ANATOMY

Detailed explanation-1: -This is the structure of the nephron that filters blood. This lies in the anterior corner of the trigone of the bladder. This term means the return of substances into the blood stream from the filtrate.

Detailed explanation-2: -The corners of the trigone are formed by three orifices: the paired ureteral orifices and the internal urethral orifice.

Detailed explanation-3: -Definition. The internal urethral orifice is placed at the apex of the trigonum vesicæ, in the most dependent part of the bladder, and is usually somewhat crescentic in form; the mucous membrane immediately behind it presents a slight elevation, the uvula vesicæ, caused by the middle lobe of the prostate.

Detailed explanation-4: -The internal urethral sphincter is located inferiorly, in the neck of the bladder. In males, the inferior vesical artery supplies blood to the neck and fundus of the bladder.

Detailed explanation-5: -The trigone is formed predominantly from bladder muscle. Histological studies suggest that two muscle groups reside in the trigonal region: the detrusor muscle of the bladder and longitudinal ureteral fibers.