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. 2020 Oct 7;8:579925. doi: 10.3389/fbioe.2020.579925

FIGURE 2.

FIGURE 2

Ureter, urinary bladder, and penile urethra histological structure. Implantation of electrospun scaffolds in the urinary tract organs for reconstructive purposes through tissue engineering. (A) Schematic organization of ureter layers. The innermost layer, adjacent to the lumen, composed of specialized epithelium, urothelium, which protects the deeper layers from urine. The muscular layer of ureter is mostly composed of a longitudinally oriented inner layer and a circular outer layer. (B) Bladder histological organization. The inner transitional epithelium, urothelium, comprises 4–5 layers of highly specialized cells including umbrella cells at urine interface and basal cell adjacent to the basal lamina and submucosa. Bladder wall is mainly formed by a thick muscular layer (60–70% of normal bladder wall thickness) which is the major contributor of resilient nature of bladder wall. The bladder muscular layer is structurally organized as two outer longitudinal muscular layers intervened by circumferentially oriented muscular cells. (C) In the penile urethra the epithelium is mostly composed of pseudostratified columnar epithelium. The submucosa contains many venous spaces encompassed in connective tissue. (D) In ureter injuries, where end-to-end anastomosis is no possible, a tubular electrospun construct can be implanted to fill the injury and support the regeneration of ureter layers. (E) Augmentation cystoplasty is required for patients with diseased bladder that lost their functionality for being compliant and low-pressure reservoir. Electrospun scaffolds can provide a supportive matrix for regeneration of bladder tissue in partial augmentation cystoplasty. (F) Affected urethral wall with stricture lesion can be replaced by an electrospun scaffold through onlay or inlay fashion.