A 63-year-old patient

suffers from type II diabetes. After a long time, she goes for an eye

examination and is diagnosed with one of the frequent complications of

diabetes, the so-called diabetic retinopathy. Diabetic retinopathy develops

over several years before clinical manifestations appear, and thickening of the

basal lamina of endothelial cells is one of the signs of this disease during

the clinically silent period, which is caused by the excessive synthesis of

basal lamina components due to hyperglycemia. What layers does the basal lamina

consist of?