It would be far more reassuring to students if medical information here was presented in correct English.
Take a look at the unnecessary apostrophe in the word 'cell's' on this page: http://www.livestrong.com/midget-bipolar-cells/. A quick grammar/spellcheck would have picked that up.
"midget bipolar cells medical dictionary
"Bipolar cell's in the inner nuclear layer of the retina that synapse with individual cone cell's in the outer plexiform layer; other larger bipolar cell's in the inner nuclear layer synapse with both rod and cone cell's; the axons of both types synapse in the inner plexiform layer with the dendrites of the ganglion cell's. "
English plurals do not take an apostrophe. The apostrophe signifies possession, or belonging, e.g. John's cat, teacher's pet, the cell's nucleus. If there were more than one teacher and pet, the apostrophe goes after the s, e.g. teachers' pets; if more than one cell and nucleus, that would become 'the cells' nuclei'. But the simple plural word 'cells', in the inner nuclear layer or anywhere, does not need an apostrophe.