The document summarizes the structure of sperm. It describes that sperm has a head, neck, middle piece, and tail. The head contains the acrosome and nucleus. The acrosome secretes enzymes that help the sperm penetrate the egg. The neck contains two centrioles that form the sperm's tail and spindle during fertilization. The middle piece is cylindrical and contains mitochondria spiraled around axial filaments. The tail is made of principal and end pieces, with the principal piece containing all filaments and the end piece only containing the central filaments.

1. STRUCTURE
OF
SPERM

2. PARTS OF A SPERM
 Head
 Neck
 Middle Piece
 Tail
 Principal piece
 End piece

3. HEAD OF SPERM
In man it is flat, oval and spoon
shaped.
ACROSOME forms its tip covered
by a doubled walled membrane
extending down along nucleus to
form the head cap.
Acrosome secrete an enzyme
SPERM LYSINE / HYALURONIDASE.

4. HEAD OF SPERM cont…
SPERM LYSINE / HYALURONIDASE
help penetration of sperm into
ovum.
NUCLEUS with a compact mass of
DNA, occupies major part of head
below acrosome.

5. NECK OF SPERM
It is small constricted portion
between head and middle piece.
It has two centrioles perpendicular
to each other.
PROXIMAL CENTRIOLE is donated
to ovum to form spindle during
division.
DISTAL CENTRIOLE behind gives
axial filaments to form tail.

6. MIDDLE PIECE OF SPERM
 It is cylindrical with AXIAL FILAMENTS at
centre it has two central surrounded by
nine doublets.
 Mitochondria are SPIRALLY coiled
around axial filaments and are compact.
 Entire is surrounded by a thin layer of
cytoplasm called MANCHETTE below
plasmalemma.
 At end has a dark RING CENTRIOLE of
unknown function.

7. TAIL OF SPERM
First part is main piece and last is
end piece.
Main piece has all filaments
surrounded by a fibrous sheath but
end piece has only central two
axial filaments.
Entire is surrounded by a very thin
film of cytoplasm and
plasmalemma.