Fenestrations are seen in:
Ans: a (Endothelium) Ref: Ganong, 22nd ed, p. 578In most endocrine glands, intestinal villi and parts of kidneys the cytoplasm of the endothelial cells is attenuated to form gaps called "fenestrations". They are usually 20 -100 nm in diameter. They permit passage of relatively large molecules and make the capillaries porous. They usually appear closed by a thin membrane.Exceptions: Kidney glomemli, liver not closed by a thin membrane. In hepatic sinusoidal capillaries the pores may be as large as 3000 nm.Lymphatics Vs Capillaries (diffuse histology)
Endothelium
Internal elastic lamina
External elastic lamina
Tunica media
Heart, Circulation, and Blood