Lecture 08: Semen Deposition and Transport (Pozor) Flashcards
organs participating in semen formation
epididymis, ampulla, accessory sex glands
Where is disseminate prostate located in the ram?
within the pelvic urethra
Where does pathology of accessory sex glands occur most often in bulls?
inflammation of vesicular gland
NO role in sperm transport
helps develop erection of penis
What happens to veins during erection?
become compressed so blood can flow in but not out of penis, causing engorgement
Vascular penis and species
Will change in size/length during erection. Stallion
Fibroelastic penis with sigmoid flexure BEHIND the scrotum + species
- retractor penis m. relaxes, allowing sigmoid flexure to elongate
- penis elongates but does not widen during erection
- bull
species with Fibroelastic penis with sigmoid flexure CRANIAL to the scrotum
boar
os penis and species
- has bone
- more vascular tissue in glands and can enlarge
- Has bulbus glandis
- Dog
animal with Spines penis
Tom cat
emission and assoc. nerve reflex
release of sperm and accessory gland fluid into pelvic urethra. Controlled by thoraco-lumbar reflex which causes smooth muscle contractions
ejaculation and assoc. nerve reflex
forceful expulsion of the combined fluids from the urethra. Caused by sacral reflex
Detumescence and assoc. nerve group
diminishing of an erection (increased smooth muscle tone in corpus cavernosum/spongiosum; contraction of the retractor penis m.). Caused by sacral sympathetic nerves
which species penis is corkscrew shaped?
boar
fractions of semen in ruminanrs
1 jet (sperm rich fraction)
fractions of semen in equids
~3 jets sperm-rich, ~3 jets gel fraction
fractions of semen in swine
1 gel fraction, 1sperm rich fraction, then another gel fraction
fractions of semen in canine
sperm-poor fraction –> sperm-rich fraction –> prostatic fraction
which species ejaculate directly into the uterus?
boar (also cervix), stallion, dog, camelid
which species ejaculate into the vagina?
bull, ram, man, tom cat
retrograde loss
sperm loss due to natural outward flow out the vagina
major reservoir site for sperm in female
cervix
capacitation
Involves the destabilisation of the acrosomal sperm head membrane allowing greater binding between sperm and oocyte. Exposes the sperm so they are ready to penetrate the ova. Occurs in the uterus
Fx and causes of uterine contractility
Fx: propels “good” semen up uterine horns and ejects those that can’t swim
Causes: oxytocin, prostaglandin (in seminal plasma), estrogen (in seminal plasma)
Breeding-induced endometritis
spermatozoa induce inflammation and an influx of polymorphonuclear neutrophils (PMNs) into the uterine lumen
What hormone do PMNs release?
prostaglandin (to stimulate myometrial contractions and removal of bacteria causing endometritis)
3 major roles of seminal plasma once in female
1) decrease duration of inflammatory response
2) protects live sperm from PMN binding
3) promotes PMN binding with dead sperm
Normal site of fertilization in most animals
ampulla of oviduct
Sperm in the oviduct
- uterotubal junction = sperm barrier
- isthmus = sperm reservoir
- ampulla = site of fertilization
- infundibulum guides ovum
Role of isthmus in sperm storage
- stores sperm
- increases selection of fertile sperm
- prolongs sperm viability
- prevents capacitation
Cryopreservation effect on sperm
- may interfere with binding to oviduct
- removal of seminal plasma
- increases incidence of endometritis
assisted breeding deposits semen where?
directly in uterus
