Scanning Electron Microscopy of Vascular Casts For the Study of Vessel Connections in a Complex Vascular Bed - The Trout Gill

The microcirculation of fish gills has been investigated by light microscopic study of sample or serial sections, transmission electronmicroscopy, and microscopic study of intact Blood or ink filled gill filaments; it is considered to consist of a series of respiratory pathways and non-respiratory shunts. However, reconstruction of a complex 3 dimensional structure from 2. dimensional information, as is available from section study, is fraught with difficulty, especially in establishing connections between micro-vessels. Also, investigation of intact specimens is hampered by poor resolution and inadequate depth perception into the tissue. Perfusion of the microcirculation with a liquid plastic mixture which will polymerise in situ produces a mechanically selfsupporting object, after tissue removal, for study with the S.E.M; this approach permits direct examination of the microvasculature in three dimensions.