A scanning electron microscopy study of human spleen: relationship between the microcirculation and functions

Area of Science:

• Anatomy
• Microcirculation
• Immunology

Background:

• The human spleen's complex vascular architecture is crucial for its immune and filtration functions.
• Previous studies have provided limited insights into the precise terminal patterns of splenic arteries.

Purpose of the Study:

• To detail the arterial supply and terminal structures within the human spleen using advanced imaging techniques.
• To elucidate the functional implications of different arterial terminal modes in the spleen.

Main Methods:

• Utilizing scanning electron microscopy (SEM) for detailed observation.
• Employing freeze-cracked surfaces and vascular casts of the human spleen to visualize the microvasculature.

Main Results:

• Identified three distinct modes of arterial terminals in the human spleen: openings in the marginal zone, openings into the cords of Billroth, and direct connections with sinuses.
• Described the pathways of central arteries, penicillar arteries, and follicular arteries, including unique structures like "arteriolar-capillary bundles" and labyrinthine arterial channels.
• Demonstrated that arterial openings in the marginal zone may be involved in antigen presentation, cordal openings in blood cell processing, and sinus connections in rapid blood flow.

Conclusions:

• The human spleen possesses a versatile arterial system with multiple terminal configurations supporting diverse physiological functions.
• SEM analysis of freeze-cracked surfaces and vascular casts provides critical anatomical detail for understanding splenic hemodynamics and immune interactions.
• These findings enhance our comprehension of splenic circulatory dynamics and their roles in immune surveillance and hematological filtration.