Gross Morphological Study of Kidneys and Urinary Bladder in Adult Domestic Cats (Felis catus)

Abstract

Introduction: The urinary system of domestic cats has important anatomical and clinical relevance in veterinary medicine. The present study aimed to characterize the gross anatomy and morphometry of the kidneys and urinary bladder of adult (1-2 years) male and female domestic cats (Felis catus).
Materials and methods: Ten healthy adult domestic cats (5 males and 5 females), with a mean body weight of 4300.0 ± 0.4 grams, were collected from Babylon Province of Iraq, examined at the College of Veterinary Medicine, Al-Qasim Green University, Iraq. Both sexes were included, but no sex-based comparison was conducted as the study aimed to describe the general gross morphology and morphometry of the kidneys and urinary bladder. General anesthesia was induced by intramuscular injection of xylazine hydrochloride 2% (20 mg/mL) at a dose of 1 mg/kg and ketamine hydrochloride 10% (100 mg/mL) at a dose of 10 mg/kg. A midline laparotomy was then performed to expose the kidneys and urinary bladder for evaluation.
Results: The urinary system included two kidneys, ureters, urinary bladder, and urethra, as in mammals. The kidneys were bean-shaped, paired retroperitoneal organs located in the lumbar region. The right kidney was relatively more cranial and fixed, in contrast to the left kidney, which was relatively more caudal and mobile. The kidneys had a smooth surface, were unilobar and unipapillary, with an obvious renal crest and hilus covered by a thin fibrous capsule and perirenal fat. The morphometric findings indicated that the right kidney was slightly larger than the left in terms of weight, length, and thickness. The internal structure included three zones, namely the renal cortex, renal medulla, and renal pelvis. The renal medulla contained medullary tissue converging into one renal papilla, which is specific for the kidneys of cats. The urinary bladder appeared as a smooth, muscular, hollow organ located mainly in the pelvic cavity when empty and extending cranially into the abdominal cavity when distended. The urinary bladder was pear-shaped and consisted of an apex, body, and neck.
Conclusion: Gross examination revealed no obvious morphological differences between the sexes in the external appearance of the kidneys or urinary bladder.