Veterinary Anatomy of Urinary system and specie difference between different species

Veterinary Anatomy of Urinary system and specie difference between different species

1. Urinary System

2. Learning Outcomes
•Enlist organs of urinary system
•Describe structure, blood supply, lymphatic
drainage, innervation, and location of urinary
organs
•Describe species differences of urinary organs
•Draw labelled diagrams of urinary organs and
their relations with adjacent organs

3. •Kidneys (Location, shape, structure, functional
unit, blood supply, lymphatics, innervation)
•Renal Pelvis
•Ureters (Location/course)
•Urinary bladder (Location, structure, relations,
BS, L, Inn)
•Urethra (Location, structure, BS, L, Inn)


Organs of Urinary System

4. Kidneys (nephros, ren)
•Location
–Retroperitoneal, embedded in fat
–Pressed against vertebral column dorsally
–Lumbar region, extending into ITA (Exact position??)
–Right kidney more cranial in position, in the renal fossa
of liver
–Left kidney more mobile
–In ruminants, left kidney pushed into right half of
abdomen by rumen

11. Kidney - Shape & Appearance
–Reddish-brown, smooth-surfaced (except Ox)
–Basic form is bean-shaped (Dog, Cat, Sheep & Goat)
–Right kidney of horse has a valentine heart shape
–Left kidney of horse has a bean to pyramidal shape
–Bovine kidney is irregular oval shape, superficially
fissured into lobes

12. Kidney - Shape and Appearance
–Dorsal and Ventral Surfaces (Relations ??)
–Lateral and Medial Borders (Relations ??)
–Cranial and Caudal Extremities
–Renal Hilus (indented medial border for passage of
renal pelvis, vessels, and nerves)
–Renal Sinus, fat filled space around renal pelvis

13. Kidney - Structure
–Fibrous capsule (can be easily removed from
healthy kidney)
–Parenchyma divided into
•Outer renal cortex (reddish-brown, granular)
•Inner renal medulla (dark outer and pale inner zone)
–All mammals have lobulated kidney during
embryonic life, these lobes fuse variably in
different animals

14. Kidney - Structure
–OX
•Cortex and medulla divided into
pyramid shaped lobes
•Apex of each lobe forms a papilla
and fits into cup shaped
expansion (calyx) of renal sinus
•In Ox, lobes are superficially
visible

15. Kidney - Structure
Dog, Horse, Sheep
–Lobes fuse to form a single
medullary mass with
continuous cortical shell
–Papilla fuse to form a single
renal crest

16. Kidney
Based on degree of fusion
•Unilobar kidney with smooth surface and single
papillla – dog, cat, horse, small ruminants
•Multilobar kidneys with a lobated surface and
multiple papillae - Ox

17. Kidneys of Dog/Cat/Horse/Small Ruminants

Smooth surface / fused cortex
Fused medullary lobes
Renal Pelvis
Renal Sinus

18. Kidney of OX

Multilobar/fissured surface
Unfused medullary lobes
Renal papillae

19. Kidney – Functional Unit
• Nephron / Renal tubules
•Their number varies among the different
domestic mammals.
–up to 400 000 nephrons in the kidney of a dog
–500 000 in a cat
–I Million in a pig
–4 Million in an ox
–up to 2.7 Million in a horse.

20. •Each nephron is made up of
–Glomerular capsule
–Proximal convoluted tubule
–Loop of Henle
•Descending limb
•V-turn
•Ascending limb
–Distal convoluted tubule

Kidney – Functional Unit

21. Distal convoluted tubule 
Straight collecting tubule 
Papillary Duct 
Renal Pelvis at cribriform
areas

Cribriform areas are
confined to the
•apices of independent
papillae (ox and pig)
•specific regions of a
common crest (cat, dog,
small ruminants, horse).

22. Abdominal aorta
Renal artery
Interlobar artery
Arcuate artery
Interlobular artery
Afferent glomerular artery
Glomerulus
Efferent glomerular artery
Capsular branch
Capillary plexus
Interlobular vein
Arcuate vein
Interlobar vein
Renal vein
Caudal vena cava
Kidney – Blood Supply

24. Kidney: Lymphatics and Innervation
•Lymphatics terminate in renal lymph nodes
•Innervation
–Sympathetic and parasympathetic fibres from the
solar plexus
–Sympathetic fibres form celiac ganglion
–Parasympathetic fibres from vagus

25. Renal Pelvis
•Proximal
expanded part of
the ureter in all
domestic
mammals OTHER
THAN THE OX
•All the papillary
ducts open in
renal pelvis
•Located within
the renal sinus

26. Renal Pelvis – Specie differences
Dog and cat - moulded around the renal crest
and extends ventrally and dorsally to form the
pelvic recesses

27. Renal Pelvis – Specie differences
Absent in the ox - papilla of each medullary lobe fit into
a minor calyx  Unite into two major calyces 
converge from both poles of the kidney to form a single
ureter

28. Renal Pelvis – Specie differences
Horse - a central cavity and two large recesses directed towards
the poles of the kidney. The mucosa of the renal pelvis produces
a mucous secretion, which accounts for the proteins normally
present in the equine urine.

29. Ureter
•Muscular tube, divided into an abdominal part and a pelvic part
•Route –
–Passes caudally in retroperitoneal space along the dorsal body wall.
–On reaching the pelvic cavity, it crosses dorsal to the corresponding
deferent duct in male animals.
–Ends by inserting into the dorsolateral surface of the urinary bladder
close to the neck, and runs obliquely intramurally for about 2cm before
opening into the lumen of the bladder

Blood Supply: Renal + Cranial vesical + prostatic
or vaginal arteries & veins
Lymphatics drain into the lumbar lymph nodes +
medial iliac lymph nodes
Innervation: parasympathetic and sympathetic
innervation

30. Urinary Bladder
•A hollow musculomembraneous
organ
•Varies in form, size and position
depending on the amount of urine
in it
•Small and globular, when contracted
and lies on the pubic bones.
Extends into the abdomen in
carnivores, but is confined to the
pelvic cavity in larger animals.
During filling it enlarges and
becomes pear-shaped.
•Divided into a cranial vertex, an
intermediate body and a caudal
neck, which is continuous with the
urethra

31. Urinary Bladder - Ligaments
Paired Lateral Ligaments
•From lateral surface of urinary
bladder to walls of pelvic cavity
•Carry umbilical arteries in
foetus
•Umbilical arteries are
transformed into round
ligaments at birth
Median ligament
•From ventral surface of bladder
to abdominal floor
•Carries urachus in foetus
•Urachus may persist in some
individuals
Rectum
Uterus
Urinary bladder

32. Urinary bladder – Interior, BS …
•Except the caudal part of the neck, bladder is covered with peritoneum, which
continues as the ligaments of the bladder onto the body walls.
•Continence depends upon elastic elements within the mucosa and on the action of
the striated urethral muscle
•No physiological sphincter in neck

•Interior of Urinary bladder:
–Trigone Area: triangular space bound by to
ureteral openings and urethral crest


Blood Supply - caudal vesical arteries and veins
Lymphatics - iliosacral lymph nodes
Innervation - sympathetic and parasympathetic
Sympathetic fibres - hypogastric nerves
Parasympathetic - pelvic nerves (pudendal nerve S3)

33. Pelvic peritoneal excavations in male animals
Please learn definitions of all terminologies displayed in this image

34. Pelvic peritoneal excavations in female animals
Please learn definitions of all terminologies displayed in this image

35. Female Urethra
•Cranially continuous with bladder
•Carries urine only



•Route:
–Neck of bladder  extends caudally on the pelvic floor  passes
obliquely through the wall of vagina  opens at external urethral
opening at the junction of vagina and vestibule, on the ventral floor.

•Species differences:
–Short and wide in the horse
–Comparatively long in the dog
–In the cow and sow the urethralis muscle encloses the suburethral
diverticulum, which opens together with the urethra into the vagina.
This arrangement can cause difficulties during catheterisation.

36. Male Urethra
Carries urine, semen and seminal secretions
Route:
•Entire route is divided into
–Pelvic part
•Preprostatic portion - from internal
bladder opening to the seminal hillock,
an oval enlargement of the urethral
crest, which protrudes into the lumen
of the urethra.
•Prostatic portion - Passes through the
prostate gland, joined by deferent and
vesicular ducts
–Penile part – from ischial arch to the tip of
glans penis EXCEPT in small ruminants
where urethra extends beyond the penis as
urethral process (vermiform appendage)
(about 4cm in sheep and 2.5cm in goat)

37. Urethra - Structure
Structure:
The urethral wall contains a venous plexus in its submucosa,
which has erectile properties that aid continence.

The urethra is surrounded by the striated urethral muscle over
most of its length. Voluntary control of the urethral muscle is
provided by somatic fibres of the pudendal nerve