Answer
The testes, or testicles, are the primary male sex organs. They function both as gonads and endocrine glands Each testis produces sperms and sex hormones. It is an ovoid structure that is composed of the following tissues:
The tunica vaginalis: this is a pouch of serous membrane of peritoneal origin
The tunica albuginea; this is the white fibrous capsule of the testis
The parenchyma is composed of seminiferous tubules-- these are ducts in which sperms are produced.
The parenchyma is divided into 200-300 wedge-shaped lobules and each lobule contains 1-3 seminiferous tubules.
Interstitial cells (Leydig cells) are the endocrine cells of the testes that secrete testosterone. They exist in clusters between the seminiferous tubules.
Blood Testis Barrier
There is a tissue barrier in the testes that prevents immunoglobulins and other large molecules in the blood and intercellular fluid from having access to the germinal cells. This barrier is formed by the tight junctions between sustentacular cells.It barrier prevents immunological attack of germ cells --which are different genetically from body cells-- by the body's immune system, with possible induction of sterility.
Work Step by Step
The germinal epithelium. This epithelium is composed of several layers of germ cells that develop into sperms through several stages.
Sustentacular cells (Sertoli). The sustentacular cells support the the germ cells in their important task of producing viable sperms. The Sertoli cells must provide adequate amounts of nutrients and growth factors and must remove the waste products and gases of germ cell metabolism. Sertoli cells also produce two important proteins-- androgen binding protein (ABP) and inhibin. These are important in the sperm production.
