Dr. Chibogu

Question 1

What is oogenesis

Answer 1

This is the production of the female sex gament

Question 2

What are the stages of ovum or oicyte developments

Answer 2

Primordial germ cell – Oogonium— primary oocytes — Secondary oocytes— ovum

Question 3

Where does oogenesis start from and when does it end

Answer 3

It start prenatally and end at the point of fertilization

Question 4

The whole process of oogenesis can be described in 3 stages

Answer 4

Stage 1 : Differentiation from primodal germ cell to — Oogonium

Stage 2 oocytogenesis
Oogonia / oogonium ____(mitotic division)– primary oocytes

The primary oocyte begin meiosis division and is arrested at prophase stage

Stage 3 Ootidogenesis
Ootic – chromosome has been half
The arrest has been removed and the first meiosis division is completed
To produce secondary oocytes

Secondary oocytes— undergoes 2nd meiosis to give rise to ovum at fertilization

Question 5

What us formed after the first meiosis

Answer 5

The Secondary oocytes—and 1polar cell

Question 6

What is the difference between polar body and oocytes

Answer 6

Cytoplasm size
Nuclear to cytoplasm ratio

Question 7

What is formed after the second meiosis division

Answer 7

Ovum and 3 polar bodies

Question 8

The total number primary oocyte in every mammal is determined or known at

Answer 8

Birth

Question 9

Developments from primary oocyte occurs when ?
Under the influence of ?

Answer 9

Occurs at Puberty

Influence of GnRH

Question 10

What happens to primary oocytes— at birth

Answer 10

They are encased in primodal follicle
What has a characteristics small shape and one layer of follicular cell (SQUAMOUS cell)

Question 11

What is the arrest phase (prophase 1 ) also called

Answer 11

Diplotene stage

Question 12

What causes the arrest at the prophase stage

Answer 12

Oocytes maturation inhibitor (OMI)

Question 13

What happens to follicle at Puberty

Answer 13

They developed from primodal to primary to

secondary to
graffian or pre- ovulatory follicle

Question 14

The second meiosis division get arrested at what stage

When is it released

Answer 14

Metaphase 2

Released at fertilization

Question 15

What is the end point of folliculogenesis

Answer 15

The release of secondary oocyte from the matured follicle

Question 16

What are the two types of ovulation based on stimulus that triggers the release of oocytes

Answer 16

Spontaneous ovulation
Induced ovulation

Question 17

What is spontaneous ovulation

Answer 17

Spontaneous ovulation occurs at natural events and occurs due to cycles
Without any extraneous or exogenous influence

Question 18

What ate the characteristic of spontaneous ovulation

Answer 18

1 Occurs at regular intervals
2. Hormonally controlled
LH. Leuthenizine hormone is what triggers ovulation
3. Estrogen is very important to the release of LH

Question 19

Examples of spontaneous ovulators

Answer 19

Cow , sheep, Goat, Dog

Question 20

Induced ovulation

Answer 20

There must be an external stimuli that triggers the increase of protrution of follicles

Question 21

Example of the chemical that can induce ovulation

Answer 21

Coitus
Chemical stimulus
Semen in the reproductive tract

Question 22

Examples of induced ovulators

Answer 22

Rabbit, cat, camel, elama

Question 23

Factors that affect ovulation rate

Answer 23

The rate of ovulation is genetically determined

Question 24

Factors that affect ovulation

Answer 24

Nutrition
Age
Season (seasonal breeder)
Social effect
Male effect

Question 25

What us coitus

Answer 25

Interaction btw male and female corpulatory organs

Question 26

What is corpulation

Answer 26

Physical union of male and female corpulatory organs involving intromission, thrusting with the aim to release semen in the reproductive tract

Question 27

Site of semen release

Answer 27

Horse – deep to the iterus

Cow —- at the vaginal

Pig – dip even as far as uterus

Question 28

What us fertilization

Answer 28

The union of male and female gament to form Zygote

Question 29

What are the 6 stages of fertilization

Answer 29

1. Spermatozoa and oocyte engagement
2. Acrosome reaction
3. Fusion of membrane
4. Oocyte activation
5. Formation of pronuclei
6. Symgamy

Question 30

Cortical reaction

Answer 30

This involves the movement of organelles (perisome, vacoules) to the peripheral of the cell membrane lead to zonal block

Question 31

Zonal blocks

Answer 31

Chemical interaction with the zonal pellucida that inhibits the engagement of any other sperm interaction
Preventing polyspermy

Question 32

Remember histosome

Answer 32

Yes
This are protein that pack the chromosome
Prof. Mrs alawa mention it

Question 33

When is the acrosome reaction said to be completed

Answer 33

Acrosome reaction is completed when the spermatozoa membrane lies within the perivitaline space

Question 34

Note about the sperm cell during fertilization

Answer 34

The sperm cell do not release their flagellum and mitochondria into the egg
The female mitochondria ends up powering the Zygote

Question 35

What do you see that confirm fertilization

Answer 35

Tail visibility
Presence of 2 pronuclei in cytoplasm
Cell division (2 cell in cleavage)

Then presence of polar bodies is suggestive

Question 36

What are the anomalies of fertilization

Answer 36

Polyspermy
Digynic polyploid

Question 37

What is polyspermy

Answer 37

Occurs when more than one sperm fertilize an ovum or egg
This results in an embro with two many chromosome which is usually not viable

Question 38

Digenic polyploidy

Answer 38

Digynic polyploidy happens when an egg with extra set if chromosome is fertilized by a normal sperm

This lead to an embro with 3 set of chromosome instead of 2 Chromosome
Condition leads to miscarriage or serious development issues