Kidney of Animals

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Kidney of Animals

The urinary organs are the kidneys, ureters, bladder and urethra. The kidneys are glands that secrete the urine. The ureters are tubes, which convey the urine to the urinary bladder and the urinary bladder is a reservoir for the urine. The urine accumulates in the bladder and is then expelled through the urethra.

Kidney of Ox

  • The kidneys are two compound tubular glands in the sublumbar region. They are elongated and elliptical in outline
  • It is reddish brown in colour and their surface is marked by numerous fissures dividing them into polygonal lobes about 20 in number
  • The fissures are filled with fat. Each weighs about 600 to 700 gm The left one being usually 30 gm. or so heavier
  • They are embedded in a large amount of fat. The right kidney measures about 20 to 22.5 cm long, 10 to 12 cm wide 5 to 6 cm thick
  • The left one is slightly shorter but thicker
RIGHT KIDNEY
  • The right kidney presents two surfaces, two borders and two extremities
  • It is situated ventral to the last rib and the first two or three lumbar transverse processes but its extremities may be ventral to the 1st and 4th lumbar transverse process
  • The dorsal surface is rounded and is in contact with the sublumbar muscles. The ventral surface is less convex and related to the liver, pancreas, duodenum and colon
  • The hilus is an extensive, elliptical cavity situated at the cranial part of the ventral surface near the medial border
  • The medial border is nearly straight and lies parallel to the caudal venacava. The lateral border is convex
  • The cranial extremity is thick, lies in the renal impression of the liver and is related to the adrenal. The caudal extremity is narrow and pointed
  • The right kidney is more firmly attached than the left because of its attachment to the liver by caudate ligament
LEFT KIDNEY
  • The left kidney is variable in position. When the rumen is full, it pushes the kidney backward and across the median plane, so that it is situated on the right side behind and at a lower level than the right kidney
  • It lies below the bodies of the third, fourth and fifth lumbar vertebrae
  • When the rumen is not so full, it is slightly towards the left. It presents three surfaces
  • The dorsal surface in convex and is related to the bodies of the lumbar vertebrae and sublumbar muscles
  • The ventral surface is less convex and is related to the intestine
  • The lateral surface is flattened due to its contact with the rumen and is hence termed the ruminal surface
  • The medial border is nearly straight and is related to the abdominal aorta and ureter
  • The hilus is a deep fissure and situated on the antero-lateral aspect of the dorsal surface of the left kidney.
CORTEX AND MEDULLA OF KIDNEY
  • The cortex presents a granular appearance and is studded with numerous minute dark points, the renal or Malphigian corpuscles
  • It consists of dilated origins of the renal tubules, the Bowman’s capsule which encloses a tuft of capillaries, the glomerulus
  • The medulla is pale and presents at its junction with the cortex an intermediate vascular zone
  • The medulla consists of uriniferous tubules, blood vessels and lymphatics connected together by connective tissue
  • The straight portions of the tubules appear as conical masses called – renal pyramids (20 in number with their bases directed towards the cortex)
  • Between the pyramids a part of the cortex dips inwards forming the renal columns of Bertini
  • They present at the apex, the renal-papilla, which is enclosed or embraced by the funnel-shaped end of a tube -the calyx minor, which opens into a larger calyx major
  • Two such calyces major from the two extremities unite at the hilus to form the excretory duct, the ureter. The renal pelvis is absent

Kidney of Sheep and Goat

  • The kidneys are bean shaped and smooth in sheep and goat.
  • In position, they resemble ox except that the right one is usually a little further back and lies under the first three lumbar transverse process
  • The hilus is present at the middle of the medial border
  • They are similar to each other and very much close to the dog and very difficult to distinguish them
  • They are more regular in shape than dogs, being protected from the distorting pressures by thick masses of fat
  • The fat cushion makes the left kidney less subject to the displacement

Kidney of Horse

  • The surfaces are smooth and are not lobulated. The average weight is about 700 gm
  • The right kidney weighs 30 to 60 gm. more than the left. The right kidney is 15 cm long, 15 cm wide and 5 cm wide
  • The right is shorter, wider and thicker than the left
  • The right kidney resembles the heart of playing cards while the left is bean shaped
  • The right is situated under the vertebral end of the last two or three ribs and 1st lumbar transverse process
  • The left one is under the last rib and the first two or three lumbar transverse processes
  • The hilus is about the middle of the medial border in the form of a deep notch in both kidneys
  • The dorsal surface of the right kidney is convex and is related chiefly to the diaphragm whereas the ventral surface is concave and related to the liver, pancreas, caecum and adrenal gland
  • The cranial extremity of the right is thicker and rounded, lies in the renal impression of the liver
  • The caudal extremity is thinner and narrower
  • The caudal extremity of the left kidney is wider and thicker
  • The hilus leads into a renal sinus in the interior for the lodgment of the renal pelvis, which is the dilated origin of the ureter
  • The inner central part of the medulla forms a concave ridge – the renal crest, which presents numerous openings – the area cribrosa through which the large ducts open into the renal pelvis

Kidney of Pig

  • Smooth and bean shaped kidneys present in pig.
  • It is more elongated
  • The right and left kidneys are almost symmetrically placed ventral to the transverse processes of the first four lumbar vertebrae, but the left is often a little further forward than the right one
  • The right kidney has no contact with the liver
  • The hilus is about the middle of the medial border
  • Each kidney possesses two calyces major and about a dozen of calyces minor

Kidney of Dog

  • The kidneys of dog are smooth and bean shaped. The average weight is 50 to 60 gm
  • The right kidney is situated under the bodies of the first three lumbar vertebrae
  • The left kidney is about the level of the 2nd , 3rd and 4th lumbar vertebrae but when the stomach is full, it is pushed to one vertebra further back, so that the cranial pole may be placed behind the caudal pole of the right
  • The hilus is about the middle of the medial border. The medulla shows a renal crest

Kidney of Rabbit

  • The kidneys of rabbit are smooth and bean shaped
  • Right kidney is situated below the proximal end of the last rib and first two lumbar transverse processes and the left kidney is placed below the bodies of 2nd and 3rd lumbar vertebrae
  • The kidneys are unipyramidal

Kidney of Fowl

  • The kidneys of fowl are brown coloured elongated structures and lie along each side of the vertebral column from the vertebral end of the 6th rib into the iliac fossa
  • Each is made up of 3 or 4 lobes as cranial, middle and caudal portions. It is friable in nature
  • The lobes are not well defined
  • The surfaces are rough due to projected surfaces of the renal tubules
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