Male Reproductive System Anatomy

Testis Structure and Function

• The average diameter of seminiferous tubules in the testis is 150-300 μm.
• Leydig cells secrete androgens in the testis.
• Sertoli cells physically and metabolically support developing sperm precursors in the testis.

Sperm Movement and Development

• Myoid cells in the testis contribute to sperm movement by contracting and relaxing to facilitate sperm transport.
• Sperm travels from the rete testis to the epididymis in the testis anatomy.

Leydig Cells

• The main function of Leydig cells in the testes is to produce androgens, primarily testosterone.
• The secretion of testosterone by Leydig cells is triggered by luteinizing hormone (LH).
• Smooth endoplasmic reticulum and mitochondria are involved in the synthesis of testosterone in Leydig cells.
• Leydig cells begin synthesizing testosterone during fetal development.
• During late pregnancy, fetal interstitial cells differentiate into Leydig cells.

Pampiniform Plexus and Dartos Muscle

• The primary function of the pampiniform plexus surrounding the testicular artery is to regulate testicular temperature.
• The dartos muscle plays a role in maintaining testicular temperature by contracting and relaxing to adjust scrotal skin.

Testicular Anatomy

• The tunica vaginalis is responsible for covering the anterior and lateral sides of the testes.
• The failure of the testes to descend into the scrotum is known as cryptorchidism.

Epididymis and Sperm Maturation

• The role of the epididymis in the male reproductive system is to store, mature, and transport sperm.
• The duct of epididymis is lined with pseudostratified epithelium.
• Principal cells in the epididymis are involved in the transport of sperm and the absorption of excess fluids.
• The ductus deferens is continuous with the duct of epididymis during ejaculation.
• Sperm cells undergo further modifications in the corpus epididymis.

Efferent Ductules and Rete Testis

• The efferent ductules are initially lined by ciliated cuboidal cells.
• The main function of non-ciliated cuboidal cells in the efferent ductules is to absorb excess fluids.
• The efferent ductules closer to their connection to the duct of epididymis are lined with simple cuboidal epithelium.
• The rete testis is composed of interconnected channels lined with simple cuboidal epithelium.
• Circular smooth muscle cells in the walls of the efferent ductules help regulate fluid flow.

Sperm Quality and Spermatogenesis

• A common feature of low sperm quality is abnormal sperm morphology.
• Spermatogonia are located near the basal lamina of the seminiferous tubules.

Sertoli Cells and Blood-Testis Barrier

• The blood-testis barrier in the seminiferous epithelium is formed by tight occluding junctions between basolateral Sertoli cell membranes.
• Sertoli cells' extended surfaces are involved in phagocytosis and nutrient transport to support spermatogenic cells.
• The main role of Sertoli cells within the seminiferous tubules is to support and nurture developing sperm cells.
• Tight occluding junctions between basolateral Sertoli cell membranes are significant for maintaining the immunological barrier.
• Abundant lysosomes in Sertoli cells are involved in various cellular processes.
• Sertoli cells have characteristic tripartite nuclei.
• A key metabolic function of Sertoli cells in supporting germ cells is to provide lactate and other nutrients.