Fertilization

Question 1

What two ways are sperm lost from the female tract?

Answer 1

Retrograde transport and Phogocytosis

Question 2

What do sperm undergo when they encounter the oocyte?

Answer 2

Acrosome reaction and fertilization

Question 3

What determines how much sperm is lost?

Answer 3

physical nature of ejaculate and site of deposition

Question 4

Where is semen deposited in the cow and sheep?

Answer 4

Anterior vagina

Question 5

Where is the semen deposited in the sow and mare?

Answer 5

Cervix

Question 6

What is unique about the seminal plasma in a stallion and a boar?

Answer 6

It’s very viscous and may help reduce the retrograde flow from the tract. The boar creates coagulum.

Question 7

How can the transport of sperm be divided?

Answer 7

Rapid and sustained phase

Question 8

Which transport phase is best understood?

Answer 8

Sustained

Question 9

How and where does the sustained phase deliver sperm?

Answer 9

Distally to the ovaries in a trickle fashion from reserves in the UTJ and cervix

Question 10

E2 stimulates contractions of what during sperm transport?

Answer 10

Muscularis of the myometrium

Question 11

What in the semen causes increased tone and motility of the uterus and oviduct?

Answer 11

PGF2a and PGE1

Question 12

What is unique about the seminal plasma of a boar?

Answer 12

It contains a protein that advances the time of ovulation

Question 13

Why would we choose to treat female pigs with compounds to minimize retrograde flow?

Answer 13

to alter the smooth muscle motility

Question 14

What are the two types of cervical mucus made by the cow?

Answer 14

Sialomucin and Sulfomucin

Question 15

Where are the two types of cattle cervical mucus produced and what is their viscosity?

Answer 15

Sialomucin- low viscosity and produced in the basal area of the cervical crypts
Sulfomucin- High viscosity and produced in the apical areas of the cervical epithelium

Question 16

Describe the rapid phase of sperm transport.

Answer 16

The rapid phase delivers sperm to the site of fertilization but aren’t viable

Question 17

Where does capacitation occur?

Answer 17

Cow and Sheep-as the sperm passes through the cervix

Sow and Mare- In the uterus and isthmus of the oviduct

Question 18

Can a single environment capacitate all sperm types?

Answer 18

No

Question 19

What goes through the marked biochemical changes during capacitation?

Answer 19

The plasma membrane of the sperm

Question 20

What happens when sperm are removed from the female tract and placed into seminal plasma?

Answer 20

The become decapacitized again

Question 21

What are the steps to fertilization after capacitation?

Answer 21

Hyperactive Motility
Binding o the ZP
Acrosome Reaction
Penetration of the ZP
Sperm oocyte membrane fusion
Sperm engulfment
Decondensation of sperm nucleus
Formation of male pronucleus

Question 22

Describe hyperactive motility

Answer 22

Occurs in the ampulla, causes them to move into a frenzied motion in search of the egg to increase contact

Question 23

What are the 3 glycoproteins in the ZP of the oocyte?

Answer 23

ZP1, ZP2, ZP3

Question 24

Which glycoproteins are considered structural?

Answer 24

ZP1, ZP2

Question 25

What is the purpose of ZP3 glycoprotein?

Answer 25

binds to proteins on the sperm membrane

Question 26

What two places are the sperm able to bind to on the egg?

Answer 26

Primary zona binding region

ARPR

Question 27

When sperm binds at the ARPR what does the ZP3 do?

Answer 27

Initiate acrosome reaction

Question 28

Where is the fusion protein and when is it activated?

Answer 28

At the equtorial segment

At vesiculation

Question 29

Do Damaged acrsomes vesiculate in an orderly fashion?

Answer 29

No they rupture all at once

Question 30

What purpose does acrosin serve?

Answer 30

Its an enzyme that hydrolyzes the zona proteins

Enhances sperm ability to bind

Question 31

What is the perivitelline space?

Answer 31

Space between the zona and the oocyte plasma membrane

Question 32

When is the spermatozoa engulfed in the process?

Answer 32

When the plasma membrane fuses with the equatorial segment

Question 33

What do cortical granules contain?

Answer 33

mucopolysacchrides, proteases, perioxidase, acid phosphate, plaminogen activator

Question 34

When do cortical granules move to the periphery of the oocyte cytoplasm?

Answer 34

During first and second meiotic divisions of oogenesis

Question 35

What are the two blocks included in fertilization and what specifically do they do?

Answer 35

Vitelline block- cortical reaction reduces the ability of oocyte membrane to bind to other sperm
Zona block- Exocytosis prevents polyspermy

Question 36

Describe the decondensation of the sperm nucleus.

Answer 36

Sperm nucleus enters the cytoplasm of the egg and becomes the male pronucleus.
Nucleus decondenses so that chromosomes pair up

Question 37

What is sygamy?

Answer 37

Fusion of male and female pronuclei