Structure of a *** ( Spermatozoa)**
(i) It consists of four parts: head, neck, middle piece and tail.
(ii) Head: It is the enlarged end of a *****, containing the large haploid nucleus, i.e., condensed chromatin body and is capped by acrosome, the acrosome contains hydrolytic enzymes that help in dissolving membranes of the ovum for fertilisation.
(iii) Neck: It contains proximal centriole towards the nucleus which is necessary for the first cleavage division of zygote and the distal centriole that is connected to the tail filament.
(iv) Middle piece: It contains a number of mitochondria that provide energy for the movement of the tail that facilitate ***** motility essential for fertilisation.
(v) Tail: It consists of an axial filament surrounded by the plasma membrane. It helps the sperms to swim in a fluid medium.
(vi) A human male ejaculates about 200-300 million sperms during a **. Seminal plasma along with the sperms constitute the *****.
