Gametogenesis Flashcards
Define gametogenesis?
Production of gametes from haploid precursor cells
What is the formation of sperm called?
Spermatogenesis
What is formation of egg called?
Oogenesis
State location, equal or unequal meiotic divisions, germ line epithelium for
1) Spermatogenesis
2) Oogenisis
Spermatogenesis- all in testes
- equal div cells
- involvement germ line epithelium
Oogenesis- mostly ovaries
- unequal div cytoplasm
- no involvement germ line epithelium
State number of gametes produced as well as size for:
1) Spermatogenesis
2) Oogenesis
Spermatogenesis- 4 gametes
- sperm smaller then spermatocytes
Oogenesis- 1 (2-3 polar bodies)
- ova larger oocytes
What is stage before sperm called?
Spermatocyte
State duration, onset, release and end of:
1) Spermatogenesis
2) Oogenesis
Spermatogenesis- uninterrupted
- begins puberty
- continuous release
- life long
Oogenesis- arrested stages
- begins foetus
- monthly puberty
- terminates menopause
Fill in table for spermatogenesis and oogenesis?
What cells important for sperm production?
Sertoli cell
Define spermatogenesis?
Process where sperm cell production occurs; germ cells give rise to haploid spermatozoa
Where does sperm production occur?
In seminiferous tubules (in testes)
Outline steps in spermatogenesis?
1) Spermatogonum 2n
2) Primary spermatocytes 2n
3) Secondary spermatocytes n
4) Spermatids n
5) Spermatozoa (sperm)
When does meiosis 1 and 2 occur in spermatogenesis?
Meiosis 1- primary spermatocyte to secondary spermatocyte
Meiosis 2- secondary spermatocyte to spermatids
What is formed at end of spermatogenesis?
Spermatozoa
Draw flow diagram of spermatogenesis?
Where does oogenesis occur?
Ovaries
In gametogenesis does meiosis or mitosis occur?
Mitosis- start
2 divisions via meiosis- gametes contain half number chromo as parents
Outline process of oogenesis?
1) Oogonium 2n
2) Primary oocyte 2n
3) Secondary oocyte and primary polar body n
4) Ovum and 3 secondary polar bodies n
When do meiotic division occur in oogenesis?
1) Primary oocyte (arrested prophase of meiosis 1) to secondary
2) Secondary oocyte (arrested metaphase 2) to ovum
When does spermatogenesis begin?
Puberty
Germline epithelium of seminiferous tubules divide by mitosis
Draw flow diagram of spermatogenesis?
Where does meiosis occur
Outline process oogenesis
1) Oogonia
2) Primary oocytes (begin meiosis but arrested prophase 1)
3) Menstrual cycle begin- FSH trigger division primary oocytes
4) Secondary oocyte and polar body formed
5) Secondary oocyte begin second meiotic division arrested meta 2
6) Secondary oocyte released ovary (ovulation)- enter fallopian tube
7) Follicular cells surrounding the oocyte form a corona radiata and function to nourish the secondary oocyte
8) Fertilised sperm trigger the completion of meiosis II and the formation of another polar body (the first polar body may also undergo a second division to form a third polar body)
9) Once meiosis II is complete the mature egg forms a ovum
10) Fusing its nucleus with the sperm nucleus to form a zygote
What triggers division primary oocytes (to complete meiosis 1 in oogenesis)?
Beginning menstrual cycle (puberty)
FSH trigger division
What stage of meiosis are primary oocytes arrested in?
Prophase 1
What stage of meiosis are secondary oocytes arrested in?
Metaphase 2
What stimulates completion of meiosis 2 in oogenesis?
Ovulation- only completed at fertilisation
What is formed when egg fuses its nucleus with sperm nucleus?
Zygote
What is formed when egg fuses its nucleus with sperm nucleus?
Zygote
Draw flow diagram for oogenesis?
State when occurs
Meiosis
What is cell called that will differentiate into oogonium or spermatogonium?
Primordial germ cell
State meiotic division in oogenesis?
1) Prophase of meiosis 1- only mature in menstrual cycle
2) Metaphase of meiosis 2- only mature ovulation
- only complete fertilisation
