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DVM 2 - 2 > Repro 2 > Flashcards

Repro 2 Flashcards

1
Q

Ovary what type of epithelium and what is within the cortex and medulla

A

Simple squamous to low columnar to cuboidal epithelium
Cortex
- Has follicles of different stages as well as corpora lutea and corpora albicantia
- In carnivores and rodents cords of hormone producing endocrine cells are present possibly arising for theca interna of degenerated mature follicles
Medulla
- Loose connective tissue with smooth muscle that is continuous with mesovarium
- Less cellular than the cortex

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2
Q

establisment of follicles what are the phases and epithelium

A

1) oogonia - presumptive follicular cells
2) oocyte (meiosis of oogonia)
3) primordial follicle - primary oocyte surrounded by squamous follicular epithelium
2) Primary follicle - primary oocyte surrounded by simple cuboidal (later matures into columnar)
3) Secondary follicle - primary oocyte surrounded by stratified follicular epithelium of membrane granulosa cells, formation of the zona pellucida and differentiation of thecal layer, oocyte and follicle increase in size
4) Tertiary follicle

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3
Q

What are the 4 layers of the tertiary follicle

A

1) Cumulus oophorus: a multilayer of membrane granulosa cells surrounding the oocyte + the oocyte
2) Corona radiata: a layer of radially disposed columnar granulosa cells of the innermost portion of the membrane granulosa cells
3) Membrane granulosa cells: contains FSH receptors and in late tertiary follicles LH receptors
4) Endocrine cells of the theca interna: contain LH receptors and respond to LH stimulation by producing androgens into the membrane granulosa which are converted to oestrogens under influence of FSH
§ Oestrogens create a favourable local environment

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4
Q

Uterine tube what lined by and different layers

A
  • Lined by simple columnar or pseudostratified columnar epithelium with cilia and microvilli
    ○ Ciliated cells predominant the ampulla and decrease towards the isthmus
    ○ Provide propulsion for the ovum in the ampulla
  • Lamina propria/submucosa comprises of thin layer of loose connective tissue containing plasma, mast cells and eosinophils
    ○ Forms longitudinal folds that are well developed in the ampulla
  • Tunica muscularis consists of circular smooth muscle that varies between species
    ○ Larger amount in isthmus -> muscular movement of the ovum
  • Vascular tunica serosa is continuous with supporting mesosalpinx
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5
Q

What are the 3 layers of the uterus body and horns and what within

A

1) endometrium - mucosa/submucosa, glands - coiled or branched tubular glands which open into uterine lumen, caruncles (vascular endometrial thickenings form raised mounds on luminal surface)
2) myometrium - tunica muscularis, thicke inner and thin outer longitudinal layer
3) perimetrium - serosa, loose connective tissue layer covered by mesothelium and continuous with mesometrium

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6
Q

Cervix what rich in in terms of fibres and cells and what are the 3 layers consisting of

A
  • Thick wall muscular tube that is rich in elastic fibres
  • Simple columnar with mucigenic cell and goblet cells
    ○ Produce cervical mucus which contributes the bulk of the vaginal and vestibular mucus present
  • Mucosa and submucosa thrown into folds and consist of dense irregular connective tissue that becomes oedematous during oestrus
  • Tunica muscularis comprises an inner circular layer is modified to contribute to the interdigiting fold and prominences in small ruminants and the sow
  • Tunica serosa of loose connective tissue and a mesothelium surrounds the organ
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7
Q

What are the 3 layers of the vagina what what comprised of

A

1) Mucosa
- Lined by stratified squamous epithelium that increases in thickness at oestrus
- The presence of epithelium and sub-epithelium glands varies between species
2) Tunica muscularis
- Comprises of 2 or 3 layers of smooth muscle, thick inner circular layer and thin poorly defined outer longitudinal layer
○ Sow and carnivores have additional inner longitudinal layer
3) Tunica serosa
- Contains extensive vascular plexuses and is highly innervated

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8
Q

Vaginal Epithelium undergoes cyclic changes within the oestrous cycle what occurs in the cow and bitch

A

Cow
- under influence of progesterone the epithelium is 3-10 layers of cells thick there is an influx of lymphocytes
- Under influence of oestrogen the epithelium thickens by cellular proliferation, but true cornification does not occur
Bitch
- During anoestrus the vaginal epithelium is thin
- During proestrus the epithelium proliferates to 12-20 layers of cells, oestrus the epithelium cornifies
- Late oestrus there is desquamation

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9
Q

what are androgens and estrogens

A

Androgens -> male reproductive hormones
Estrogens -> female reproductive hormones
ANGROGENS CAN BE CONVERTED INTO ESTROGENS

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10
Q

What is HCG and LH and how used in pregnancy testings

A

HCG = human chorionic gonadotrophin
- Produced by the placenta in humans -> test for pregnancy
- Acts similarity to LH -> ovulation induction
LH
Ovulation test - could also be responding to HCG

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11
Q

What are the 2 main reasons there will be stallion behvaviour in a gelding

A

1) 1/3rd maintain the stallion behaviour after being gelded

2) Cryptorchid -> undescended testes -> not gelded properly

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12
Q

What are the 4 main tests to determine between stallion and gelding and characteristics of each

A

1)Testosterone
○ Not as reliable
2) Oestrone sulphate
○ 1 sample -> easier
○ Not reliable in horses under 3 and not a donkey
○ Produced by the testis -> high amount then must have testis tissue -> possible cryptorchid
3) LH response test -> dynamic test
○ Multiple samples -> later so sometimes not as practical
○ High accuracy 95%
4) AMH testings
○ More sensitive and specific then oestrone sulphate
○ New gold standard but not that expensive
○ Produced by sorteli cells

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13
Q

what occurs with male from hypothalamus to oestrogens production

A

Hypothalamus
-> GnRH
Anterior pituitary
-> LH and FHS
Testis
-> LH acts on Leydig cells to produce testosterone -> bind Androgen binding protein (ABP) in the blood
-> FSH stimulates Sertoli cells that produce ABP and AMH -> ABP grab the testosterone and the Sertoli cells convert it to oestrogen

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14
Q

list 3 reasons for only having one testis and what is bad

A

1) Cryptorchid
- Undescended testis -> stays within the abdomen
- There are some inheritance involved -> multiple genes involved
○ Issues if breeding the animal - not reproductively sound
BAD -> can become neoplastic or necrosis within the abdomen due to decrease temperature regulation (possibly)
2) Trauma -> if really damaged just remove
3) Tumour -> removal of testis

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15
Q

What is anoestrus and the two types

A
  1. Condition in a female when she does not display oestrus
  2. An interval of sexual inactivity between two periods of oestrus in female mammals that breed cyclically
    True anoestrus -> caused by insufficient hormonal stimuli
    Apparent anoestrus -> failure to detect oestrus
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16
Q

List 6 things that causes anoestrus

A
  • Lactation
    • Season
    • Presence of offspring
    • Stress
    • Pathology
    • (Pregnancy)
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17
Q

What are the 4 different types of anoestrus and the species involved with

A
  1. Polyoestrous -> cattle, queen, pig, rodents
  2. Seasonal polyoestrous “long day” -> mare -> cycle in summer, anoestrus in winter
  3. Seasonal polyoestrous “short day” -> small ruminants -> cycle in winter, anoestrus in summer
  4. Monoestrus -> dog, bear, fox independent of the season, long periods of anoestrus between oestrus
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18
Q

What is organ is important for seasonal breeders and what is the difference between short and long day breeders

A

Light is important
- therefore the eye is very important -> registers the light -> sends to pineal gland (melatonin produced at night)
○ Mare will take a year to cycle again after goes blind -> not sure how starts to cycle again
- Long day breeders -> kiss neurons are stimulated by low melatonin -> increase GnRH -> increase FSH and LH -> cycle
- Short day breeders -> kiss neurons are inhibited by low melatonin -> decrease GnRH -> decrease FSH and LH -> DON’T CYCLE

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19
Q

Canine oestrus cycle what is the landmark of the beginning of oestrus and how often does it go into oestrus

A
  • LH peak is the landmark!!!!! -> end of follicular phase just before ovulation (36-48 hours later)
    ○ Marks the beginning of oestrus
  • Only has oestrus every 7 months
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20
Q

Prooestrus in dogs, duration, what occurs and the oestrogen and progesterone levels

A
  • Average duration of 9 days
  • This is when bleeding occurs -> not shedding internal lining but due to hyperaemia
  • Maximum oestrogen levels - different from others
  • Progesterone is starting to rise
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21
Q

Oestrus in dogs what occurs in terms of hormone levels and what to test for to determine whether occurred

A
  • Starts the with LH peak (only lasts 12-24 hours so can miss this rise -> therefore test progesterone)
  • Also getting increase in progesterone that continues to rise then stays up -> what looking for to detect the LH surge
  • Remains elevated for a long time which suggests there isn’t a mechanism for luteolysis
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22
Q

What is the difference in progesterone levels between pregnant and non-pregnant dogs

A

Progesterone levels are similar in pregnant vs non-pregnant
Sudden decrease 65 days after ovulation in pregnant animals due to patriation -> removal of progesterone
THEREFORE CANNOT USE PROGESTERONE TO TEST WHETHER ANIMAL IS PREGNANT OR NOT

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23
Q

Doestrus in a dog how long

A
  • Average of 57 days in pregnant and slightly longer in non-pregnant bitch
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24
Q

What is a typical timeline from oestrus to fertilisation in dogs

A

LH surge = day 0 -> first day of oestrus
2-3 days later ovulation occurring -> 1 day to ovulate everything
Another 2-3 days to mature the oocytes
ONLY THEN CAN BE FERTILISED, can be fertilised for 2-3 days
- Lots of notice to breed the dog -> not a rush

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25
Q

What are the 2 induced ovulator species and how are each induced

A
  • Alpaca (Camelids) and cats
  • Something must occur to ovulation
    ○ Cats -> multiple copulations -> physical act
    ○ Camelids -> copulation -> factor in the semen therefore can artificial inseminate and will result in ovulation (not in cats)
    ○ Are exceptions to the rule some oriental breeds can spontaneously ovulate
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26
Q

Cats what occurs if they are and aren’t mated

A

○ If not mated within the heat of the week will go into post-oestrus for a week (not on heat), oestrogen and progesterone levels are low
§ Then New follicular wave will occur increase oestrogen and then will go through week of heat, if not mated repeat cycle
○ If mated then will get LH surge and increase in progesterone and ovulation
§ If mated and ovulate and do fall pregnant will stay on heat until parturition
§ If mated and ovulate and don’t fall pregnant can have pseudo-pregnancy so progesterone levels remain high but not as long as they do in dogs

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27
Q

What are the main behaviours from cows in prooestrus and in oestrus and problem with detecting these

A
  • Prooestrus will start mounting, Restlessness -> odometers, Vocalisation
  • Oestrus -> cow will be mounted, presence of ruffled hair at base of the tail, rubbed of tail paint
    Problem
  • 70% of cows will show heat between 6pm and 6am when handlers aren’t present
  • Therefore use tail paint, heat detection devices (kamar)
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28
Q

What is important in teasing the mare

A
  • Teasing records very important to veterinarian
  • Preferably done by same person every day
  • Mares must be teased regularly (ideally daily) from 3 days post-partum until 60 day pregnant
  • Teasing chute/wall is ideal (open front and back)
  • Mares have individual teasing patterns
  • Generally use ponies -> horses generally don’t like grey ponies
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29
Q

What is important in the layout when teasing the mare and 3 behaviours of mares on heat

A

Layout
- Mare needs to have room to kick and not hurt herself
- Stallion starts at head and is then allowed to move backwards and ideally rest head on croup
Behaviour
- Urination
- Winking
- Standing to be mounted

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30
Q

What are 4 main ways canine oestrus detection in performed

A
  • “Breeding reflexes” - behaviour of the dog
  • vaginal exam- speculum -> look within the vagina looking at the fold, oestrogen high round folds and pink, very wrinkly
  • exfoliative cytology - keratinised dead cells
  • serum progesterone levels - to determine LH surge
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31
Q

Describe the 2 basic mechanisms for manipulation of the oestrus cycle in cows

A
  1. Inducing luteolysis - luteal phase is shorter -> prostaglandin F2alpha
    ○ All animals will be refractory (not respond) to effects after the first 5 days after ovulation
    ○ Day 6-17 days of the cycle will shorten the luteal phase, decrease the time to get the animal in heat
  2. Prolonging luteal phase - progesterone device placed into uterus
    ○ Rapid uptake of progesterone
    ○ Stays elevated and keep in 7-12 days before removed
    § Within a few hours after removal progesterone will go down again
    § When remove give a shot of prostaglandin just in case has a corpus luteum so the progesterone levels decrease
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32
Q

What is involved in the presynch cycle in cows

A
  1. If give to herd PGF2alpha to regress existing CL and induce new ovulation (the rest)
    ○ 20% will be in heat -> won’t respond as no corpus luteum
    ○ 1st 5 days of ovulation also won’t respond -> 25%
  2. If give again 14 days later -> GET RID OF ALL CL
    ○ The cows not responding to 1st lot will now have corpus luteum and respond
    ○ Others who were in 1st 5 days will now be in heat and ready to mate so don’t need to work
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33
Q

What are the 4 steps in the offsynch cycle and what occurs in each group and what conception rate does it result in

A
  1. Give GnRH 12 days after last PGF2alpha
    Group A - Cause ovulation in cows that have LH receptors and large follicles
    Group B - Or increase LH levels but without ovulation as don’t have enough LH receptors
  2. 7 days after this give PGF2alpha
    Group A - regress new CL from previous GnRH injection
    Group B - Those that didn’t have enough LH receptors should have ovulated by themselves and have CL which need to regress
    - Now should all be luteolysis
  3. 2 days later give then GnRH
    BOTH - ovulation of the dominant follicle
  4. 16 hours later INSEMINATION -> sperm in tract before ovulation (occurs in 24-32 hours)
    - Results in 30-40% conception
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34
Q

What is the main cycling technique used in horses, why and the 2 drugs

A

use ovulation induction

  • only have to breed a mare once, expensive but thoroughbred stallions are very busy
    1. human chorionic gonadotropins (HCG)
  • acts like LH therefore need the LH receptors
    2. GnRH analogue
  • common, more expensive, mare ovulate between 42-48 hours if given as soon as largest follicle is 30mm
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35
Q

What is involved in the whitten effect (ram effect) and how use

A
  • If ewes are joined outside the breeding season can be used to stimulate oestrus
  • Ram pheromones need to be kept away from ewes for at least 1 month
  • Once join ewes that have been isolated will start cycling - whitten effect
  • If using AI can use teasers that can be used instead of intact rams and can put a marker on to see which ewes are on heat as they have been marked by the teasers (vasectomised)
  • Most ewes come into heat 17-25 days after first ram or teaser introduction
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36
Q

What are the 2 main ways seasonal breeders can be modified and what occurs in mares and sheep

A
  • Small ruminants can either be kept inside where light manipulated on order to stimulate shorter days or melatonin implants (stimulate the hypothalamic-pituitary axis)
    1) mares
    2) sheep
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37
Q

What occurs with mares in terms of changing their oestrus cycle

A

artificially extended day length most common
- Kept under a 16 hour regimen from about 1st June
- Brings about 2 months advantage in the onset of first ovulation of the season
§ Mares still will go through a period of “transitional oestrus” -> mare undergo at least 3 follicular waves of follicular growth without the occurrence of ovulation

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38
Q

What occurs with sheep in terms of changing their oestrus cycle

A

mainly use melatonin -> need to increase

- To control timing of lambing -> may do spring and autumn lambing

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39
Q

What are the 3 major steps in artifical insemination

A
  1. Collection of semen from the male
  2. Preservation and extension of sperm
  3. Insemination of the female
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40
Q

Semen extender what is its function, what has within and the 3 main reasons it is used

A
  • Added to protect the sperm if not inseminated immediately
  • Provides nutrients and cooling buffers if the semen in to be cooled
  • If frozen at cryoprotectants have to be added
  • Generally has -> buffer, energy in form of sugar and antibiotics
    Semen extender is used for multiple reasons:
    1. - Ejaculate can be split into multiple doses
    2. - increases longevity of sperm outside the reproductive tract
    3. - allows shipping of semen (overnight if fresh chilled; for any amount of time if frozen)
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41
Q

What is the duration of days that sperm remain fertile in the female reproductive tract for cows, mare, bitch and women

A

Cow - 1.5 - 2
Mare - 4-5
Bitch - 9-11
Woman - 5-6

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42
Q

What is involved with fresh vs frozen sperms

A

Frozen - can stay indefinitely but lose sperm during freezing and thawing process so need larger amount
Fresh - timing has to be better (within 24 hours)

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43
Q

Sperm sexing what is involved, how done and accuracy

A
  • Separation of X and Y bearing spermatozoa by flow cytometry
  • X chromosome has more DNA therefore and takes up more dye, emits more light and therefore computer reads as X sperm directing it to one side while Y sperm to another
  • Close to 90% accuracy
44
Q

Reproductive technologies list and describe 6

A
  1. Classic in vitro fertilization (IVF) -> egg and sperm are incubated together in small petri dish
  2. Intracytoplasmic sperm injection (ICSI) -> injecting one sperm into the egg
  3. Gamete intrafallopian transfer (GIFT) -> egg and sperm are transferred into uterine tube
  4. Embryo splitting -> take one egg with only a few cells and split get two eggs
  5. Somatic nuclear transfer (SCNT) -> nucleus from a donor adult cell is transferred to an egg that has been enucleated, when divides normally it is transferred into uterus of surrogate mother
  6. Embryo transfer -> allows dam to have more offspring in a given year therefore allows propagation of genetically valuable individuals
    - More common in bovines
45
Q

Avian reproduction where gonads, do they have a penis and what are the sex chromosomes

A
  • Internal gonads – both sexes - site in front of the kidney
  • Males – no Penis (* some have a phallus -> ducks, emus)
  • Males ZZ, Females ZW chromosome
    ○ Female are heterozygous
46
Q

What is the cloaca made from (3 areas) and what is important about it

A
  1. coprodeum
  2. urodeum -> reproductive tract, ureters
  3. proctodeum -> final area
    Urine, eggs and faeces, shoudln’t have any faeces or lumps and bumps
47
Q

Avian female anatomy what is variation in species with ovary and is there a CL

A
  • Only left ovary and oviduct in most species
  • Kiwi have 2 ovaries, raptors have right ovary
  • No corpus luteum is formed after ovulation -> don’t need to support placentation
48
Q

What are the 5 main ways to sex a bird

A 
colour 
- Sere (on the nares) -> budgie 
	○ Male -> blue 
	○ Female -> brown
- Electas parrot  
	○ Male = green 
	○ Female = red 
2. DNA PCR  
3. X-ray - hard to differentiate inactive gonads 
4. endoscope -> lateral approach in front of right hip 
5. lay egg -> FEMALE
49
Q

What occurs in each stage of the avian female reproductive tract

A

1) Infundibulum -> catches the ovum and bring into oviduct
- If miss move into abdomen cavity (resorbed)
2) Chalazae -> membrane attachments to hold the yolk centrally
3) Magnum -> produces the egg white -> thick on inside near yolk and thin on outside
4) Isthmus -> shell membrane -> 1 wraps around whites, within the inside of the egg shell
5) Uterus -> shell is deposited
6) Vagina -> close to keep oviduct sterile, until lay then relax and open

50
Q

What is the main endogenous and 4 main exogenous cues for avian reproduction

A

1.) Endogenous cues
- biological cycles – hormones, behavioural controls (migration etc)
2). Exogenous cues
1. Predictive factors – encourage gonads to prepare for breeding
○ e.g. photoperiod (chicken), rainfall (desert species)
2. Essential supplementary factors
○ e.g. social cues, nutrition (increased energy, protein, vitamins), rainfall, nest site availability
3. Synchronising factors
○ e.g. social interaction between pair - courting
4. Modifying factors e.g. loss of mate, disruption of nest (modifying factor, negative or reset - build new nest)

51
Q

What is vitellogenesis

A

making of the egg yolk in avian reproduction

52
Q

What is brooding and what hormonal changes occur

A

Decreasing levels of hormones such as oestradiol, LH, progesterone induces “broodiness” where hen stops laying and incubates eggs

53
Q

Calcium metabolism in birds, what needed for, what occurs during lay and how compensate

A
  • Calcium for shell sourced from diet or from skeleton
  • During lay, dietary calcium needs to be 3-4% for the majority of calcium to come from intestines
  • Vitamin D3 promotes calcium absorption from intestines and deposition of medullary bone
  • A laying bird can use its entire serum calcium in 15 minutes
    ○ Medullary bone is a buffer for maintaining serum calcium
    ○ When medullary bone exhausted cortical bone is used
    § Excessive loss of cortical bone -> osteoporosis -> not desirable
54
Q

What occurs pre and during lay for birds to reach calcium requirement

A

Pre-lay
- Birds will seek out calcium rich food prior to lay
- Oestrogens and androgens prior to laying increases medullary bone deposition
- Radiographically, medullary cavity of bones becomes more radio-dense
During Lay
- Oestrogen and prostaglandins increase mobilisation of medullary bone and serum calcium.

55
Q

What are the consequences of running low in calcium midlay in a bird

A

○ Weak-shelled eggs -> change in shape, wrinkled, possibly get infected -> Reduced hatchability
○ Poor smooth muscle contractility
– > Dystocia

56
Q

Domestic chicken how often lay, sexual maturity, how long between eggs, #1 breeding cue and how many eggs per year

A
  • Continuous layer
  • Sexual maturity: 18-20 weeks
  • Cycle for an egg -> 24 hours
  • # 1 Breeding cue: PhotoperiodCommercial layers: 330 eggs/year
57
Q

Budgerigar how often lay, sexual maturity, #1 breeding cue and how many eggs how often

A
  • Seasonal, Determinant layer (set number of eggs laid in a clutch)
  • Sexual maturity: 3-4 months
  • # 1 Breeding cue: Rainfall and feed availability - natural environment is the desert bush
  • Lay 4-6 eggs, egg every 2nd day.
58
Q

Mallee fowl how often lay, clutch size, sexual maturity and breeding cue

A
  • Seasonal, determinant layer
  • Clutch: 15-25
  • Sexual maturity: 3 years
  • Breeding cue: rainfall while nest mound open (winter)
59
Q

List 5 main ways you can turn off laying in domestic pet birds such as a cockatiel

A
  • Reduce energy component in the food
  • GnRH agonist -> downregulate pituitary reacting to GnRH
  • Remove the nest box
  • 8 hour photoperiod -> cover the cage at certain times
  • May have mated with the person -> decrease courting behaviours such as feeding (others feed), stroking the bird
    Could also be mirror and fluffy toy
60
Q

what is the mechanism of an erection and what occurs in a musculocavernous and fibroelastic penis (which species has which)

A
  • Increase blood flow to cavernous tissue + decrease venous return = engorgement of erectile tissue
    ○ Results = erection
  • Musculocavernous penis = increase width, length and rigidity
    ○ Horse penis
  • Fibroelastic penis = some increase rigidity and straightening of sigmoid flexure
    ○ Ruminants and pigs
61
Q

Coitus in the dog what occurs

A
  • The male and female remain “tied” together due to:
    ○ Bulbus glandis remains engorged after the turns -> tied (nothing can be done until erection goes down)
    § Contraction of the muscle at the base of the penis prevent venosus outflow from the bulbus glandis
    § Also the sphincter muscle of the vulva constricts compressing the dorsal vein of the penis and preventing blood from leaving
62
Q

What are the 4 functions of the epidiymis

A
  • Water absorption
  • Spermatozoal transport
  • Blood-epididymis barrier
  • Spermatozoal maturation
    ○ Acquisition of motility
    § Structural changes -> if have proximal droplet (near the head) then malfunction here
    § Physiologic changes
63
Q

Spermatozoal motility how does it occur

A
  • ATP produced by mitochondria diffuse the entire length of the flagellum
  • Glycolytic enzymes have been identified in fibrous sheath and outer dense fibers – pathway is essential under anaerobic conditions
  • Possibly a adenlyate kinase shuttle may assist in rapid distribution of mitochondrial produced ATP
64
Q

Spermatozoal metabolism what occurs and why increase

A
  • Constant supply of energy required for cellular housekeeping
  • Aerobic and anaerobic capacity
  • Increased requirement with activated motility
  • Further increase required for hyperactivation
65
Q

What are the 3 main things that occurs in the immediate transport of sperm

A
  • Once sperm are deposited after copulation they are immediately exposed to a series of defence mechanisms from the female
  • Only the “best” make it to the site of fertilization.
  • introduction of semen there is always also an introduction of microorganisms, which originate from the male (e.g. outside of his penis) or the female herself (caudal vagina)
66
Q

What is involved with the immediate transport of sperm what occurs with the “best” making it to fetilisation

A

○ Immediately, some are lost retrogradely and others phagocytosed by neutrophils and macrophages.
§ Phagocytosis and retrograde transport are the two ways by which sperm are lost from the reproductive tract.
□ Neutrophils sequester under the mucosa of the vagina and uterus as a result of oestrogen exposure

67
Q

What occurs with the introduction of microorganisms through sex

A

○ From about 3 hours of semen deposition a marked neutrophil reaction happens and they are not only attacking microorganisms but also sperm and the seminal plasma (needs to be removed doesn’t remain in the uterus)
§ They do not distinguish between live and dead spermatozoa and can phagocytose multiple sperm
§ The inflammatory reaction usually resolved within 48 hours
□ If not leads to post-breeding endometritis = “post-mating induced endometritis (PMIE)”, common condition in mares

68
Q

What occurs in the cervix in terms of sperm if it is deposited in the vagina

A
  • Oestrogen leads to production of sulomucins from the apical portion of the cervical mucosa, viscous substance directed towards lumen in caudal direction, if sperm get into this they are flushed out
  • Privileged pathways -> less viscous substance, sialomucin, is produced in the cervical crypts and facilities easier transport route for the sperm
    ○ Removal of non-motile sperm -> sperm have to be actively swimming through the mucus
    ○ Removal of some abnormalities
69
Q

What occurs in the sperm in the uterus

A

1) Capacitation initiated -> decapacitated sperm are not fertile
○ Plasma membrane of epididymal spermatozoa contains complement of surface molecules
○ If sperm is ejaculated they get into contact with seminal plasma and surface molecules get coated by seminal plasma proteins
○ When sperm exposed to the female tract environment the seminal plasma molecules and surface molecules are removed
§ They then expose portions of molecules, which are able to bind to the zona pellucida -> why is necessary
○ It is important to note that capacitated sperm can become decapacitated if incubated in the appropriate media (e.g. seminal plasma)
2) Phagocytosis

70
Q

What occurs in the oviduct in terms of sperm during sex

A
  • Rapid and sustained transport of sperm in oviduct
    ○ Caused by strong contraction of the uterine muscle in response to copulation
    § Dam’s oestradiol and prostaglandins in the semen (PGF2alpha and PGE1
  • Not just the first in oviduct fertilises the egg
    ○ Important transport seems to be the slow “trickle” of sperm that come from reservoirs in the cervix and the uterotubal junction (UTJ)
    § Maybe to avoid the initiate inflammatory reaction
71
Q

What are the 3 series of events during fertilisation that leads to them becoming fertile

A

1) Hyperactive motility -> in ampulla the pattern changes from a straight line to not linear, random movement -> more likely to bump into egg
2) Bind to zona pellucida -> sperm zona binding region (ZBR) reacts with Zona pellucida protein 3 (ZP3) and causes physical attachment of the sperm -> leads to acrosome reaction 3) acrosome reaction -> membrane overlying the acrosomal membrane begins to fuse with outer acrosomal membrane, leads to vesiculation and pore formation so acrosomal contents can reach the zona pellucida and facilitate sperms penetration through it -> need multiple sperm to produce enzymes that help break down zona pellucida (more than one sperm binds but only one sperm enters)
§ After acrosome reaction the vesicles slough and the inner acrosomal membrane and the post-nuclear cap are left behind

72
Q

What occurs once the sperm are fertile, how does it fertilise the egg

A

1) spermatozoon penetrates -> the sperm equatorial membrane fuses with oocytes plasma membrane and the sperm is engulfed
§ Leads to cortical block which is critical to prevent polyspermy (more than one sperm fertilising an egg)
□ Cortical granules are released into perivitelline space resulting in impenetrable zona pellucida
2) male and female pronuclear form -> after fusion sperms nuclear membrane disappears and the nucleus decondenses and male pronucleus formed
§ Male pronucleus then fuses with female pronucleus -> Syngamy -> successful fertilisation
Generally lots more fertilisation then pregnancies -> lots can go wrong after this point

73
Q

What is the conceptus

A
  • Everything that develops from zygote “product of conception”
  • Embryo/foetus
  • Extra-embryonic membranes
    ○ Amnion
    ○ Allantois
    ○ Chorion
    ○ Yolk sac
74
Q

what is the embryo

A
  • Organism in early stages of development (blasturation, gastrulation and organogenesis)
  • Usually not yet identifiable as membrane of a species
75
Q

what is the foetus

A
  • Controversial definition: often just “more advanced form of an embryo”
    ○ Can be recognised as member of the species
    ○ OR
    ○ From organogenesis to term
  • Foetal stage ends with expulsion from uterus -> neonate
76
Q

What are the 5 main steps after fertilisation to attachment

A

1) development within zona pellucida
2) hatching of the blastocyst
3) formation of the extraembryonic membrane
4) maternal recognition of pregnancy
5) attachment

77
Q

What are the 3 main steps with the development within the zona pellucida

A

1) large amount of cytoplasm present in the ootid (ootid= stage when male and female pronuclei are present in the oocyte); from here on cytoplasm will only be partitioned in embryonic cleavage (not more generated); once pronuclei fuse, the oocyte is called a zygote
2) First cleavage generates a 2-cell embryo whose cells are called blastomeres
3) Blastomeres then undergo division -> 4, 8, 16-cell phase

78
Q

what occurs in the development within zona pellucida 8 cell phase

A

§ At 8 cell embryo are totipotent -> at this stage each cell can form a foetus
□ Identical twins are derived if a 2-cell embryo splits and each blastomere develops independently into offspring - monozygotic
® Heterozygous twins -> double ovulation and both fertilised - different mechanism

79
Q

what occurs in the development within zona pellucida 16 cell phase

A

§ At 16 cell phase the embryo is known as morula
□ Outer and inner cells become compacted to two distinct cell population -> outer and inner cells
® Inner cells - develop gap junction (cavity) which facilitate cell-to-cell communication
® Outer cells - develop tight junctions (cell to cell adhesions)
□ Sodium pump believed to be responsible for increase in sodium in water within embryo -> form fluid filled cavity formed called blastocoel

80
Q

What occurs with the development within the onal pullucida and once the distinct cavity is formed

A

§ Once distinct cavity is visible the embryo is called a blastocyst
□ Inner cells - form inner cell mass (ICM), which give rise to embryo proper
□ Outer cell -> form the trophoblast cells, which give rise to the chorion (foetal part of the placenta)

81
Q

Hatching of the blastocyst what are the 2 main stages and the 3 main things that allows this to occur

A

1) Rupture of the blastocyst
1. As cells keep undergoing mitoses and fluid inside increasing the pressure within the zona pellucida
2. Outer trophoblast cells producing proteolytic enzymes, weaken the zona pellucida
3. Blastocyst contracts and relaxes causing pressure pulses
2) Blastocyst then hatches from zona pellucida
§ Once hatch undergo rapid growth

82
Q

location pre and post hatching of the blastocyst

A
  • Everything before hatched blastocyst are in the oviduct

- Past this point go into uterus and further development there

83
Q

What are the 6 steps in the formation of the extraembryonic membranes

A
  1. Thin lining beneath the inner cell mass (becomes the embryo) grows around the blastocyst cavity
    § Forms Endoderm and mesoderm
  2. Once endoderm finished growing it has form the yolk sac
    § Mesoderm starts growing outwards
  3. Mesoderm grows and pushes against trophectoderm (previously called trophoblast cells)
    § formation of little “wings” around the embryo, called amniotic folds -> folding of the amnion -> formed from ectoderm and mesoderm
  4. Mesoderm now surrounds the yolk sac and amniotic folds continue to grow upwards around embryo
    § The allantois forms as an outgrowth from the embryonic hindgut
  5. Yolk sac regresses, allantois grows, amniotic folds grow and eventually fuse
  6. The amniotic folds join above the embryo, forming the amniotic cavity right around the embryo.
84
Q

Maternal recognition of pregnancy in ruminants what are the 2 main mechanisms

A

§ Has the countercurrent mechanism therefore PGF2alpha needs to be prevented
□ The free floating (thread-like) blastocyst secretes interferon-τ (ovine and bovine IFN-τ, respectively), which binds to the endometrium and prevents oxytocin receptor synthesis.
® Remember that OT-receptors are critical in the process of luteolysis. So preventing OT-receptor synthesis, prevents PGF2α production.
□ IFN-τ also stimulates uterine gland secretion and therefore provides embryonic support. It is NOT luteotropic, meaning it does not directly act on the CL to enhance its function.

85
Q

Maternal recognition of pregnancy in ruminants what is needed, what occurs in conceptus present or without a conceptus

A

§ The pregnancy needs to establish ipsilateral to the corpus luteum (CL) for this to work successfully
□ Otherwise PGF2α will be produced from horn closest to CL and CL will be lost.
- If no conceptus present
§ luteolysis occurs at around day 15/16, progesterone levels drop and the cow will return to oestrus within a few days
- If conceptus is present and maternal recognition was successful
§ progesterone stays elevated because luteolysis don’t occur
§ Oxytocin receptor expression is blocked by IFN-t and therefore PGF2alpha secretion is not sufficient to induce luteolysis

86
Q

why is maternal recognition different in the pig

A
  • Pig is different from ruminants as even pregnant animals, PGF2alpha is produced DOES NOT REACH THE OVARY THOUGH doesn’t have the counter-current exchange
87
Q

what occurs when pigs don’t get pregnant

A

§ Oxytocin is produced and promotes PGF2alpha production by the endometrium
§ PGF2alpha diffuses to the capillaries and is drained to uterine vein, the transported to ovaries and cause luteolysis

88
Q

what occurs in terms of maternal recognition if pig is pregnant

A

§ The blastocyst produce oestradiol that causes PGF2alpha to be rerouted into the endometrium
□ Instead of reaching blood vessels in the endometrium (and CL’s) as in non-pregnant it is put into the lumen of the endometrium and has NO EFFECT ON CL
® Need to reroute all PGF2alpha produced and at least 2 blastocysts (conceptus) need to be present IN EACH HORN, so 4 in total - exam question
◊ If less than not enough oestradiol is produced by the conceptuses and luteolysis occurs

89
Q

What occurs with maternal recognition in the horse

A

§ Blastocyst does not elongate but instead stays in a spherical shape where stays for 15-16 days
□ Due to embryo surrounded by tough glycoprotein capsule -> surrounds the zona pellucida
§ In order to make contact with the endometrium and prevent PGF2α –production, the conceptus has to migrate all over the endometrial surface -> can move between uterine horns
□ Uterine contractions that move it
§ Between days 12 and 14 after ovulation (critical stage) it needs to make contact with every cm of the endometrium 12 to 14 times a day
□ If that does not happen, PGF2α is produced and luteolysis occur
□ Cysts within the uterine horn can prevent the movement of the conceptus and result in failure to recognise
§ After day 15-16 and have signalled presence will get stuck generally on the base of the uterine horn (fixation) and will lose the spherical shape as loss the outer tough glycoprotein capsule

90
Q

what occurs in terms of maternal recognition in canine

A
  • The progesterone profile in pregnant and non-pregnant animals is very similar
  • Every bitch goes either through pregnancy or pseudopregnancy after ovulation
  • Therefore, it is believed that no maternal recognition of pregnancy is present in the bitch.
91
Q

What are the 8 layers of teh scrotum, testis and epididymis

A
  1. Skin
  2. Tunica dortos (muscle)
  3. Fascia
  4. Parietal tunica vaginalis
  5. Visceral tunica vaginalis
  6. Tunica albuginea (covering the testes immediately)
  7. Mediastinum of the testis - where the rete testis sits
  8. Testicular parenchyma
92
Q

What are the 6 steps in teh movement of sperm from origin to penis

A
  1. Seminiferous tubules
  2. Rete testis (tube in the mediastinum)
  3. Efferent ductules (head of the epididymis)
  4. Duct of the epididymis
    ○ Where sperm matures, coils through the epididymis from the head -> body -> tail
  5. Ductus deferens (the sperm is mature at this point)
  6. Urethra
93
Q

What are the 4 layers of the seminiferous tubules

A
  1. Lamina propria with myofibroblasts (myoid muscle cells) on the outside
  2. Stratified germinal epithelium
  3. Spermatogenic cells or germ cells
    ○ release sperm into the lumen -> produce haploid cells
    § Mitotic and meiosis division
  4. Supportive (sertoli/sustentacular) cells
    ○ Irregular shape - elongated processes
    ○ Tight junctions
94
Q

What are the 5 main functions of the seminiferous tubules

A
  1. Provide a barrier between lumen and the rest of the body - immunological
    - Blood-testis barrier - tight-junctions
    □ Stop the body from sensing the presence of sperm - NOT SELF
  2. nutrients, protection and facilitate release of Spermatogenic cells
  3. hormones - regulation of interstitial endocrine cells
  4. phagocytic capability and engulf by products of Spermatogenic activity
  5. produce small amounts of oestrogen
95
Q

what is involved with the blood-testis barrier

A
  • Tight junctions between adjacent Sertoli cells create separate apical and basal compartments - boundary between these is the barrier
    ○ Basal region exposed to the body tissue environment -> multiplication of spermatogenic cells occurs here
    ○ Apical regions is isolated from the body tissue fluid and general humoral/immunogenic effects -> meiosis of germ cells and development of spermatozoa (spermatogenesis) occurs here
  • Each sperm passes through this barrier without causing disruption - cell junctions open and immediately close behind each cell
96
Q

rete testis, efferent ductules, duct of the epididymis and ductus deferens what made up of

A

Rete testis
- Lined by simple squamous to columnar epithelium
- Where most of the testicular fluid is reabsorbed in the head of the epididymis
Efferent ductules
- Lines by simple columnar epithelium with cilia (motility)
Duct of the epididymis
- Lines by pseudostratified epithelium comprising columnar principle cell with apical microvilli
- Convulsions of the epididymal duct are bound together in a connective tissue and muscle matrix enclosed by a capsule or tunica albuginea
Ductus deferens
- Thin muscular tubes mainly muscle and mucosa generally forms longitudinal folds
- Epithelium is pseudo-stratified columnar with brush boarder
- Tunica serosa that covers the surface is highly vascular

97
Q

What is the main thing used to synchronise cattle and how works

A

Progesterone and then PGF2alpha 7 days later

  • There are two groups in the cattle ones before ovulation and ones who have already ovulated
  • To bring them in synch need to do 2 things:
    1. Give progesterone initially -> the animals that are about to ovulate stop them from ovulating
    2. PGF2alpha 7 days later -> the animals that have ovulated and have corpus luteum accelerate luteolysis and shorten time to ovulation to catch up with the ones that are about to ovulate and have been stopped by the progesterone
98
Q

Define endometritis and metritis

A

Endometritis -> inflammation of the functional lining of the uterus (endometrium)
Metritis -> inflammation of the wall of the uterus -> full thickness of the uterus

99
Q

What is the difference in terms of when occurs for endometritis/metritis in cattle and horses (which has which)

A

CATTLE
- Generally occurs POST PARTUM
○ Open cervix, retained membranes, severe negative energy balance (everything they have into milk)
- Breed cows back 80 days -> have time for the metritis to have resolved
HORSE
- POST MATING ENDOMETRITIS
○ Normal!!! For a little while but if maintained after 48 hours then have an issue
§ Sustained inflammation can be infectious but NOT ALWAYS -> sterile post mating endometritis (do to issues with the anti-inflammatory cytokines)
- Breed horse back 10-21 days (after foal heat) -> less time to resolve the endometritis
○ ALWAYS BREED BEFORE OVULATION

100
Q

How to treat metritis in cattle

A

cattle - metritis

  • PGF2alpha -> some evidence of uterine contractions, gets rid of the corpus luteum with produces progesterone that is imunodepressant
  • Antibiotics -> get rid of the infection
101
Q

how to treat endometritis in horses

A
  • PGF2alpha -> some evidence of uterine contractions, gets rid of the corpus luteum with produces progesterone that is imunodepressant
  • Antibiotics -> get rid of the infection
102
Q

what precautionary methods should be put in place for next breeding if a mare has endometritis

A
  • Flush before service the mare - need to do within 30mins as otherwise will get inflammatory reaction to the saline
  • Flush with saline and give oxytocin -> at about 4 hours after mating (fluid should have left by now)
103
Q

what causes metritis in horses

A
  • Post-partum due to retained foetal membranes - occurs within hours
    Retained foetal membranes
104
Q

what are the 2 main ways to induce ovulation in horse and which is best

A

1) Give hCG in late Oestrus to induce ovulation - BEST

2) If give PGF2alpha in late dioestrus will just result in luteolysis but not ovulation for a few days so not used

105
Q

Dog pyometra what is it, when occurs, what most common cause and does it effect fertility

A

Pyometra -> infection of the uterus
- Is a metritis
- 6 weeks after heat - DIOESTRAL DISEASE
- E.coli until proven otherwise (more than 95%)
○ May be predisposed or infection of bacteria
○ Infection generally due to long immune suppression resulting from long canine dioestrus and prolonged progesterone
- Generally doesn’t lead to infertility

106
Q

what are the 2 main treatments for dog with pyometra and which is best

A
  • Spaying is the number one treatment option
  • Medically -> give PGF2alpha to induce contractions and removal of bacteria, also give antibiotics but not as important in PGF2alpha

DVM 2 - 2 (27 decks)

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