UTWB Lesson 42: Basic Organs and Structures in the Abdominal and Pelvic Cavity part 2

What shaped lumen does the ureter have?

Star shaped

What type of epithelium lines the lumen of the ureter?

Transitional epithelium

What is the sub epithelial layer called?

Lamina propria 

What occurs in the lamina propria of the horse’s ureter?

Tubulo-alveolar mucus glands 

Horse ureter

A submucosa is lacking in the ureter, compared to the other organs of the urinary tract

What is the thickest layer of the ureter providing the major contractile forces?

Tunica muscularis

What is the outermost layer of the urethra?

The tunica adventitia or serosa 

Layer of loose connective tissue, nerves, blood vessels surrounding the muscularis layer 

Epithelial lining of the lumen in the urinary bladder type

Transitional epithelium

What is the epithelial lining of the urinary bladder called?

Mucosal lining or tunica mucosa

What does the submucosal layer of the urinary bladder contain? 

Contains elastic fibers and a layer of small bundles of discontinuous smooth muscle 

What is the tunica muscularis also referred to as?

Detrusor muscle

What is the detrusor muscle under control of?

Consists of smooth muscle fibers under control of the autonomic nervous system specifically the parasympathetic nervous system via the pelvic nerve

What is the outermost serous membrane lining of the bladder? 

Tunica adventitia or the tunica serosa 

Reduces friction and protects the bladder 

What is absent in the feline histology of the bladder?

The small bundles of smooth muscle which form a discontinuous lamina muscular of the submucosa are absent

What is the difference in urethra between males and females?

The female urethra is short, running from the bladder to the external urethral orifice

Tunica mucosa of the urethra

Folded longitudinally and the epithelium varies from transitional urothelium at the bladder to stratified columnar or cuboidal along the length, to stratified squamous at the urethral orifice in the tip of the penis 

What forms an erectile plexus in the lamina propria-submucosa of the urethra?

Endothelium-lined caverns/vascular spaces

Tunica muscularis of the urethra

Composed of smooth muscle in the vicinity of the urinary bladder and skeletal muscle in the remainder of the urethra

Tunica adventitia of the urethra 

Loose connective tissue furnished blood vessels and nerves, nerve endings are a constant feature 

Relationship between urinary and reproductive systems

Both located in the central midline of the abdominal and pelvic cavities

Reproductive organs dorsal or dorsolateral to the urethra

Where does the urethra open specifically?

The vestibulojunction (junction between the vagina and vestibule)

*Can be used to demarcate the 2 parts of the female genital tract

What must a surgeon be careful of when performing a spay?

Prevent the inclusion of the ureter when ligating and transecting the uterine body or when breaking down the broad ligaments 

Ductus deferens relationship to the ureter

Ductus deferens winds around the ureter

What is the genital fold?

Provides stability to the ductus deferens on the dorsal surface of the bladder 

Ectopic ureters

A congenital abnormality in which the ureteral orifices are located anywhere distal to the normal trigone location

The ureters may open into the bladder’s neck, urethra, vagina, or vestibule

What age and sex do ectopic ureters usually affect?

Usually affect young female dogs, median age = 10 months 

What are some clinical signs usually associated with the urinary system?

Urinary incontinence, stranguria, hematuria, pollakiuria

What are obstructions commonly due to?

Uroliths/calculi, infections, tumors

What sex is more anatomically predisposed to obstructions?

Males because their urethras are long and narrow 

What are common sites of blockage/urolith deposition?

Bladder, Ureter, Urethra

What are the 2 common sites of obstructions in ruminants?

Sigmoid flexure of the penis and urethral process

S-shaped sigmoid flexure

In ruminants and pigs, the body of the penis forms an s-shaped sigmoid flexure which allows for extension of the penis during erection 

Male urethra is also curved with a proximal and distal bend, urethra in the distal bend is narrower

Urethral diverticulum/recess

Found in male ruminants

The caudal end of the pelvic urethra forms a dorsal invagination or pouch at the ischial arch

Can become a nuisance when passing the catheter, sometimes gets stuck

Urethral sinus of the stallion

The urethra of the stallion ends as the cylindrical urethral process that is surrounded by a recess —> the fossa glands 

The fossa glandis has a dorsal diverticulum, the urethral sinus that may contain smegma 

What can happen over time in regards to the urethral sinus?

Over time the contents of the urethral sinus accumulate, harden, and become painful. The contents of the sinus are referred to as beans

What species are the sub-urethral diverticulum found in?

Female ruminants and the sow

What is the sub-urethral diverticulum?

The urethra forms a ventral evagination which opens together with the urethra into the vagina 

Point of obstruction when passing catheters to the bladder 

Cover the diverticulum with a finger when passing the catheter 

What species usually get lower urinary tract signs?

Dogs and cats, especially cats (feline lower urinary tract disease FLUTD)

What predispositions are there to lower urinary tract signs?

Breed, Sex

Male cats develop lower urinary tract obstructions more than females due to their narrow penile urethra

Spayed female cats develop a narrower pelvic urethra

What are some clinical signs associated with lower urinary tract signs?

Often anxious, may be aggressive or shy, bladder typically small and difficult to palpate, stranguria, may be large painful

What is the anatomical pathology of lower urinary tract signs?

Cystitis- redness and swelling of the bladder

Mucosal hyperplasia- calculi/plug in bladder or urethra

What is another name for the apex of the urinary bladder?

Vertex

What animals have a sub-urethral diverticulum? 

Cows and sows