Male reproductive system:
Internal male reproductive organs consist of
a) a pair of testis,
b) a pair of vasa deferens,
c) seminal vesicle
d) Ejaculatory duct
e) accessory glands i) mesogenic ii) ectodenia and
f) Genitalia
- Testis:
- Size is the same as the ovaries of Apterygota and very much smaller in Pterygota.
- They lie in the visceral cavity above the alimentary canal.
- Each testis consists of several oval-shaped structures known as follicles or sperm tubes.
- The entire follicle is covered by a peritoneal membrane whereas the testis is completely enveloped within a coat known as scrotum.
Structure of follicle
- The structure of the follicle is divided into 4 regions. i.e.
(i) Germarium: It is the region containing primordial germ cells or spermatogonia that undergo multiplication. (Zone of spermatogonia).
(ii) Zone of growth: It is the area where spermatogonia increase in size, undergo repeated mitosis, and develop into spermatocytes. (Zone of spermatocytes).
(iii) Zone of division and reduction: It is the area where spermatocytes undergo meiosis and give rise to spermatids (Zone of spermatids).
(iv) Zone of transformation: It is the area where spermatids get transformed inintopermatozoa. (Zone of spermatozoa).
- Vasa deferens: These are the long tubes formed by the union of vasa efferens which receive the sperms from the estis and allow their transport to the ejaculatory duct.
- Seminal vesicles: Each vas deferens becomes enlarged posteriorly to form a sac-like structure called a seminal vesicle for the storage of spermatozoa for some time.
- Ejaculatory duct: Both the vasa deferens of the two testes unite posteriorly to form a common median ejaculatory duct. The terminal section of the ejaculatory duct is enclosed in a finger-like evagination of the body wall, male copulatory organ, or aedeagus or penis.
- Accessory glands: These are 1-3 pairs & open the ejaculatory duct. In most cases, their secretion mixes with spermatozoa. These glands are called mushroom glands in cockroaches and mantids because of their appearance as mushrooms. This secretions facilitates sperm transmission from male to female.
