Distinguish between spermatogenesis and oogenesis.
Spermatogenesis
It occurs inside testis
All stages are completed inside testis.
It is a continuous process.
Spermatogonia develop from germinal epithelium lining the seminiferous tubules.
Some cells of the germinal epithelium function as support , also called sertoli cells.
All the spermatogonia divide to form spermatocytes.
Growth phase is short.
Primary spermatocyte divides by meiosis I to form two secondary spermatocytes.
Secondary spermatocyte divides by meiosis II to produce two spermatids.
A spermatocyte forms four spermatozoa.
Sperms are smaller than spermatocytes.
Nucleus undergoes condensation in the *****.
Reserve food is little in the sperms.
14.It produces motile male gametes.
Oogenesis
It occurs inside ovary.
Major part of oogenesis occurs inside ovary but last stages occur inside oviduct.
It is discontinuous process with early stages taking place in foetus and the rest later in life.
Oogonia develop from germinal epithelium overlying the ovary.
There is no such differentiation.
Only some oogoinia give rise to oocytes.
Growth phase is prolonged.
Primary oocyte undergoes meiosis I to form one secondary oocyte and one polar body
Secondary oocyte divides by meiosis II to form one ovum and one polar body.
A oocyte forms only one egg or ovum.
Eggs are larger than oocytes.
Nucleus *** uncondensed in the ovum.
Ovum collects a lot of reserve food and other biochemicals.
It forms non motile female gametes.
