Trigone of urinary bladder
Urinary bladder
The interior of bladder.
Latin	trigonum vesicae urinariae
Gray's	subject #255 1231

The trigone is a smooth triangular region of the internal urinary bladder formed by the two ureteral orifices and the internal urethral orifice.

The area is very sensitive to expansion and once stretched to a certain degree, the urinary bladder signals the brain of its need to empty. The signals become stronger as the bladder continues to fill.

Embryologically, the trigone of the Bladder is derived from the caudal end of mesonephric ducts. In the Female the mesonephric ducts break down but, thus, the Trigone of the Bladder is less prominent but, still present.

Contents 1 Pathology 2 Additional images 3 See also 4 External links

[edit] Pathology

Clinically important because infections (trigonitis) tend to persist in this region.

[edit] Additional images

[edit] See also

• Trigonitis

[edit] External links

• trigone+of+bladder at eMedicine Dictionary
• SUNY Labs 44:04-0203 - "The Male Pelvis: The Urinary Bladder"

v • d • e Anatomy: urinary system (TA A08, GA 11.1215) Abdomen Kidneys Layers Renal fascia • Renal capsule • Renal cortex  (Renal column) • Renal medulla (Renal sinus, Renal pyramids, medullary interstitium) • Renal lobe • Cortical lobule • Medullary ray • Nephron Afferent circulation Renal artery → Segmental arteries → Interlobar arteries → Arcuate arteries → Interlobular arteries → Afferent arterioles → Renal corpuscle (Glomerulus, Bowman's capsule) Renal tubule Proximal tubule → Loop of Henle (Descending, Thin ascending, Thick ascending) → Distal convoluted tubule → Connecting tubule → Collecting ducts aka Duct of Belini → Renal papilla → Minor calyx → Major calyx → Renal pelvis Efferent circulation Glomerulus → Efferent arterioles → Peritubular capillaries / Vasa recta → Arcuate vein → Interlobar veins → Renal vein Juxtaglomerular apparatus Macula densa • Juxtaglomerular cells • Mesangium/Extraglomerular mesangial cell Filtration Glomerular basement membrane • Podocyte • Filtration slits • Mesangium/Intraglomerular mesangial cell • Tubular fluid Ureters Orifice of ureter Pelvis Bladder Uvula • Trigone • Detrusor • Apex • Neck Urethra Urethral sphincters (External sphincter muscle of male urethra, External sphincter muscle of female urethra, Internal sphincter muscle of urethra) urinary system navs: anat/physio/dev, noncongen/acid+base/congen/neoplasia, symptoms+signs/eponymous, proc

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