Repro Flashcards
Preformationism
Organisms develop from mini versions of themselves
Epigenesis
Organisms arose through series of stages produced from an undifferentiated mass
Aristotle
Described concepts of oviparity, viviparity, ovoviviparity
Harvey
‘Ex ovo omnia’ = everything comes from the egg
Steno
‘Testicles’ of woman were analogous to ovaries of the dogfish
Swammardam
All animals derive from eggs laid by same species. Spontaneous generation
de Graaf
Described follicle rupture in rabbits
Hooke
Coined the term ‘cell’
van Leeuwenhoek
Discovery of sperm
Bonnet
Described parthenogenesis in aphids
Spallanzani
Physical contact between sperm and egg
First AI in dogs
von Baer
First to observe & describe the oocyte
Newport
First reported entry of sperm into frog egg
Hertwig
Sperm-egg pronuclear fusion in sea urchin
Fol
One sperm required for fertilisation
Epididymis
Maturation of sperm during transit
Tube located behind each testis
Bulbourethral (Cowper’s) gland
Produces pre-ejaculate fluid to flush urine residue from urethra
Cryptorchidism
Failure of testes to descend when:
- Thermal needs not met
- Endocrine function not impaired
- Normal sexual drive but sterile
Cremaster muscle
Muscle that moves testes closer/further away from body to aid thermoregulation
Pampiniform Plexus
Network of small veins, countercurrent heat exchanger, cooling blood in adjacent arteries
Tunica Dartos
Muscles under scrotal skin
Contraction/relaxation in response to changes in scrotal skin temperature
Rete tubules
Transport newly formed sperm from testes to head of epididymis
Seminiferous tubules
Site of sperm production in testes
Leydig cells
Interstitial cells that produce testosterone
vas deferens
Duct transporting sperm from the tail of the epididymis to accessory sex glands
Vesicular glands (seminal vesicles)
Paired accessory sex glands responsible for major liquid portion of the final ejaculate
Libido
Sexual drive
Regulated by testosterone
Secretion of testosterone by Leydig cells controlled by:
LH from anterior pituitary
Production of spermatozoa controlled by:
Follicle Stimulating Hormone (FSH) through the action of Sertoli cells
Seminiferous tubules 2 cell types:
- Sertoli cells
- Developing sperm cells
Sertoli cells
Located in seminiferous tubules in the testes. Support developing sperm cells
Spermacytogenesis
Cell division
Spermatogonia
Undifferentiated male germ cell
Gonadotropin (GnRH)
Collective term for a hormone that stimulates ovaries, testes or both
Produced by hypothalamus
Stimulates release of FSH and LH from anterior pituitary
Hypothalamus
Part of the brain that secretes GnRH to the Anterior Pituitary
3 phases of Spermatogenesis
61 days in bull
- Proliferation (21d)
- Meiosis (23d)
- Differentiation (17d)
Proliferation
21d
Mitotic divisions of spermatogonia
Meiosis
23d
Meiotic division
Haploid spermatids
Differentiation
17d
Spherical undifferentiated spermatid to a fully differentiated spermatozoon
Sperm journey to accessory glands:
Testes, rete testis, efferent ducts, epididymis, vas deferens
Accessory glands
Prostate, vesicular, bulbourethral
Provides a liquid vehicle for the spz
Axoneme
Microtubule based cytoskeletal structure that forms the core of the flagellum in the sperm cell
Ejaculate volume - Stallion
50-100ml
Ejaculate volume - Bull
5-8ml
Ejaculate volume - Ram
1-2ml
Ejaculate volume - Boar
200-250ml
Sperm Collection Methods
- Artificial Vagina (AV)
- Electroejaculation
- Gloved hand (boar)
Electroejaculation
When males can’t be trained for AV or used in prepubertal animals
Controlled intermittent pulses of increasing voltage
- Low –> secretion from accessory glands
- High –> ejaculation
Haemocytometer
Used to count sperm cells during semen assessment
CASA
Computer Assisted Sperm Analysis - analysis of sperm motility
Live-dead ratio
Nigrosine eosin stain
Will only pass through membrane of dead/damaged sperm cells - shows dead cells
Compensable
eg. Reduced fertility may be overcome by increasing sperm number, i.e. can be fixed
Ivanov
Developed AI in Russia
Milovanov
Designed first AVs for bulls, rams, and stallions
Amantea
First AV in dog
Sorensen
First dairy coop
Perry
Published ‘The Artificial Insemination of Farm Animals’
Cassou
Invention of plastic straws for semen
Polge
Successful freezing of chicken sperm by including glycerol(prevents initial ice crystal formation) - cryoprotectant
Prentice
Head of American Breeders Service (ABS)
Developed Liquid Nitrogen containers with Linde for semen and embryo storage
Shannon
Caprogen - used for fresh semen storage (prevent cold shock)
Caproic acid and catalase + 5% egg yolk
AM/PM Rule
Established by Trimberger, rule for AI
Progesterone
Produced in CL on ovary
Maintenance of pregnancy
Prostaglandin
Produced in uterus
Responsible for regression of CL
Corpus hemorrhagicum
‘Comes from blood’
Newly formed CL
Corpus albicans
Old regressed CL
Follicles
Structure on ovary containing oocyte
Developing antral (tertiary) follicle
Called Antral due to presence of a fluid filled antrum
Secondary follicle
Follicle characterised by proliferation of surrounding granulose cells and deposition of the zone pellucida
Infundibulum
Funnel-shaped structure at ovarian end of oviduct that catches oocyte at ovulation
Fimbriae
Finger-like processes on the infundibulum to aid capturing oocyte at ovulation
Ampulla
Part nearest ovary
Isthmus
Part nearest uterus
Luteolysis
Process of CL regression
Duplex
Marsupials and rabbits
Bicornuate
Mare, cow, ewe
Simplex
Primate (human)
Oestrus
D0
Period of sexual receptivity/mating
Polyestrous
Cattle
Uniform cycles throughout the year
Seasonally polyestrous
Sheep, goat, mare, deer
Short/Long day breeders
Monoestrus
One cycle per year
Dogs
Follicular Dynamics
4 phases:
- Recruitment
- Selection
- Dominance
- Atresia
Inhibin
Produced by ovarian follicles; exerts negative feedback on FSH secretion
Ultimate fate of most follicles on the ovary
Atresia
Oestrous Cycle
- Oestrus (D0)
- Metoestrus (D1-4)
- Dioestrus (D5-18)
- Pro-oestrus (D18-20)
Metoestrus
D1-4
Post-ovulatory period
Dioestrus
D5-18
Corresponds to luteal phase
Follicular phase main hormone
Oestradiol
Luteal phase main hormone
Progesterone
Granulosa
Follicular cells that form large luteal cells after ovulation
Theca
Follicular cells that form small luteal cells after ovulation
Luteolysis
Regression of CL
Spermatic cord composed of
Pampiniform plexus, vas deferens & Cremaster muscles