GAMETOGENESIS (Terms)

Gametogenesis

• Biological process by which diploid or haploid cells undergo cell division and differentiation to form mature haploid gametes

• Occurs by meiotic division of diploid gametocytes into various gametes

Four haploid (n); containing half as many chromosomes as the parent cell; genetically different

Gametogenesis ends with

• Produces gametes

• Reduces number of chromosomes by half

• Introduces genetic variability among gametes

Role of Gametogenesis

Two

How many cell divisions occurs?

Spermatogenesis

creation or production of sperm cell

Four

How many sperm will be produced at the end of Spermatogenesis?

TRUE

TRUE OR FALSE

Primary spermatocyte will undergo meiosis I and starts as DIPLOID

FALSE

TRUE OR FALSE

Secondary spermatocyte will undergo meiosis II and end as DIPLOID

Two

Primary spermatocyte will produce how many spermatocyte?

Four

Secondary spermatocyte will produce how many spermatid?

immature sperm (no tail)

Spermatoid

TRUE

TRUE OR FALSE

For an immature sperm to get a a tail, it will need to undergo spermiogenesis to become spermatozoa

Oogenesis

creation or production of egg cell

polar body and secondary oocyte

What does oogenesis produce?

Polar body

• excess daughter cell

  • will degenerate/combine with the secondary oocyte

  • OR will be utilized as a nutrient source

TRUE

TRUE OR FALSE

Only the secondary oocyte will undergo meiosis II

FALSE

TRUE OR FALSE

Maturation in the frog testis occurs from innermost to outermost

Spermatogonia

• usually found along the periphery of the tubule

• near the lining of the seminiferous tubule

• dark with no nucleus (only visible in mouse)

Primary spermatocytes

• largest among spermatogenic cells

• bigger w/ apparent nucleus

Secondary spermatocytes

• slightly smaller than primary spermatocytes; 

• some with highly condensed chromatin

• may nucleus at the middle

Spermatids

• very small, no distinct shape

• pinakamalapit sa lumen

• walang nucleus

Spermatozoa

• hair-like in appearance due to flagella; 

• either free in the lumen of the tubule or attached to Sertoli cell

• sperm exits the lumen

Sertoli Cell

helps in the maturation of sperm cell

TRUE

TRUE OR FALSE

The difference between mouse testis and frog testis is you can see the nucleus in the mouse’s spermatogonia while in frog’s you cannot see the nucleus

Follicle Cells

Cluster of spherical structures; helps with the maturation of the egg cell

Germinal Vesicle

Nucleus of primary oocytes; regulates oocyte growth

Vitelline Membrane

Outermost envelope surrounding the plasma membrane; appears as a thin dark line

Yolk-laden Cytoplasm

Food source of the embryo

Theca Folliculi Externa

Outer fibrous layer made up of collagen fibers

Theca Folliculi Interna

Inner cellular layer made up of cells that secrete androgens

Primary Oocyte

Large cell surrounded by follicle cells with small centrally located nucleus

Primordial follicles

primary oocyte for future follicle development

Theca cells

• cells forming around follicle;

• for androgen production & structural support.

Stratum granulosa

• multiple cell layers around oocyte & corona radiata;

• support follicle growth

Zona Pellucida

• acidophilic-staining glycoprotein material secreted by the primary oocyte and corona radiata that encloses the vitelline membrane;

• protects oocyte;

• mediates sperm binding

Corona radiata

• single layer of granulosa cells adjacent to oocyte;

• provides nutrient and metabolic support

Follicular cavity

• fluid-filled space;

• adjacent to oocyte;

• hormone diffusion

Cumulus oophorus

• “hillock” granulosa cell mound;

• connects oocyte to follicle wall

Antrum/antral cavities

fluid filled cavity adjacent to primary oocyte and corona radiata

Growing Primary Follicle

• has only one covering of the follicular cell

• containing the oocyte surrounded by the developing zona pellucida and an outer layer of granulosa cells that have become cuboidal;

Secondary Follicle

containing the oocyte surrounded by a thick, fully-developed zona pellucida, multiple layers of granulosa cells, the basal lamina, and two outermost layers of theca folliculi cells

Tertiary Follicle

• with a cavity (antrum) formed within the cumulus formed by granulosa cells. 

• At this point, some of the granulosa cells have remained surrounding the oocyte, forming the corona radiata external to the zona pellucida.

Ovulation

• process of releasing the egg cells

• every 14th day in humans.

• rupture of the follicle and release of oocyte

Corpus luteum

the follicutar structure left after ovulation.

FALSE

TRUE OR FALSE

Difference between frog and cat ovary is that frog ovary has corona radiata and corpus luteum while the cat ovary does not have.

Spermatozoa

Fate of the Spermatid