ERU: Reproductive Flashcards
What gene determines sex?
SRY gene
What hormone does the SRY gene produce and what are the effects?
Produces TDF. W/TDF = testes, without = ovaries
Seretoli cells
Testicular hormones in seminiferous tubules
- Produces cytokines (inclu. Anti-Mullerian hormone which causes Mullerian duct regression) + inhibin and minimal oestrogen
- Sperm mitosis
- Androgen receptors
Wolffian duct
Male
Mullerian duct
Female
Leydig cells
Testicular hormones btw seminiferous tubules
- Produce androgens (mostly testosterone to maintain Wolffian)
- Oxytocin
Androgens intra-teste function (3)
- Negative feedback on Leydig
- Myoid cells (smooth muscle surrounding seminiferous tubules)- help release mature spermatozoa
- Maintain spermatogenesis
Androgen extra-teste function (2)
- Irreversible effects when young is exposed at critical period, Masculinises the brain.
- Activational, reversible effects such as maintenance of spermatogenesis, anabolic effects, breeding season behaviours, etc.
Masculinization of female young examples (2)
- Twin calves, female is infertile due to androgens
- Female rodents between 2 males produce male-biased litters
Max temp of spermatogenesis
35C
Blood testes barrier
Formed by tight junction of sertoli cells. prevents diffusion between cells and not accessible by immune system
Role of sertoli cells in spermatogenesis
Mitosis of sperm cells in lumen created by sertoli cells, coordinates spermatogenesis and effects of FSH
Spermation
Mature spermatozoa
Pampiniform plexus
Venous plexus surrounding artery for heat exchange between body and testes
What hormone causes descent of testes?
Androgens. Effects on gubernaculum and suspensory ligament
Spermatogenic wave
Multiple stages at the same time ensuring continuous sperm production
Spermatogenesis stages: Spermatocytogenesis
1), Mitosis of spermatogonia
Spermatogenesis stages: Spermatidogenesis
2), Meiosis of spermatocytes
Spermatogenesis stages: Spermiogenesis
3), Differentiation- round and elongation of spermatids
Where do the testes develop?
Retroperitoneally near kidneys from intermediate mesoderm
Scrotal layers (out to in)
- Skin + Dartos muscle
- Cremaster muscle
- External spermatic fascia
- Internal spermatic fascia (parietal vaginal tunic)
- Vaginal cavity
- Visceral vaginal tunic
- Testes
Role of cremaster muscle
Adjusts position of testes (closer or farther away to body) to maintain ideal temperature)
Closed castration
Cut scrotal ligament (internal spermatic fascia and vaginal tunic intact)
Open castration
Cut lig of tail of epididymis
Corpus spongiosum
Around urethra
Corpus cavernosum
Paired, dorsal to urethra
What does the corpus cavernosum become in the dog? (SD)
Os penis
Musculocavernous penis
Flaccid: sympathetic, tonic muscle contractions around cavernous space
Errect: sympathetic inhibition, muscles relax, fill with blood
What muscles compress venous return in musculocavernous penis?
Ischiourethralis, Ischiocavernosus and bulbospongiosus
Fibroelastic penis
Flaccid: Retractor penis contracted
Erection: Retractor penis relaxes, flexure straightens
Mechanisms of copulatory lock
Swelling of bulbus glandis. Clamping of bitch’s vestibularis muscle on dorsal penile vein + superficial veins of glands.
Canine penis (SD)
- Pars longa glandis (distal)
- Bulbus glandis (proximal)
- Os penis
Stallion (SD)
- Mushroom
- Swap urethral sinus for CEM
Bull (SD)
- Glans flattened and twisted
- Broken penis
Ram (SD)
- Worm-like urethral process (urinary stones)
- Tuberculum spongiosum
Boar (SD)
- No glans
- Sub-urethral diverticulum (boar taint)
- Spiral
What are the accessory sex glands (4)
- Prostate
- Ampulla
- Vesicular glands
- Bulbourethral glands
Luteinisation
Formation of C.L
Effects of GnRH on oestrogen and progesterone
- High GnRH= High oestrogen
- Low GnRH = High progesterone
Monoestrous
Single oestrous cycle per year
Polyestrous
Successive oestrous cycles
Short-day breeder examples (2)
Sheep and goat
Long-day breeders examples (2)
Horse and cat
Non seasonal breeders examples (2)
Cow and sow
What happens to developing follicles during luteal phase?
Become atretic due to high progesterone
Oogenisis
Production of female gametes.
Primordial follicle
Primary oocyte, dormant
Primary follicle
Chosen to re-commence growth
Secondary follicle
Filled with antrum/ fluid-filled cavity
Preovulatory follicle/ Graafian
Chosen to mature to ovulation
Follicular waves
Group of follicles that continuously grow and mature. Only some fully mature.
Monovular species
Only 1 follicle matures
Polyovular species
Multiple ovulation
Describe the process of fertilisation
- Ovum released into uterine tube
- Captured by frimbraie
- Fertilisation at ampulla-isthmus junction
- To uterus
What causes luteolysis?
Prostaglandin F2a
What forms the ovarian bursa?
Mesovarium and mesosalpinx
Closed ovarian bursa
Small opening, Bitch
Open ovarian bursa
Able to see ovarian surface, Mare and Cow
Bovine udder suspensory ligaments (2)
Lateral suspensory laminae, Medial suspensory laminae
Arteries of bovine udder (3)
- External pudendal artery
- Sigmoid flexure
- Internal pudendal
Veins of bovine udder (2)
- Venous ring (to external pudendal) around base of udder
- Milk vein
Uterus types (3)
Simplex, Duplex, Bicornuate (Polytous species have more developed uterine horns)
Which ligament is stretched/broken during spay?
Suspensory ligament (ovary to dorsal body wall)
What comprises the broad ligament? (4)
- Mesovarian
- Mesosalpinx
- Mesometrium (uterine horn)
- Round lig (uterus to dorsal body wall through inguinal canal)
Blood supply to repro tract (3)
Ovarian, uterine and middle artery (large animals)
What can you feel in the middle uterine artery during pregnancy?
Fremitus (wizzing blood). You cannot palpate uterus after 6 months
Where does sperm bing in female as a “functional sperm resevoir”?
Utero-tubal junction
Sperm capacitation (2)
- Acrosome reaction (channels open)
- Activation (swimming pattern changes- whiplash)
Types of placentas (4)
Diffuse, cotyledonary, zonary, discoidal
What does the chorioallantoic membrane form?
Placenta
What does the allantois form?
Precursor to umbilical cord
