Question

Discuss the internal struture of a testes?

Answer 1

Each testis is divided into many lobules by the fibrous
septa which project from the mediastinal testis into the
tunica albuginea. Each lobule is roughly conical in shape. Each lobule of the testes consists of:
Seminiferous tubular compartment
Interstitial compartment
SEMINIFEROUS TUBULAR COMPARTMENT
The seminiferous tubular compartment of each lobule of
the testis contains about 2–3 seminiferous tubules. The
seminiferous tubules constitute about 80–90% of the
testicular volume.
Each seminiferous tubule is about 80 cm long and 150 μm
in diameter. It consists of two parts: the convoluted part
and the straight part. The convoluted part forms the loops
and continues as two straight ends. Near the apex of the obules, the straight ends join one another to form 20–30
larger straight tubules (tubule recti). The straight tubules
pass through the fibrous tissue of mediastinal testis and
unite to form a network called rete testis. At the upper end
of each testis, the rete testis gives of 10–20 efferent ductules which continue into the head of epididymis.   

Spermatogenic cells
The spermatogenic cells lie in between the Sertoli cells.
These are arranged in an orderly manner in 4–8 layers,
which extend from the basal lamina to the lumen of the
seminiferous tubule.
  

Sertoli cells
Under electron microscope, each Sertoli cell appears as a
slender cell having irregular pyramidal shape. The base of
Sertoli cells rest on the basal lamina and each cell stretches from the basal lamina to the lumen of tubule.

INTERSTITIAL COMPARTMENT
The interstitial spaces between the seminiferous tubules
constitute about 10–20% volume of the testis. The inter-
stitial compartment of each lobule is filled by loose con-
nective tissue and Leydig cells. The Leydig cells or the
so-called interstitial cells are present in groups. They have
an endocrine function of secretion of male sex hormone
(testosterone)