Paired fibromuscular tubes that transport urine from the renal pelvis to the urinary bladder
Ureters
Abdominal part
Pelvic part
How does the ureterpenetrates the bladderwall?
The ureter penetrates the bladder wall obliquely
Intramural ureter
Part of the ureter which lies within the bladder from its point of entry in the wall to the orifice in the trigone
How does the ureter empties into urinary bladder?
Each ureterempties into the urinarybladder by a slit opening (urethralorifices) at the cranialmargin of the neck
Ureters in cattle
The ureter divides into two branches directed toward the cranial and caudal poles of the kidneys
The primary branches of the ureter subdivide to form 18-22 secondary branches each of which carrying a calix
Lower urinary tract
Consists of urinary bladder, caudal ureter, and urethra
Urinary bladder
Apex: cranial blind end
Body: region situated between the neck and apex
Neck: funnel-shaped region between ureteric orifice and urethra
Bladder trigone
Triangular region of the internal urinary bladder formed by the two ureteric orifices and the internal urethral orifice
Anatomical location of urinary bladder
In carnivores, the bladder extends into the abdominal cavity
In large animals, the bladder confined to the pelvic cavity
When the bladder enlarges and filled with urine, it becomes pear-shaped
As the pressure rises (create the urge to void urine), tension in the bladder wall acts to CLOSE the intramural ureter and preclude urine reflux
Detrusor muscle
Smooth muscle coat of the bladder apex and body, expels urine
Smooth muscle sphincter
Muscle coat of the bladder neck & cranial urethra (internal urethral sphincter), regulates involuntary control of urine flow from the bladder to the urethra
External urethral sphincter
Striated urethralis muscle entirely replaces smooth muscle in the distal third of the urethra, provides voluntary control of urine flow from the bladder to the urethra
Blood supply of urinary bladder
Receives main blood supply from the caudal vesical arteries, which are branches of the prostatic (male) or vaginal (female) arteries
Supplemented cranially by the umbilical arteries
Innervation of urinary bladder
Receives sympathetic and parasympathetic innervation (autonomic nervous system-motor division)
Sympathetic fibers arise from the hypogastric nerves
Parasympathetic pelvic nerves are derived from the pelvic nerves
When the bladder is full
There are sensory nerves conveying this information to the brain to increases parasympathetic tone and decreases sympathetic activity
Sympathetic influence on the internal urethral sphincter
Becomes suppressed so that the internal sphincter relaxes and opens
Urethra
Tubular organ that serves as an outlet for urine from the urinary bladder
Female urethra
Continuous with the bladder, runs caudally on the pelvic floor ventral to the reproductive tract
Passes obliquely through the vaginal wall and opens with the external urethral opening ventrally at the junction between vagina and vestibule
Male urethra
Consists of pelvicpart (preprostatic portion and prostatic portion) and penile part
Preprostatic portion is short, extends from the internal opening of the urethra to the seminalhillock
Prostatic portion is the portion that passes through the prostate gland
Males are at greater risk of obstructive FLUTD due to their narrower urethra
Cats with FLUTD most often show signs of difficulty and pain when urinating, increased frequency of urination, and blood in the urine
In cattle, the ureter is formed by the short passages that lead from renal calyx
Muscular part of the bladder
Detrusor muscle: smooth muscle coat of the bladder apex and body, expels urine
Smooth muscle sphincter: muscle coat of the bladder neck & cranial urethra (internal urethral sphincter)
Internal urethral sphincter
Regulates involuntary control of urine flow from the bladder to the urethra
Sympathetic nerves
Directly cause relaxation and expansion of the detrusor muscle, promoting urine filling
Parasympathetic nerves
Control bladder contractions and the passage of urine
Urethral sphincters
Internal urethral sphincter: smooth muscle continuous with the detrusor muscle, regulates involuntary control of urine flow
External urethral sphincter: striated urethralis muscle, provides voluntary control of urine flow
Urinary or urethral incontinence is the loss of voluntary control of urination, usually observed as involuntary urine leakage
FLUTD (feline lower urinary tract disease) is a general term used to describe conditions affecting the bladder or urethra of cats, including physical conditions and behavioral disorders resulting in inappropriate urination
The two most common types of bladderstones in cats are struvite stones and calcium oxalate stones
How does the ureter penetrates the bladder wall
The ureter penetrates the bladder wall obliquely.
How does the ureter empties into urinary bladder?
Ureter empties into UB by a slit opening (urethral orifices) at cranial margin of neck
Struvite stones
The most common type of bladder stone in cats; made up of magnesium, ammonium, and phosphate; can form in cats with a high urine pH
Calcium oxalate stones
The second most common type of bladder stone in cats; made up of calcium and oxalate; can form in cats with a low urine pH
Sympathetic influence on the internal urethral sphincter
Relaxes and opens the internal urethral sphincter, allowing urine to flow
Intramural ureter
Part of the ureter located within the bladder wall
Urine reflux
Backward flow of urine from the bladder into the ureter and potentially back up into the kidney