Figure 3.

Layers that compose the bladder wall. The inner layer is called the urothelium, and its luminal surface is covered with glycosaminoglycan (GAG). The urothelium is composed of three sublayers. The first one is made of basal cells attached to a basement membrane; the superficial layers, i.e., the second and the third ones, are made of large hexagonal cells, the umbrella cells. Under the urothelium, the submucosa or lamina propria is composed of fibril-shaped or bundle-shaped collagens (type I and III), an elastin fibrous network, interstitial cells, fibroblasts, adipocytes, afferent and efferent endings, and blood vessels. Lastly, the outer layer is the muscular one (detrusor) covered by the adventitia. Created with BioRender.com, adapted from open access Wang et al., Pharmaceutics; published by MDPI, 2021 [12].