Biology today

• after their maturation, spermatozoa detach from Sertoli cells.
The process is called spermiation. The released sperms are
stored in epididymis and first portion of vasa deferentia
for upto one month. here they gain motility. Nutrition is
provided by epithelium of epididymis.

sperm or spermatozoon

• Sperm is a microscopic structure composed of a head, neck,
a middle piece and a tail. a plasma membrane envelops the
whole body of sperm.

• The sperm head contains an elongated haploid nucleus,
the anterior portion of which is covered by a cap-like
structure, acrosome. It is derived from Golgi complex of
the spermatid. acrosome contains proteolytic and lysosomal
enzymes popularly called sperm lysins, e.g., hyaluronidase,
proteases, acid phosphatase. The surface of head contains
adhesions (decapacitation factors) which have to be removed
before it becomes capable of fertilising an ovum.

• The middle piece possesses numerous mitochondria, which
produce energy for the movement of tail that facilitate sperm
motility essential for fertilisation.

Acrosome

Plasma membrane

Post acrosomal sheath

Distal centriole

Proximal

centriole

Mitochon-

drial spiral

Axial

filament

(9 + 2

fibrils)

Fibrous sheath

Tail

Annulus

Middle piece

Neck

Head Nucleus

End piece

Fig.:A mammalian spermatozoon

It is enlargement of testicle due to accumulation of fluid

usually in tunica vaginalis.

This is the enlargement of the prostate gland. It

compresses the urethra, causing frequent night

urination (nocturia) or difficult or painful micturition.

It is a failure of one or both of the testicles to descend into the

scrotum. Cryptorchidism is caused by deficient secretion of

testosterone by foetal testes.I f spontaneous descent does

not occur by the age of one year, hormonal injection is given.

Retention of testes in the abdomen results in sterility.

Cryptorchidism

Sperms are unable to fertilise the ovum due to

low count or less motility.

Sterility

It is the inability of the adult male to achieve penile

erection. It can be due to physiological, psychological

or neuromuscular defects.

Impotence

It is cancer of prostate. Some symptoms are dysuria, difficulty in

voiding, increased frequency of urination or urinary retention.

Prostate carcinoma

Inguinal hernia

Hydrocoele

It is inflammation of prostate generally caused by infection.

Prostatitis results in perineal or testicular discomfort, mild

dysuria and symptoms of urinary obstruction.

Prostatitis

Disorders of male

reproductive system

Benign prostatic hypertrophy (BPH)

Tearing of inguinal tissue may result in protrusion ofapart of

intestine into scrotum.

1. Explain how blood-testis barrier provides a protective environment for sperm development?


2. Levels of testosterone regulate functioning of male reproductive system. Justify.


3. What is spermiogenesis and how does it take place?