Sperm Transport Flashcards
After sperm penetrates the zona, they must fuse with the oolemma how does this occur?
- Sperm enters the perivitelline space
- Sperm is engulfed by the oocyte plasma membrane (requires fusion of equatorial segment and oocyte plasma membrane)
Epididymal + Seminal plasma starts what? Then what does ejaculated + female tract start?
- Ejaculated
- Capacitated
How are sperm lost in the female tract after deposition?
- Through retrograde transport
- Phagocytosis by neutrophils (WBC)- vagina and uterus
How does the process of sperm transport go?
- Immediate Transport
- Cervix
- Uterus
- Oviduct
- Fertilization
How many phases make up the sperm transport?
Two phases:
1. Rapid phase
2. Sustained phase
In natural mating where is the cranial vagina the site of semen deposition for in which animals? Which animal has a different effect?
- The animals these apply under are:
cow, sheep,rabbit primates, dog,cat,rodents. - Rodents have a gel plug for vagina, prevents retrograde sperm loss
In sperm- oocyte fusion what occurs?
After passing the zona, sperm are surrounded by a bed of microvilli on the oocyte plasma membrane
1. The oolemma of the oocyte fuses with the equatorial segment of sperm and then the sperm is engulfed
2. Cortical granules are released into the perivitelline space.
What are some functions of the cervix?
- Barrier = non-motile, abnormal & dead sperm
- Mucous secretion (amount varies between species) = different viscosities of mucous help to filter sperm
What are the post capacitation events that lead to fertilization?
Hyperactive motility -> Binding to zona pellucida-> Acrosomal reaction-> Penetration of zona pellucida-> Sperm-oocye membrane fusion-> Sperm engulfed -> Decpndensation of sperm nucles-> Formation of male pronucleus
What are the sequence of events that follow semen deposition?
- Immediate transport
- Cervix
- Uterus
- Oviduct
What are the two types of mucous in the cow?
There are:
1. Sialomucin
2. Sulfomucin
What do these acronmys mean:?
1. OAM
2. IAM
3. ARPR
4. ZBR
- Outer acrosomal membrane
- Inner acrosomal membrane
- Acrosome reaction promoting region
- Zona binding region
What happens to the plasma membrane that protect the sperm?
Plasma membrane proteinsa re removed in the female tract, which allows sperm to interact with oocyte.
What initiates Phagocytosis by neutrophils? What occurs during this time?
- Requires elevated strogen
- Prevents microorganisms from colonizing in tract
- Digest some sperm (foreign to female)
(No real negative effect on fertility)
What is acrosin and proacrosin part of?
Part of the process when sperm releases enzymes to penetrate the zona
What is Acrosin?
- It is when the zona proteins hydrolyze
- Promotes sperm penetration through the zona
What is proacrosin?
It is the inactive form of acrosin, aids sperm binding to zona during hypermotility
What is sperm capacitation?
- Series of structural and biochemical events that prepares sperm for fertilization
- Capacitation of sperm occurs over time and not every sperm capacitates at the same rate.
- Ejaculated sperm are coated with proteins from seminal plasma
What is the Sulfomucin?
High viscocity, secreted by apical epithelial portions of crypts, sperm washed out of tract with contact.
What is the rapid phase?
- It is when sperm reaches the oviduct within minutes after deposition
- These sperm do not fertilize eggs
What is the Sialomucin?
Low viscocity, secreted by basal cells of crypts, “priviledged pathway” for sperm to swim.
What is the sperm storage of a female called?
Sperm oviduct resovoir
What is the sustain phase?
- The sperm take longer to reach the oviduct
- They bind to the epithelium and are stroed for fertilization
What is vesiculation?
Vesiculation is a formation of of vesicles due to membrane fusion
1. It is whereacrosomal contects dispersed
2. Enzymes allow sperm to digest zona (small hole)
What occurs during the acrosome reaction?
It is a fusion of plasma membranes
1. Enables zona pentration
2. Enables equatiorial segment to fuse with oolemma (oocyte plasma membrane)
What occurs during the capacitated level of sperm?
One step of capacitation is to remove some surface proteins & carbohydrates so the underlying acrosome can penetrate the oocyte
What occurs during the ejaculated aspect of sperm?
Seminal plasma contributes to sperm plasma membrane proteins
What occurs in the cervix?
There is:
1. “privileged” pathways
2. removal of non-motile sperm
3. removal of some abnormalities
The cervix facilitates selection of sperm by removing non-motil sperm and those with abnormalities to prevent transport.
Defective
What occurs in the epididymal stage ?
Plasma membrane of epididymal sperm contains surface proteins and carbohydrates.
What occurs in the immediate transport ? What are its factors?
- Sperm either gets transported, and are lost due to retrograde flow, or are phagocytosed
- Retrograde loss
- Phagocytosis
- Entrance into cervix/uterus
What occurs in the immediate transport?
There is:
1. Retrograde
2. Phagocytosis
3. Entrace into cervix/uterus
Sperm either gets transported, or are lost due to retrograde flow or are phagocytosed
What occurs in the oviduct in the events following semen depostion?
There is:
1. Capacitation completed
2. Hyperactive motility
The uterus induces structual changes of the sperm in preparation for fertilization (4 hours roughly)
What occurs in the uterus in the events following semen deposition?
There is:
1.capactiation initiated
2.phagocytosis
Sperm must reside in the female tract before they acquire maximum fertilization potential.
What occurs when there is an exposure of sperm equatorial segment?
It fuses with oocye membrane
What starts capacitation?
The outer and inner leaflets combines together to start it.
when does the acquistion of hyperactivity happen and what occurs?
- Occurs in the ampulla of the oviduct
- Sperm change from a relatively linear motion to an increase in velocity
- Faciliates sperm-oocye interaction and zona penetration
Where is natural semen deposition placed in the horse? How is gel fraction useful?
1.In the cervical lumen in the uterus (“squirted through the cervical lume”)
2.Gel fraction decreases retrograde sperm loss
Which animal has a site of semen deposition (in natural mating) in the cervix? What prevents retrograde sperm loss?
- The pig
- The gel fraction is what helps prevent retrograde sperm loss
Which animals after artificial insemination have semen deposition in the intracervical location? Which one is in the intravaginal?
- Sow
- Dogs & Cats
Which animals site of semen deposition in artificial insemination is in the Transcervical?
The animals are
* The mare
* Cow
* Sheep
When sperm is in the process of going through oocye fusion what occurs to the sperm?
- The sperm nuclear membrane dissolves
- Sperm nucleus begins to decondense
What is the purpose of the zona block? What does it consist of?
- Purpose of the zona block is to prevent polyspermy
- Consits of exocytosis of cortical granules from the cytoplasm into the perivitelline space.
What is the purpose of the zona block? What does it consist of?
- Purpose of the zona block is to prevent polyspermy
- Consists of exocytosis of cortical granules from the cytoplasm into the perivitelline space.
What happens after the sperm nucleus decondenses?
- After sperm nucleus enters the cytoplasm of the egg it becomes the male pronucleus
- The male pronucleus must “decondense” and lose the disulfide bonds that were stabailizing DNA
- Decondensation, reduction of disulfide cross-links and loss of protamines in sperm are required so chromosomes of the male pronucleus can pair with the female pronucleus
- Glutathione in the oocyte cytoplasm reduces disulfide bonds in sperm
- The male and female pronuclei can fuse in an event known as syngamy and embryogensis can begin.
How long is sperm viable in these female tracts?:
1. Bitch
2. Camelids
3. Cow
4. Mare
5. Woman
- 9-11 days
- 4-5 days
- 1.5-2 days
- 4-5 days
- 5-6 days
What is parthogenesis? Which animal usually has this?
- It allows 2 polar bodies which can make a complete set of offspring
- Reptiles
What is superfecundation?
Multiparous species can have litters of multiple paternities
When it comes to the bitch what is different about litter variation?
- Bitch is mated by several males during estrus
- Sperm from all males can fertilize oocytes
- Litters of different breeds
How long is the life span of oocyte within a woman?
24 hours
When it comes to conceptus in women what does the process consist of?
Conception can occur over 6-7 days window “fertile period” because sperm are stored
1. 5 days preovulation + 2 days post ovulatio
2. Closer copulation is to ovulation increases chance of pregnancy
Semen deposition in the mare is __________.
Intrauterine
Semen deposition in the sow is ___.
Intracervical
Semen deposition in the bitch is ____.
intravaginal
Semen deposition in the cow is ___.
Intrauterine
