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 right and left kidneys and urinary bladder of adult (1-2 years) male and female domestic cats (Felis catus).
Materials and methods: For the present study, ten healthy adult domestic cats of both genders (5 males and 5 females), with a mean body weight of 4300.0 ± 0.4 grams, were used. The cats were local domestic cats collected in Babylon Province, Iraq, and examined at the College of Veterinary Medicine, Al-Qasim Green University, Iraq. Although both sexes were included, the present study did not conduct a separate sex-based comparison because the main objective was to explain the general gross morphology and morphometry of the kidneys and urinary bladder in adult domestic cats. 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. Laparotomy was performed through the midline approach to expose both right and left kidneys and the urinary bladder to evaluate their gross morphology and morphometry.
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 occupied a more cranial position and appeared more fixed than the left, which appeared more caudal and mobile. The kidneys had a smooth surface, were unilobar and unipapillary, with an obvious renal crest and hilus. They were covered with a thin fibrous capsule and perirenal fat. As a result of morphometric analysis, the right kidney was slightly larger than the left in terms of weight, length, and thickness. The internal structure consisted of three zones, including the renal cortex, renal medulla, and renal pelvis. The renal medulla contained medullary tissue that converged into a single renal papilla, a feature specific to cat kidneys. 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. It was pear-shaped and consisted of an apex, body, and neck.
Conclusion: In the present gross examination, no obvious gross morphological differences were observed in the external morphology of either the kidneys or the urinary bladder between the sexes.