Adrenal Cortex - Zona fasciculata
Zona fasciculata lies between zona glomerulosa (beneath capsule) and zona reticularis (deep). It makes up about 75% of the thickness of the cortex. Abundant lipid content of fasciculata cells is responsible for yellow color of cortex grossly. Dissolution of lipid during specimen processing gives cytoplasm a clear spongy appearance as seen here. Zona fasciculata is responsible for synthesizing glucocorticoids as wells adrenal androgens. Ultrastructurally, the main features of zona fasciculata cells are abundant smooth endoplasmic reticulum, tubulovesicular mitochondria, and numerous lipid droplets.