Repro Week 1 Flashcards
What are the layers around the testis?
Tunis albuginea, visceral vaginal tunic, parietal vaginal tunic, scrotal fascia, tunica dartos, scrotal skin
What do Leydig cells produce?
testosterone
What is epididymal transit time?
Time taken for sperm to travel from proximal head to the distal tail of the epididymis
What does the ductus deferens do>
Connect the epididymis to the pelvic urethra
What makes up the spermatic cord?
Ductus deferens and testicular artery and vein, nerve and lymphatic supply
What is the purpose of the pampiniform plexus?
Heat exchange, pulse pressure eliminator, transfer of testosterone from testicular vein to artery
Which accessory glands does the dog have?
Ampulla and prostate
Function of seminal plasma?
Needed for dilution and delivery of sperm, contains fructose for energy source, coagulating in stallion and boar
What is the blood supply to the accessory gland, urethra and penis?
Internal pudendal
What are the erectile tissues?
Corpus cavernosum, corpus spongiosum
Which animals have a fibroelastic penis?
Ruminants and pigs
Where is the glans penis?
Opening of the urethra
What are the sex chromosomes in birds?
ZZ= male XW= female
What is the effect of oestradiol on the brain during development?
Masculinises the brain
What do the mesonephric ducts become in the male?
Epididymis and ductus deferens
What does hypospadias mean?
Urethral opening at base of penis
What is the action of the ischiocavernous muscle?
Forces blood into corpus cavernosum and corpus spongiosum
What is the role of parasympathetic neurones in erection?
Inhibit longitudinal muscle in helicine arteries, causing relaxation
What is the structure and function of a fibroelastic penis?
Much fibrous tissue, length is increased by straightening of sigmoid flexure as result of relaxation of retractor penis
What are the features of boar ejaculate?
First fraction= accessory fluid and few sperm
2nd fraction= rich in sperm
3rd fraction= thick coagulum
What occurs in metaphase?
Chromosomes arrange on the equator of the spindle
What occurs in cytokinesis?
Cleavage furrow forms and deepends until cytoplasm is halved, aided by a ring of actin filaments attached to the inner aspect of the cell membrane
What is the purpose of cyclin dependent protein kinases?
Intracellular control of mitosis- act as checkpoints
What is the action of Myc?
Increases expression of G1 cyclin kinases- stimulaiton of DNA synthesis
In what phase does crossing over occur?
Prophase 1- pachytene
From what cells do spermatogonia develop from?
Primordial germ cells
Where do primary oocytes arrest until puberty?
prophase I
What are the sources of genetic variation?
Independent assortment of chromosomes, recombination crossing over, mutation
How are X chromosomes inactived in females?
Methylation of the DNA and expression of antisense transcript
What is klinefelter syndrome?
Result of an extra chromosome in a male producing CCY
Where does spermatogenesis take place?
Seminiferous tubules
What is contained in the head of the sperm?
Nucleus, acrosome and post nuclear cap
What is the role of LH and FSH in the male?
LH- binds to receptors on leydig cells and causes production of testosterone
FSH- binds to receptors on sertoli cells enabling function, converting testosterone to oestradiol and producing inhibin
What is the time taken for spermatogenesis in the bull
61 days
What hormones does the placenta produce?
Prostaglandin F2a, progesterone, oestrogen, eCG, hCG
Describe the HPT axis
Pulses of GnRH resulting in pulses of LH which stimulate Leydig cells to produce testosterone there is negative feedback via inhibin to the pituitary and through testosterone itself to the hypothalamus
Where is semen deposited in the pig?
Cervix/uterus
What are the mucus secretions that aid sperm transport int ther cervix?
Sialomuciin and sulphmucin
Describe the acrosome reactino
Initiated by sperm binding to the zona pellucida involving release of acrosomal hydrolytic enzymes which digest the zona pellucida and form a small hole for the sperm to enter the egg
How long is sperm fertile for in the bitch?
9-11 days