the surface density and area per cell of the endoplasmic reticulum ( er ) in periportal and perihepatic hepatocytes from male ddy mice , `` '' 17- , 18- , and 19-day-old fetuses , '' '' `` '' newborn and 1- , 5- , 10- , and 20-day-old animals , '' '' and `` '' adult animals '' '' were analyzed by quantitative electron microscopy .
C0007634
cell
C0014239
endoplasmic reticulum