.
57
If progesterone doesnt drop back down during the females cycle around 15 days, what does it mean??
Shes pregnant!
58
If you dont breed your animal and take hormon levels at day 21 and the progesterone is high, what does it mean?
The animal is pregnant! She snuck out or something.
OR prostaglandins are not working!! The uterus did not give the signal to destroy the CL.
59
What hormon is high at the beginning and the end of a nonpregnant cycle?
Estrogen and gonadtropins like LH and FSH.
60
Pregnancy. Define it.
Occurs after ovulation if there is a successful breeding.
Fertilization occurs and embryonic development occurs.
61
Before an embryo splits past 8 cells, what is special about each cell? What is this called?
Any cell that is removed can develop into a complete animal!
Called totipotent.
62
When does the females body recognize that she is pregnant. How does it know?
Around 12 days after fertilization.
The embryo sends a signal to the mother.
63
How does a pig embryo send the signal?
A ruminant?
A horse?
Pig embroys use estrogen
Ruminates use proteins
We dont know what horses use! (of course)
64
When does the embryo start differentiating?
Around day 12! The cells are no longer totipotent.
65
What is happening hormonally after the female is imprenanted.
Prostaglandins are not released from the uterus and because of that, progesterone is maintained.
Estrogen does NOT start to rise and the progesteron keeps the gonadotropins repressed to protect pregnancy.
66
Describe a estrus hormone cycle where the female gets pregnant.
We start with very high estrogen. LH and FSH (the gonadotrophins) are very high. Then, like normal, the estrogen drops sharply, Progesterone starts to rise.
LH and FSH drop sharply as well.
The female is fertilized and the progesterone maintains.
67
What is the Blastocyst?
Early embryo. When cells start to split.
68
Of the blastocyst, what is the inner cell mass? What will it become?
The inner cell mass, different cells will become different things!
Could be a lung or a muscular system.
Around 12 days, basically when the cells start to differentiate.
Becomes the fetus.
69
Of the blastocyst, what is the outlining called? What will it become?
The trophoblast. It will become the placenta.
70
Of the blastocyst, what is all of the space between the inner cell mass and the trophoblast called?
Blastoceole.
71
When does an embryo become a fetus?
When it begins to differetiate and begins to take the shape and form of a young animal.
72
What are fetuses doing?
Still differentiating. But increasing in size very rapidly.
73
People often use fetus and embryo.... Why is this wrong?
Interchangeably! It only becomes a fetues when you can start distinguishing features.
74
What is a pattern of all animals with internal reproductive systems?
The fetus develops its frame and doesn't start to add weight until the very end of gestation.
The last third of pregnancy or so.
75
If females are having late births, and are having runts with a lower chance of survival, where do you need to look?? Or if you have a herd with low birth weights.
You need to look at the last third of gestation!
76
In fetal growth, describe the pattern between weight and length!
Length increases steadily, weight stays low and then starts to increase sharply in the last third.
77
Who initiatess parturition?
The fetus!
78
Hormonally, what happens at parturition?
Prostaglandins are released and progesterone decreases.
After this, endocrine changes vary among species.
79
What is unique about horses? (Of course)
When birthing, first the progesterone spikes and then decreases like normal
80
What hormon do we believe the fetuses release when its time to birth? What is the imporance of this?
Cortizal! This must happen if the birth is going to be successful and smooth.
81
What is the Fergusons relfex?
A neural reflex arc.
82
Describe the Fergunsons reflex.
There are pressure recptors in the cervix that are connected to the pituitary gland in the brain through nerves.
The fetus pushes on these nerves, the nerves send the signal to the brain and the pituitary gland, then oxyocin production begins.
The oxytocin stimulates contractions to push the fetus through the birth canal.
83
When does the ferguson's reflex happen?
At the beginning of parturition.
84
Why is lactation such an important part of reproduction?
Everything can go completely perfectly, but if the female can not feed the young, it doesnt matter. the baby will die.
85
What is lactation?
Another neural reflex arc!
86
How does lactation work?
Physical stimulation of the nipple during nursing causes prolactin and oxytocin release.
Nerves run directly from teets to the brain.
87
Describe what is happening during nursing hormonally.
Baby, suckles, triggers the reflex arc.
Prolactin produces the milk for the next meal.
Ocytocin causes milk to release for the current meal.
88
When a newborn nurses, what is it doing?
Stimulating production for its next meal and getting a current meal.
89
If a newborn can nurse, what will happen?
The neural reflex arc is not triggered. The hormons wouldnt produce and the mom will dry up.
90
What do we do if young cant nurse?
You get older and bigger pigs to nurse for a bit so the mom doesnt dry up.
Then, when the newborns are able to nurse you go back to normal.
91
In general, how do you go about rebreeding?
You remove young so that lactation stops. You ween young
When milk production stops, LH and FSH increase. the mothers body should start developing follicles again. Estrus starts again!
92
Why doesn't a female come into heat when a baby is nursing?
The suckling action prevents release of LH and FSH through another reflex arc.
93
Who is the exception to the rebreeding process?
The horse! (Duh)
They can have foal heats.
94
What is a foal heat?
The mare can go into heat at the same time as nursing young.
95
After birth and during lactation (Before weening) What do hormones look like??
Progesterone is low, estrogen is low, LH and FSH is low.
96
How you _____ an animal in the _____ phase affects the ___ stage.
Manage, previous, next.
97
How you manage an animal in the previous stage affects the next stage. Explain.
Ex: If you did not manage the animal properly during puberty, it is unlikely that estrus will go well.
98
Does the male endocrinology go in a cycle? Explain.
NO! They are constantly producing sperm and it is fairly continuous.
99
Why do the males constantly produce?
They need to be ready to breed at anytime. They dont know when they are going to meet a female that is ready to bred.
100
Explain hormones for males.
FSH and LH stimulate sperm production.
FSH and mostly LH stimulate testosterone production.
101
Where is mature sperm stored?
In the tail of the epididymis.
102
In a boar, how long does the entire process of the sperm cells leaving the resting pool until storage?
35 to 42 days.
103
Why can fertility issues be so difficult to figure out?
It could be an issue with the male, female, or both.
It is hard to figure out what part or stage is causing issues.
104
Describe breeding from the female perspective.
Ovum start in the ovary. Estrus and ovulation happen and egg travels to oviduct.
Sperm goes from the vagina, through the cervix, uterus, and meets in the oviduct.
Fertilization happens in the oviduct, fertilized egg travels to the uterus. There, embryonic and fetal growth occur.
Then, fetus travels through cervix and exists the vagina and vulva during parturition.
105
If there is an abortion, where is the problem? Think about where and when in the cycle.
Which parent is this issue coming from and why?
The issue in the Uterus.
Cant be the male, because the female already got pregnant.
106
What is it called when a cell is no longer totipotent?
Unipotent!
107
If someone accidentally gave LH to a pregnant cow what would happen?
There would be an increase in progesterone from the CL which should assist with or promote pregnancy. There
really wouldn’t be any follicular growth since LH works on large follicles and all the follicles would be small
during pregnancy. It isn’t really correct to say nothing would happen since you would get an increase in
progesterone, but pregnancy would still continue normally.
108
There are two neural reflex arcs active during the entire reproductive cycle in females. What does each one
of them do?
Both occur during lactation. One is associated with milk production and ejection (oxytocin and prolactin
release) and the other prevents the release of gonadotropins so females don’t exhibit estrus while young
animals are nursing.
