C22 - Urinary tract, blood supply and innervation

Question 1

Give the division of the urinary tract

Answer 1

• Upper urinary tract:
  
  • Pelvis renalis
  • Ureter
• Lower urinary tract:
  
  • Urinary bladder
  • Urethra
• In domestic mammals, the proximal ureter begins with a expansion of pelvis renalis, into which all the ductus papillaris open

Question 2

Histology of the urinary system

Answer 2

• Transitional epithelium (= urothelium) lines the organs of the urinary system
• Consists of several layers of epithelial cells which can contract and expand in order to adapt to the degree of distension needed

Question 3

Structures to mention

Answer 3

• Pelvis renalis
  
  • Recessus pelvis (ca)
  • Calices renalis (bo, su)
  • Recessus terminalis (eq)
• Ureter
  
  • ​Pars abdominalis
  • Pars pelvina
• Vesica urinaria
  
  • Apex vesicae [=Vertex vesicae]
  • Corpus vesicae
  • Cervix vesicae
  • Facies dorsalis
  • Facies ventralis
  • Lig. vesicae medianum
  • Lig. vesicae laterale
    
    • Lig. teres vesicae
  • Trigonum vesicae
  • Columna ureterica
  • Ostium ureteris
  • Plica ureterica
  • Ostium urethrae internum
• Urethra masculina​
  
  • Pars pelvina
  • Pars preprostatica
  • Pars prostatica
    
    • Crista urethralis
    • Colliculus seminalis
    • Ostium ejaculatorium
  • Pars penina
    
    • Recessus urethralis (su, Ru)
    • Processus urethrae (Ø su)
  • Ostium urethrae externum
• Urethra feminina
  
  • ​Ostium urethrae externum
  • Crista urethralis

Question 4

Pelvis renalis

Answer 4

• The proximal ureter begins with a expansion named pelvis renalis (ø bo)
• All the ductus papillaris open into pelvis renalis
• Pelvis renalis collects the urine, which reaches it through the papillary foramina, and conveys it into the ureter
• Location: within sinus renalis
  
  • ​But only fused with tissue around the papilla
• Pelvis renalis (ø bo)
  
  • ​Recessus pelvis (ca)
  • Calices renales (bo, su)
  • Recessus terminales (eq)
• Horse:
  
  • The renal pelvis consists of a central cavity and 2 recesuss terminales
  • ​Most of the ductus papillaris opens into recessus terminalis
• Carnivores:
  
  • Moulded around crista renalis
  • ​Extends ventrally and dorsally to form recessus pelvis
  • Separated by pseudopapillae and interlobular vesses
• Bovine:
  
  • Ø pelvis renalis
  • Calices renales formed by terminal branches of uteter
    
    • Uninte into 2 major channels, which converge from both poles of the kidney to form a single ureter
• Swine:
  
  • Calices renalis embrace an equal number of papilla renalis which protrude into pelvis renalis

Question 5

Ureter

Answer 5

• Extends from the pelvis renalis to the urinary bladder
  
  • ​Pelvis renalis → for. papilla → ureter
• Muscular tube
• Divided into:
  
  • Pars abdominalis
  • Pars pelvina
    
    • ​Enters the genital fold / lig. latum
• Enters the urinary ballder close to the cervix vesicae ostium urethris of the urinary bladder**​
• The ureter enters the bladder wall in such an angle, which automatically closes the way of urine backstream to the kidney from the filling bladder

​Innervation:

• Sympathetic and parasympathetic

Question 6

Urinary bladder

Answer 6

• Female: the bladder is related dorsally to uterus and lig. latum
• Male: short genital fold. The bladder is in contact with rectum, and are therefore more easily palpated rectally
• The surface of the bladder is covered with peritoneum (ø cervix vesicae)
• The bladder bladder muscle (m. detrusor) is arranged in 3 layers:
  
  • Outer longitudinal layer
  • Middle circular layer
  • Inner longitudinal layer
• M. sphincter vesicae:
  
  • ​Covers apex and cervix
  • Keeps the bladder closed
  • Smooth muscle
• Ureter:
  
  • Penetrates the muscular coat → producing two ridges (columna uretericae) on the inside → terminates at ostium urethris
  • ​Enters the bladder wall in such an angle, which automatically closes the way of urine backstream to the kidney from the filling bladder
• Trigonum vesicae:
  
  • Formed by:
    
    • 2 ostium ureteris
    • Ostium urethrae internum
  • The only fixed point of the bladder (no expansion)

Ligaments of the bladder:

• Lig. vesicae laterale
  
  • ​Peritoneal fold
  • Male: attached to dorsolateral wall
  • Female: attached to lig. latum
• Lig. teres vesicae
  
  • ​Cranial free edges of lig. vesicae laterale
  • Formed by a. umbilicalis
  • Originates from a. iliaca interna → apex vesicae
• Lig. vesicae medianum
  
  • ​Median fold
  • Between symphysis pelvis and linea alba → ventral surface of bladder

Structures:

• Apex vesicae (Blind cranial end)
• Corpus vesicae (Dorsal wall of the bladder does not form a fundus vesicae in domestic mammals)
• Cervix vesicae (Neck)
• Facies dorsalis
• Facies ventralis
• Lig. vesicae medianum (A peritoneal fold attaching the ventral surface of the bladder to the symphysis pelvina and linea alba)
• Lig. vesicae laterale (A peritoneal fold. Male: attached to dorsolateral pelvic wall. Female: attached to broad ligament)
  
  • Lig. teres vesicae (Remnant of a. umbilicalis)
• Trigonum vesicae (Smooth area of mucous membrane between the ostium ureteris and ostium urethrae internum)
• Columna ureterica (Elevation of the mucosa produced by the ureter in its course in the wall of the bladder)
• Ostium ureteris (Opening of the ureter)
• Plica ureterica (Lateral boundary of the trigonum vesicae)
• Ostium urethrae internum (Internal urethral orifice)

Question 7

Urethra feminina

Answer 7

• Beginsat cervix vesicae → caudal along the floor of the pelvis
• The uterine enters at the ostium urethrae internum and leaves through ostium urethrae externum
• Ostium urethrae externum (On the floor of the genital tract at the junction of the vagina and vestibule)
  
  • In vestibulum vaginae:
    
    • Ru, sus: divierticulum suburethrae
    • Ca: tuberculu urethrae
• Location:
  
  • Median in position
  • Dorsa: cagina (????)
  • Ventral: symphysis pelvis

Structures:

• Ostium urethrae externum
• Crista urethralis

Question 8

Urethra masculina

Answer 8

• Begins at the ostium urethra internum at the cervix vesicae
• Ends at the ostium urethrae externum at the tip of the penis
  
  • Ø su: processus urethralis ​

Structures:

• Pars pelvina (Begins at the internal opening at the cervix vesicae)
  
  • Pars preprostatica (Between bladder and prostata)
  • Pars prostatica
    
    • Crista urethralis (Dorsal ridge from the junction of the plica ureterica to colliculus seminalis)
    • Colliculus seminalis (Eminence on crista urethralis)
    • Ostium ejaculatorium (Opening of the ductus ejaculatiorius on the colliculus seminalis)
• Pars penina (Surrounds corpus spongiosum)
  
  • Recessus urethralis (su, Ru) (Opens ventrally into the urethra)
  • Processus urethrae (Ø su) (free distal part of the urethra)
• Ostium urethrae externum

Question 9

Blood supply

Answer 9

Ureter:

• A. renalis → r. utericus (to pars abdominalis)
• A. vaginalis/prostatica → r. utericus
• A. umbilicalis → r. utericus

Bladder:

• A. umbilicalis → a. vesicae cranialis (craniodorsal aspect)
• A. epigastrica caudalis → a. vesicae mediae (Ca, su????)
• A. vaginalis/prostatica → a. vesicae caudalis (to cervix vesicae, main blood supply)

Urethra:

• A. vaginalis/prostatica → r. urethralis
• A. pudenda interna → a. urethralis
• A. vesicalis caudalis → r. urethralis (to initial portion)
• The urethral wall contains venous plexus in submucosa (erectile properties)

Question 10

Innervation

Answer 10

• Autonomic fibers reaches the bladder through:
  
  • N. hypogastricus
    
    • ​Autonomus
    • From plexus mesentericus caudalis, runs to plexus pelvinus
    • Plexus vesicelis cranialis: with aa. vesicales cranialis in lig. vesice laterale to apex vesicae
    • Plexus vesicalis caudalis: to corpus vesicae and cervix vesicae
  • Nn. pelvini
    
    • ​From plexus pelvinus
• Sensory fibers goes through n. pudenda: to m. urethralis​
• Bladder:
  
  • N. hypogastricus
  • Nn. pelvini
• Urethra:
  
  • N. pudendus