gamete movments Flashcards
(29 cards)
slalomucin is produced fro what and what does it do
epithelium cells in the basal crypt, it provides a mucus that help move healthy sperm in the right direction
where are sperm lost in the reproductive tract
through retrograde transport and phagocytized by leukocytes.
what is retrograde loss of sperm
sperm of which travels in the wrong direction
the transport of sperm in the reproductive tract is spilt into two phases, what are they
rapid transport
sustained phase
where does fertilisation take place
isthmus ampulla junction complex
describe what occurs during the rapid transport phase
primarily controlled by the contraction of the muscularis and leads the sperm to the oviducts as fast as 5 minutes.
describe what occurs during the sustained transport phase
when the spermatozoa is transported in the oviducts in a ‘tickle like’ way from the cervix and the uterotubal junction. This delivers the sperm in a uniform manner to the ampulla.
how does the mucularis conrol movement?
Contractions are promoted in estrus due to high estradiol. however the semen hold postaganglin (PGF2a) which increase tone and motility of the uterus and oviducts.
what is the privleged pathway?
a filtration system of which allows the motile sperm to travel into the tracts, this pathway is supported by:
Sulfomucins - traps sperm with low motility or defectice structure. this secretion is dense
Sialomucins - promotes motiity, allowing healthy sperm to travel. this secretion has low viscosity
where are the Sialomucins and Sulfomucins secreted in the cervix
Sulfomucins - cervical crypts (privalaged pathway, promtes motlity into uterus), basal cells
Sialomucins - cervical canals (traps defective or weak sperm, apical cells
Some species have coagulating protein in the seminal plasma, why?
Causes a vaginal plug in the uterus after insemination, this prevents spermatozoa from undergoing retrograde flow to the exterior
how is the vaginal plug formed?
coagulating protein in the seminal plasma of the semen caus the mucus to clump together
how are sperm phagocytized by leukocytes
Neutrophils in the mucous of the vanigal lumen have increased production during estrus. This is to destroy any foreign bodies that are introduced during copulation. However the spermatozoa are also foreign bodies as will be phagocytized by the neutrophils.
acrosomal membrane rupture can be caused by what and how does it effect fertility.
the sperm will loose its enzymes and be unable to break into the zona pellucida.
acromsome breakage can be caused by Sudden heating/ cooling or pH change
what is capacitation
the changes of which spermatozoa undergo when in the female tract to allow for fertility.
describe the process of Capacitation
During the sperm mixing in the seminal plasma the sperm is coated with proteins, these proteins protect the surface molecules (proteins and carbohydrates). These proteins are stripped by the female tract environment with the surface proteins and carbohydrates.
Describe the changes that occur in the sperm cell during the acrosome reaction
Before the reaction the sperm membranes are all intact.
It begins with the plasma membrane and the spermatozoon forming multiple fusion sites with the outer acrosomal membrane.
As these two membranes fuse small vesicles are formed, this process is called vesiculation.
After vesiculation the acrosomes are dispersed and the nucleus is left covered in the inner acrosomal membrane.
Fertilization has a sequence of steps, what are they
Hyperactive motility
Binding to zona pellucida
Acrosomal reaction
Penetration of zona pellucida
Sperm-oocyte membrane fusion
Sperm engulfed
Decondensation of sperm nucleus
Formation of male pronucleus.
describe the hyper motility of sperm in fetilisation
Beginning in the oviduct the sperm change their pattern of movement,from a linear motility to a frenzied movement in the ampulla.
This is believed to facilitate oocyte - sperm contact
describe the binding of the sperm to the zona pellucida
Within the spermatozoa membrane there are proteins specific to binding with the zona pellucida.
These binding proteins must be exposed during the capitation process.
The sperm plasma membrane has two sites, the ‘primary zona binding region’ and the ‘acrosome reaction promoting liquid’
zona pellucida is made from glycoproteins , how many and what is the protein receptor in the sperm
zona proteins 1,2,3, (ZP1, ZP2, ZP3). NP3 is the receptor of the protein
what are the two plasma membrane site in the sperm
the ‘primary zona binding region’ and the ‘acrosome reaction promoting liquid’
the binding protein can only be exposed in the sperm after what process
capitation
describe what happens to the sperm during the acrosomal reaction
It begins with the plasma membrane and the spermatozoon forming multiple fusion sites with the outer acrosomal membrane.
As these two membranes fuse small vesicles are formed, this process is called vesiculation.
After vesiculation the acrosomes are dispersed and the nucleus is left covered in the inner acrosomal membrane.
