T3: Gamete Transport Flashcards
(52 cards)
what is the overview of sperm challenges
- transport
- capacitation
- hyperactivation
- chemotaxis/recognition
5.cumulus penetration - sperm-zona binding
- acrosome reaction
- egg penetration
- fertilization
how long does sperm transport through bovine and oviduct take
4-16 hours
how long does it take dead/defective spermatozoa to pass through the oviduct
15 mins
what are some barriers for the sperm
- vagina/cervix/uterus
-uterotubal junction
-isthmus/ sperm reservoir
what are some barriers to the oocyte
-follicle wall
-infundibulum
-ampulla
what are the semen depositions for species
vagina: cow, sheep, primates
cervical: mouse
intrauterine: sow, mare
what happens with the sperm in the cervix
spermatozoa migrate along the walls/ folds, not through the lumen
name the challenges for sperm deposition
-acidic PH in vagina (high lactate secretion)
-retrograde/backflow of semen
-long uterine body and horns
-leukocytic infiltration of uterus
what are the solutions to the challenges of semen deposition
-alkaline ph of seminal plasma
-cervical mucus serves as a vehicle for sperm and a filter for seminal plasma
-uterine muscle contractions increase in the late follicular phase
-timing of immune response to sperm is delayed (leukocyte infiltration occurs only after coitus)
what is included in immediate transport
-retrograde loss
-phagocytosis
-entrance into cervix/uterus
what is included/processes in the cervix
-privileged pathways
-removal of non-motile sperm
-removal of some abnormalities
what is included/processes in the uterus
-capacitation initiated
-phagocytosis
what is included/processes in the oviduct
-capacitation completed
-hyperactive motility
what is included/processes in fertilization
-acrosome reaction
-spermatozoon penetrates oocyte
-male and female pronuclei form
what are the two phases of sperm transport
rapid and sustained transport phase
what is included in the rapid transport phase
-within a few minutes sperm can be found in oviduct
-these sperm are non-viable and do not result in fertilization
what is included in the sustained transport phase
-trickle like delivery over hours
-these are the capacitated sperm that do not result in fertilization
what are the two types of mucous in cow
sialomucin: low viscosity and helps forward movement( helps create a privileged pathway: basal cells/ crypts
sulfomucin: high viscosity and washes sperm out: apical cells, cervical
what king of environment is important for the privileged pathway?
low viscosity environment in the valley of the cervix creates a “privilege pathway” for healthy spermatozoa
what are the challenges for the uterotubal junction/ solution
fold in mucosa (dead ends), viscous fluid, removal of seminal plasma, removal of defective/slow spermatozoa
solution: waves of contractions
what is the oviductal sperm reservoir and where is it present
binding of spermatozoa to oviductal epithelium in utero-tubal junction or isthmus
- present in cows, pigs, hamsters, sheep, mares
what are the proposed functions of the oviductal sperm reservoir
-maintenance of spermatozoa between the onset of oestrus and ovulation
-synchronization of sperm/ egg transport in oviduct
-prevention of polyspermy
-capacitation and hyperactivation
in cattle, earlier _____ reduces ______
earlier insemination reduces fertilization rates but increase embryo quality (timing difference between mating and ovulation
describe the binding of spermatozoa to oviductal sperm reservior
carbohydrate recognition is the mechanism, oviductal mucosa protects spermatozoa against aging and damage