Ureteral structure and ultrastructure. Part I. The normal human ureter

Area of Science:

• Anatomy and Histology of the Human Ureter
• Urothelial Ultrastructure and Innervation

Background:

• The human ureter's complex muscular structure and cellular organization remain incompletely understood.
• Detailed ultrastructural analysis is crucial for understanding ureteral function and potential pathologies.

Purpose of the Study:

• To elucidate the microanatomy and ultrastructure of normal human ureters.
• To identify potential pacemaker cells and assess muscle cell contractility.
• To briefly describe urothelial ultrastructure and ureteral nerve components.

Main Methods:

• Light and electron microscopy of 28 normal human ureters.
• Microdissection of three uretero-trigonal units.
• In vitro assessment of muscle cell contractility.

Main Results:

• The ureter is a non-layered muscular tube composed of heterogeneously oriented muscle bundles.
• Nexus structures provide functional continuity between muscle cells.
• Distinct muscle cells identified as potential ureteral pacemaker cells; contractility is feasible in vitro.

Conclusions:

• The human ureter exhibits a unique muscular organization with identifiable pacemaker cells.
• Morphological changes correlate with muscle cell functional status (contraction/relaxation).
• Provides foundational ultrastructural data on normal ureter anatomy and innervation.