Spermatogenesis and Oogenesis PDF

Chapter 2 Spermatogenesis and Oogenesis HIGHLIGHTS A spermatozoon has a head, a neck, a middle piece and a principal piece or tail (Fig, 2.1). Stages of spermatogenesis are summarized in Fig. 2.5. S p e r m a t o z o a are derived from r o u n d e d spermati...

Chapter 2 Spermatogenesis and Oogenesis HIGHLIGHTS A spermatozoon has a head, a neck, a middle piece and a principal piece or tail (Fig, 2.1). Stages of spermatogenesis are summarized in Fig. 2.5. S p e r m a t o z o a are derived from r o u n d e d spermatids. The process of conversion of a s p e r m a t i d to a s p e r m a t o z o o n is called spermiogenesis {Fig.2.6). Stages of oogenesis are s u m m a r i z e d in Fig. 2.8. An ovarian follicle is a rounded structure that contains a developing ovum surrounded by follicular cells. The follicle has a fluid filled cavity (Fig. 2.12). O v a r i a n follicles have a cellular covering called the theca interna. The cells of the theea In this chapter we shall first study the structure of interna produce oestrogens (Fig. 2.13). a m a t u r e spermatozoon {male sex cell) before considering its formation in the testis. The follicle gradually increases in size and finally bursts to expel the ovum. This process of shedding of the ovum is called ovulation. STRUCTURE OF A MATURE SPERMATOZOON The corpus luteum is formed by enlargement and transformation of follicular cells, after A spermatozoon is a highly specialized, free swim- shedding of the ovum {Fig. 2.17), The corpus ming, actively motile cell. The spermatozoon has luteum secretes progesterone, which is essential a head, a neck, a middle piece and a principal piece for maintenance of pregnancy. or to'/(Fig. 2.1). An axial filament passes through the middle piece and extends into the tail. The spermatozoon measures about 60 um in length. The Head The head of the human spermatozoon is piriform in shape and measures 4 urn in length. It is derived Chapter 2 Spermatogenesis and Oogenesis HIGHLIGHTS A spermatozoon has a head, a neck, a middle piece and a principal piece or tail (Fig. 2.1). Stages of spermatogenesis are summarized in Fig. 2.5. S p e r m a t o z o a are derived from r o u n d e d spermatids. The process of conversion of a s p e r m a t i d to a s p e r m a t o z o o n is called spermiogettesis (Fig.2.6). Stages of oogenesis are s u m m a r i z e d in Fig. 2.8. An ovarian follicle is a rounded structure that contains a developing ovum surrounded hy follicular cells. The follicle has a fluid filled cavity (Fig. 2.12). O v a r i a n follicles have a cellular covering called the theca interna. The cells of the theca In this chapter we shall first study the structure of interna produce oestrogens (Fig. 2.13). a mature spermatozoon (male sex cell) before considering its formation in the testis. The follicle gradually increases in size and finally bursts to expel the ovum. This process of shedding of the ovum is called ovulation. STRUCTURE OF A MATURE SPERMATOZOON The corpus Iuteum is formed by enlargement and transformation of follicular cells, after A spermatozoon is a highly specialized, free swim- shedding of the ovum (Fig. 2.17). The corpus ming, actively motile cell. The spermatozoon has Iuteum secretes progesterone, which is essential a bead, a neck, a middle piece and a principal piece for maintenance of pregnancy. or tot/(Fig. 2.1}. An axial filament passes through the middle piece and extends into the tail. The spermatozoon measures about 60 urn in length. The Head The head of the human spermatozoon is piriform in shape and measures 4 pm in length. It is derived  Spermatogenesis and Oogenesis Coarce petal " >! » / -...*'. A v >? **. ^\. Fibrous sheath ;».?.'.'«.#:T't.\»-.'«V^4-- >... ' °°-6 ^ : : ! i.' % #.;:;....:. :. - ?»