Pars distalis stained to show the 3 major types of secretory epithelial cells there:
a = pale chromophobes
b = blue basophil
c = red acidophilNotice that these cells are characteristically in cord-like clumps. The clumps are separated by a fine reticular fiber stroma (thin blue lines), where the blood capillaries lie. All endocrine glands are highly vascularized, since secretions go directly into capillaries (depending on the organ.) In endocrine glands the endothelium of these vessel s is typically continuous and fenestrated.