Gametes And Gametogenesis Flashcards
What occur during prophase?
Chromosomes condense and DNA replication
What occurs during metaphase?
Chromosomes line up equator in a random order. Centrioles send spindles to attach to the chromatids.
What occurs during anaphase?
The chromatids are pulled apart
What happens during telophase?
The cells begins to split
What happens during cytokinesis?
2 new daughter cells are formed with their own cell membranes
How long does spermatogenesis take?
64-74 days
How many cells are produced a day during spermatogenesis?
300 million
Which hormone influences spermatogenesis?
Testosterone
What are the functions of serotoli cells?
To nourish and protect germ cell development. They envelope the developing spermatocyte and forms the blood-testes barrier.
What process occurs to produce spermatogonia from primordial germ cells?
Mitosis
What process occurs to produce secondary spermatocytes from primary spermatocytes?
Meiosis I
What process occurs to produce Spermatids from secondary spermatocytes?
Meiosis II
WHat happens to the daughter cells of mitosis in spermatogenesis?
One cell enters the resting state and the other enters meiosis I to maintain stem cell population
What is the function of the blood-testes barrier?
To prettiest genetically distinct cells
Why is protection via the blood -testes barrier required?
As the spermatozoon produces products that contain foreign antigens
What occurs in the process of Spermatids to spermatozoa?
- Spermatids decrease nucleocytoplasmic ratio
- Golgi vesicles form the acrosome
- Chromate condenses and the nucleus forms a spearhead shape
- Mitochondria migrate to the mid piece
Where is the spermatozoa stored?
In the epididymis
Where is the epididymis located?
Between the testicle and vas deferens
Where does maturation of the spermatozoa occur?
In the female reproductive tract
What is the purpose of oogenesis?
To produce oocytes from oogonia
How many oogonia are present at 4/5 months?
7 million
How many oogonia are present at birth?
600,000 - 800,000
How many oogonia are present in puberty?
Around 300,000
What must happen for production of the primary oocyte?
The cell must enter meiosis I
What do the squamous epithelial cells develop into?
Follicular cells
What makes up the primordial follicle?
The oocyte and follicular cell
What hormone will stimulate antral follicle production from the primary follicle?
FSH
What do follicular cells develop into during during folliculogenesis?
Cuboidal and stratified granulosa cells
When does the Zona pellucida develop?
During folliculogenesis
What does the secretion of oestrogen during folliculogenesis stimulate?
Fluid secretion by the granulosa cells and so polarisation of the primary oocyte
When does folliculogenesis occur?
At the beginning of the menstrual cycle
What does LH surge lead to?
Resumption of meiosis I to form a secondary oocyte and the first polar body. Expulsion of the oocyte ( ovulation).
When does meiosis II in the female gamete occur?
After fertilisation
What is the purpose of the corpus luteum?
To produce progesterone and oestrogen which stimulates growth of the endometrium
What upregulates oestrogen production?
Oestrogen production in the fecal cells
