Andrology
reproduction of male animals + humans
Gynecology
reproductive issues in woman
theriogenology
reproductive system of animals
obstetric
any intervention: females before, during and after partuition
Determination of sex in males
SRY protein - sex determining region gene - located on Y chromosome
Function of sertoli cells in fetus
produce anti-mullerian factor (AMF) - a hormone responsible for degenerate the mullerian ducts (primordial female reproductive tract) induce development of leydig cells
function of leydig-cells
produces testosterone partly converted into DHT by sertoli cells : Dihydrotestosterone is a hormone that stimulates the development of male characteristics
Determination of sex in females
No SRY or sertoli-cells so the mullerian ducts will not be degenerated since there is no testosterone produciton by the leydig-cells the wolffian ducts will degenerate ( primordial upper urogenital tract of males)
hormones produced by the ovaries
inhibin and progesteron
Layers of the female tract (outer–>inner)
serosa muscularis submucosa mucosa
What is the broad ligament and what is its parts?
continuation of the peritoneum, fiing the uterus contains essels, nerves and lymphatic drainage Mesovarium - around the ovaries mesosalpinx - around oviduct Mesometrium - around the uterus
What type of genital organ does the female - opossum - rabbit, mouse - pig - cow, ewe, doe - mare - human have?
- advanced duplex 2. duplex 3. bicornuate 4. bipartite 5. modified bipartite 6. simplex
How many layers separate the mother from the fetus
6 (3 from mother, 3 from fetus) endothelium connective tissue epithelial endothelium connective tissue epithelium
Placentomes of - cow - ewe - mare, sow
- convex 2. concave 3. diffuse
placentomes are buildt up of
chorion, caruncle and endometrium in cow and ewe chorion, microcotyledon and endometrium in mare and sow
what is special about the ovaries in the bitch?
the mesosalpinx comlpletely covers them - make it difficult for a complete spay. the ovarian bursa is making it difficult as well
receptors in antrum
estrogen inhibin FSH
receptors in theca interna
androgens LH
hormones produced by corpus luteum
P4 oxytocin relaxin inhibin activin
preovultory follicle - what degenerates?
The basement membrane - its is separating the theca interna and the granulosa cells - during ovulation and the oocyte and follicular fluid evacuates these cells start to mix - forming corpus luteum
Corpus hemorrhagicum
ruptured vessels during the ovulation forms a blood clot
cells of a functional corpus luteum
Large luteal cells - formerl granulosa cells small luteal cells - formerly thecal cells
what is different about cows and ewes ovarias when it comes to palpation?
the ovarian medulla and cortex are reversed so we can plapate the follicle but not the corpus luteum
structures found in 1. infundibulum 2. ampulla 3. isthmus
- fimbria 2. mucosal folds, caudally the ostium 3. uterotubal junction: regulates the movement of embryo into the uterus
structure of the uterus
mucosa + submucosa/endometrium muscularis/myometrium serosa/perimetrium
were does the uterine glands develop?
they develop from the endometrial mucosa and penetrates into the submucosa where they become coiled
functions of the uterus
sperm transport luteolysis + control of cyclicity environment for preattachmnt embryo feeding the embryo + spermataxoa maternal contribuation to the placenta expulsion of fetus + fetal placenta
What does the cervix provide?
a flushing system: mucosa production, lub + protecc a barrier: control sperm transport, isolation, protection, cervical seal during pregnancy
who has - cervical rings - cervical folds
- cow + ewe + sow - mare
What happens to the cranial/caudl agina when there is a high level of estrogen?
thickening - mechanical protection - prevents microorganim immigration
Species specific sperm deposition
Ru + Ca: intravaginal Su: intracervical Eq: intrauterine
What is the main hormone of the corpus luteum after ovulation? And what was it before?
main hormone after ovulation: progesterone Main hormone before ovulation: estrogen
GnRH pattern from the surge center
sensitive to positive feedback and will secrete in high amplitude high frequency pulses of GnRH in a short period after estradiol reaches a threshold concentration
Why does females have surge center and not males?
in females the oestradiol produced by the fetus ovaries are bound to alpha-fetoprotein hormone - making it impossible to pass BBB Testosterone in males goes through BBB converts to oestradiol and “defeminize” the hypothalamus, depressing the surge center, elaving only a tonic center
tonic center GnRH pattern
secretes small episodes of GNRH in a pulsatile fashion - episodi secretion is continous throughout reproductive life
Explain the hypothalamo-pituitary portal system
nerve endings terminating in the primary portal plexus - a network og blood vessels that will connect the hypothalamus with the anterior lobe (medial hypophyseal artery) transporting releasing hormones and connecting the anterior lobe (secondary portal plexus) - blood and releasing hormones
difference between the connection of the hypothalamus and the anterior/posterior lobe
anterior lobe: portal system only posterior lobe: no portal system, also known as neurohypophysis
Explain the transmission of communication from the paraventricular nucleus to the neurohypophysis
PVN produces hormones (regulating) axons stretch down into the neurohypophysis (PL) and is released into the capillary plexus within the PL
Result of a female having a surge center
preovulatory GnRH –> LH peaks
Overview of Kisspeptin
neuropeptides secreted by hypothalamus neurons to stimulate GnRH secretion
Task of kisspeptin
colelcts information both externally and internally - they will relay the information if the female is ready to reproduce, also the onset of the puberty
factors kisspeptin takes into its consideration
- leptin amount: too little leptin = no reproduction - blood fatty acid and glucose: needs to be positive for reproduction to start - seasonality: melatonin level
kisspeptin and its role in seasonality
different meaning to different types of breeders horse: long-day - low melatonin = increase GnRH sheep: short day - high melatonin = increase GnRH
GnRH level before and after puberty?
higher in female after puberty
Which follicles are FSH dependent?
emerging or recruited folicles, early selected follicles
Which follicles are LH dependent?
larger selected follicles, dominant follicles
Describe the effects of estradiol and inhibin on the hypothalamus and pituitary - early follicular phase vs later in the follicular phase
early follicular phase - GnRH pulse increase (low P4) - secretion of FSH + LH (AL) - stimulates follicles tor produce estradiol - giving a positive feedback –> more GnRH is produced - growth of dominant follicle and ovulation later - follicles will produce inhibin - inhibin has negative effect on FSH inhibiting the growth of other follicles
1st follicular wave
often 2 waves where the follicles are growing first one starts after metestrus (right after ovulation of the previous dominant follicle) no LH surge on the first wave - there is a high progesterone level with a functional corpus luteum so there wil not be any oulation this will cause the follicles to become atretic
2nd follicular wave
initiated around diestrus, it initiated before luteolysis, progesterone will drop, increase estrogen and surge will be initated supporting the follicular growth only follicles that are in a growing phase when luteolysis occur will become eligible for ovulation
Explain the “two cell-two gonadotropin” model of estrogen production of teritary follicles
Internal Theca cells will produce testosterone from cholesterol (LH receptors) testosterone is transported into granulosa cells (FSH receptors - FSH binds - enzymes of conversion is produced) the testosteron is converted into estradiol estradiol travels to the blood and causes estrous activity by affecting the brain and the reproductive tract
estradiol effect on brain - behaviural
lordosis (mating posture) increased phonation and physical activity
estradiol effect on reproductive tract
increased - blood flow - edema of tissue - secretion - leukocytes - smooth muscle activity - uterine gland growth
Explain induced ovulation
requires stimulation for there to be a GnRH release - coopulation or mating behaviour like licking nerve endings in the vagina will be stimulating causing the surge center to release preovulatory GnRH surge –> LH surge –> ovulation
animals having induced ovulation
Queens and rabbits
Explain luteolysis
PGF2a will bind to a receptor on the luteal cells - calcium influx - apoptotic - inhibits the conversion of cholesterol into progesterone leading to a physical regression and the cycle can start again
The effects of progesterone maintaining after ovulation
If progesterone is maintained (during pregnancy) it will have a negative feedback on GnRH - GnRH, LH and FSH is supressed - little secretion of estrogen positive effect on endometrium - endometrial glands increase secretion into uterine lumen - inhibits contraction of myometirum maternal recognition
What is silent ovulation?
ovulation after seasonal anestrus/puberty/gestation where there is no behavioural estrus
What is meant by progesterone priming the brain
after a silent ovulation, the progesterone produced by the corpus luteum will prepare it for the next estrus making it sensitive for estradiol so that there will be a full oestral behavior next time
Protein hormone mechanism of action
- hormone receptor binding 2. activation of adenylate cyclase 3. protein kinase activation 4. synthesis of new product
the 2 ways of mechanism of steroid hormone action
fast and slow response
Fast response of steroid hormones
- steroids binding to membrane receptors 2. activation of adenylate cyclase 3. protein kinase activation 4. synthesis of new product
slow response of steroid hormone action
- steroid transport 2. movement thorugh the cell membrane and cytoplasm 3. Binding of steroid to nuclear receptors 4. mRNA synthesis and protein synthesis
Example of fast responses of steroid hormone
estradiol: ion channel alteration, increase myometrial contraction progesterone: ion channel inhibition, decrease myometrial concentrations
example of slow responses of steroid hormone
estradiol: mucus secretion by female tract progesterone: uterine gland secretion
define cycle length and mention some in different species
interval from estrus to the next estrus most mammals: 20-21d sheep: 16-17d primates:28-37d
small cycle
estrous cycle
large cycle
from fertilization (pregnancy, partuition, lactation, resumption of cyclic ovarian function) to the next fertilization
length of anestrus, proestrus, estrus and diestrus in dogs when is the follicular phase and when is the luteal phase?
anestrus: 5month proestrus: 9d Estrus: 9d Diestrus: 3 month follicular phase: proestrus + estrus luteal phase: diestrus
Dominating hormone in follicular phase
estradiol - secreted by the ovaries stimulated by FSH and LH
Dominating hormone in luteal phase
progesterone secreted by corpus luteum + drop in progesterone after lutolyisis in strating
hormone causing the luteolysis
prostaglandin F2 alpa produced by the endometrium
The difference between estrous and menstrual cycle
Estrous: begins and ends with estrusand/or ovulation: long follicular phase Menses: ends with the start of menses, ovulation occurs in between two menses
How is cyclicity connected with daylight
production of melatonin by the pineal gland
how does melatonin affect short day breeders?
increased M will induce cyclicity
What is meant by circuannual species?
Deers, small Ru, some rodents have a bilogical clock, which induces cyyclicity around the same time of year
What is meant by non circuannual species
rats, mice continued photostimualtion can maintain cyclicity all year around regardless of the seasion
Why is light programs used?
to induce the cyclicity earlier in the year
Age of puberty in females - sheep, goat - swine - cattle - horse
7-10 4-7 8-11 15-18
What is the breeding weight and what is it in dairy cattle?
% mature weight at puberty the onset of the puberty is related to development - the animal can be of proper age, but in case the body is not in the correct developmental stage, puberty/estrus will not occur diary cattle: 30-40%
when does the endocrine reproductive system become functional?
end of the first trimester of fetal life
What happens to the function of ovaries/testies after birth?
First they become inactivated (several months) - The GnRH pulse generator in the arcuate nucleus is inhibited
is the reproductive system completely inactive after birth and prepuberal?
No, there is a subtle increase in gonadotropin pulses coming form the tonic center
Which hormone triggers the arcuate nucleus to resume the function of reproduction?
Leptin. it will rise trigger the ARC which will again trigger the GnRH pulse generator - now both the tonic and surge center is active and there will be the first ovulation
Which nucleus does the kisspeptin get information from?
anteroventral periventricular nucleus and arcuate nucles
What is meant by autoamplification processes after birth
when getting closer to the puberty and all other factors are in place the body will start to increase the production of all the pubertal hormones of the hypothalamus, pituitary and gonads
Primordial cell development in the ovaries
primordial cells migrate to the cortex of the gonadal ridge. Here the cells undergo mitotic division to increase their number prior tu puberty
Primordial cell development in the testes
Primordial germ cells migrate to the medulla of the gonadal ridge and become surrounded by mesenchymal cells to form primitive sex cords
explain - oocytogenesis - ootidogenesis - 2nd ootidogenesis
- undergoes mitosis forming the primary oocytes (2n) - undergo meiosis 1 forming secondary oocytes, the primary oocytes are halted in prophase 1 of meiosis until ovulation (2n) - secondary oocytes undergo meiosis 2, reminaing in metaphase 2 until fertilised (1n)
What is KNdy
the hormones kisspeptin, neurokinin B and dynorphin are released together
role of kisspeptin related to GnRH neurons
they act direclty on the GnRH neurons causing the release of LH and FSH which will again have a effect on testosterone and oestradiol - important in puberty
What modulates the activity of kisspeptin?
estrogen and progesterone, leptin, blood glucose, blood fatty acids
What is leptin
satiety hormone, made by adipose cells - inhibits hunger
What is ghrelin
hunger hormone
What is energy flux?
amount of energy consumed vs expended
Fate of follicles
grows to tertiary characteristic and degenerate
what is the number of oocytes ovulated for a cow?
17 cycles/year x 8 years = 136 oocytes ovulated/lifetime
How can we increase the number of ovualted follicles
can increase superovulation by fiving FSH to simulate the rescue of follicles which would have undergone atresia
where should the sperm be deposited in dogs?
vagina
where should the sperm be deposited in horse and cattle?
intrauterine
What are some ways to detect oestrus in horses?
- observation of behavioural and clinical signs 2. winking, motion of vulva, mucus 3. contact with stallion: standing reflex (teasing) 4. rectal palpation, ultrasound 5. progesterone test
Name the stage of cycle
without - di/metestrus
Name the stage of the cycle, can we inseminate?
reddening - early estrus
we cannot inseminate
Name the stage of the cycle
Can we inseminate?
reddeining + swelling
(check standing reflex)
estrus
YES, inseminate dat sow
When to inseminate the sow?
The vulva will redden and swell for 4 days, she will start honking and mounting. here you need to wait sometimes the reddening and sweeling disspaeras and then comes back, when it comes back. do the standing test
when she is standing this usually last between 2-5 days. inseminate first on 24h and then the second time on 36 hours
Estrus detection in cattle
- duration
- mounting activity
- standing duration
duration of estrus varies from 2-30h
70% of mounting happens at night
average duration of a stand by a cow in heat lasts only 4-6sec
Which hormones are responsible for the estrus behaviour?
it is controlled by E2 but previous P4 exposure is needed
Estrus detection aids (cattle)
presence of a bull
marker animals - chin ball
pressure sensitive mount detectors and tail paint
electronic pressure sensitive mount detector
electrical resistance of vaginal fluid
pedometry
What is a sidewinder?
A bull that has had a penile-prepuce transloaction
this allows normal protrusion and erection, but does not permit intromission
What is arborization or ferning?
high soduium chloride presence in the mucus during estrogen effect
crystallisation
List the major steps of oogenesis
- mitotic division of primordial germ cells (prenatal)
- nuclear arrest
- cytoplasmic growth (induced by LH surge)
- resumption of meiosis
In what stage is the ovulated oocyte?
secondary oocyte
How does the secondary oocyte become haploid?
The polar body gets extruded and is containing half of the genetic material
What is the granulosa cells responsible for?
Maturation of the oocyte
What is the journey of the spermatozoa after AI/mating? (to the oocyte)
it traverses the cervix, gets to the uterus. The ones that survive retrogade loss and phagocytosis/selection travels to the oviduct and enters it
here capacitation happens, hyperactive motility and phagocytosis happens before they can bind to the oocyte
Journey of spermatozoa after meeting the oocyte
goes through acrosome reaction
penetrates through the zona pellusida
formation of male and female pronuclei
fusion of the male and female pronuclei
cleavage divisions start (mitotic divisions)
hatching
Where is the capacitation initiated?
In the uterus, it is completed in the oviduct
Capacitation and the specifics of the sperm
- Epididymal spermatozoa: plasmamembrane covered in surface molecules (proteins and carbohydrates)
- Coating the epididymal sperm with seminal plasma: plasma protins masking the membran molecules
- Sperm exposed to female tract environment: seminal plasma molecules + some membrane molecules are removed
- binding to the zone pellucida is now possible
Zona binding: binding regions
ZP1 + ZP2: structural importance
ZP3: functional importance, gets in connection with the zona binding region of the sperm
What happens during acrosome reaction?
the plasma membrane overlying the acrosomal membrane begins to fuse with the outer acrosomal membrane, creating pores allowing the acrosomal enzymes to leave (hyaluronidase and acrosin)
These enzymes allows the sperm to penetrate though the zona pellucida
What happens just after the acrosomal reaction?
the fusion proteins are now uncovered, since the plasma membrane dissapears - they will take part in the connection of the plasma membrane of the oocyte and the head of the sperm
Explain the sperm-oocyte fusion
- after penetration of the zona pellucida, the spermatozoon reaches the perivitelline space
- the acrosomal membrane is still intact with the fusion proteins
- fusion proteins makes strong physical connection with the oocyte
- fusion allows the content of the cortical granules to be released into the perivetellini space by exocytosis
- this release i inducing the zona block, stpping other sperm cells to enter the oocyte
- the nucleus of the sperm is now in the cytoplasm of the oocyte where it start to decondense and the sperm nuclear membrane dissapears
List the sequence of events after capacitation
hyperactive motility
binding to ZP
acrosoe reaction
penetration of ZP
sperm-oocyte membrane fusion
sperm engulfed
decondensation of sperm nucleus
formation of male pronucleus
Developmental events after fertilization and before the embryo attachment
Blastomeres (small cells) start to divide mitotically until the 32nd cell stage - reaching the morula stage
further divison until the blastomere stage
Hatching
Explain the formation of blastocyst from the morula stage until hatching
In the outer cells of the morula there is a strong connection
in the inner cells of the morula there is loose connection
the outer cells will start to pump sodium into the inner part and this leads to an increasing osmotic pressure, water will flow into the cell creating a cavity.
- early blastocyst (small cavity)
- Blastocyst
- Expanded blastocyst
Explain hatching
Growth and fluid accumulation - increasing pressure
Production of enzymes by the trophoblastic cells
contraction of the blastocyst
ruptures away from the zona pellucida
cells of the blastocyst becomes uncovered and becomes able to implant in the endometrium
Trophoblast cells
develops from the the outer cells, attaching to the zona pellusida fromt he outside
flattened cells
placenta will develop from them
Which cells will the placenta develop from?
Trophoblast cells
Embryoblast cells
Developing from the inner cells
Foetus develops from these
Hormone important for maternal recognition
Progesterone - luteolysis must be inhibited
What happens when corpus luteum produces oxytocin?
stimualtes PGF2alpha production by endometrium
t
What does the PGF2alpha production depend on?
It depends on the threshold number of oxytocin receptors produced by the endometrium
What are the requirements for luteolysis?
presence of oxytocin receptors in endometrial cells
presence of a critiacal level of oxytocin
PGF2 alpha synthesis by th eendometrium
Maternal recognition
must occur before luteolysis
no endometrial oxytoxin receptor synthesis
no PGF2alpha production
MAternal recognition of pregnancy in ewe and cow
the blastocysts secretes IFN-t that blocks the synthesis of uterine oxytocin receptors
Maternal recognition in the sow
estradiol reroutes PGF2 alpha secreted by the endometrium
Maternal recognition of pregnancy of horses
the equine conceptus must migrate over the endometrial surface to initiate and complete maternal recognition of pregnancy + 3 protein and estrogens production