STRUCTURE OF SPERMATOZOA:Mature spermatozoa of a frog is made up of 3 parts i.e., head,middle piece and tail.Middle piece region is very small as compared to that of the other sperms,The head consists of acrosome and large nucleus. The acrosome secretes enzymes which helps in penetration into the egg. The middle piece of spermatozoon is composed of almost entirely of mitochondria and centriole(Centriole helps in the spindle formation during cleavage).The mitochondrial apparatus supplies the required amount of energy in the form of ATP.The tail of sperm is flagellar and very long.It helps in locomotion and thus is very essential for the mobility of the sperm.
2. Outer acrosomal membrane
4. Inner acrosomal membrane
6. Proximal centriole
7. Rest of the distal centriole
8. Thick outer longitudinal fibers
12 . Ring fibers
D. Principal piece