. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 320 P. R. SMITH ET AL. •> = >',3 be ''"• >>^^H^--A - -. FIGURE 3. TEMs of nephridium and nephridioduct of mitraria larva ofOweniafusiformis. A. Trans- verse section through distal most portion of nephridium near point of union with nephridioduct. Note lysosome-like bodies (ly) within cytoplasm of podocytes. Scale = 1 jum. B. Transverse section through medial portion of nephridioduct. Note adhaerens junction (arrow) between apposed surfaces of doughnut- shaped cell and numerous endocytotic vesicles (arrowh
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 320 P. R. SMITH ET AL. •> = >',3 be ''"• >>^^H^--A - -. FIGURE 3. TEMs of nephridium and nephridioduct of mitraria larva ofOweniafusiformis. A. Trans- verse section through distal most portion of nephridium near point of union with nephridioduct. Note lysosome-like bodies (ly) within cytoplasm of podocytes. Scale = 1 jum. B. Transverse section through medial portion of nephridioduct. Note adhaerens junction (arrow) between apposed surfaces of doughnut- shaped cell and numerous endocytotic vesicles (arrowheads) within its cytoplasm. Cilia (ci) situated within its lumen extend from duct cells. Scale = C. Ciliary basal body (bb), rootlet (it), and accessory centriole (ac) of a nephridioduct cell. Note microvilli (mv) within duct lumen and endocytotic vesicles (arrowheads) within cytoplasm of duct cell. Arrow indicates direction of nephridiopore. Scale = ^m. D. Parasagittal section through distal most portion of nephridioduct. Note endocytotic vesicles (arrowheads) within duct cell cytoplasm. Arrow indicates direction of nephridiopore. Scale = 1 ac, acessory centri- ole; bb, basal body, be, blastocoel; ci, cilia; ecm, basal extracellular matrix; in, intestine; lu, lumen of nephridioduct; ly, lysosome-like body; mv, microvilli; po, podocyte; rt, rootlet. (Ruppert and Smith, 1985; in prep.). Based on these definitions, each mitraria ne- phridium is a giant protonephridium. Presumably the ECM between the podocyte pedicels forms the filtration surface while the podocyte and duct cilia produce the filtration pressure gradient. Blastocoelic fluid may be ultrafiltered across the ECM between the pedicels. Numerous endocytotic vesicles in the podocyte perikarya sug- gest that modification of the ultrafiltrate occurs within the nephridium. Additional. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabili
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
