Topography and Features of Urinary Organs in Canines

Urinary Organs: Topography and Features

Overview of Objective

  • The session focuses on describing the topography and features of the urinary organs located in the abdominal and pelvic cavities, specifically in canines.

1. Anatomical Context

  • Viewpoint: Left lateral view of the urinary organs.
  • Divisions:
    • Abdominal cavity
    • Pelvic cavity

2. Kidneys

  • Positioning:
    • Urinary organs are located in the sublumbar region.
    • Right kidney is positioned below the 13th thoracic vertebra.
  • Kidney Structure:
    • Cranial and Caudal Poles: Each kidney has both a cranial and caudal pole.
    • Borders:
    • Lateral Border: Outer side of the kidney.
    • Medial Border: Inner side of the kidney where the ureter exits.
  • Ureter:
    • The ureter leaves the kidney at the medial border.
    • It travels retroperitoneally in the abdominal cavity.
    • Structure: Long, thin tubular in shape.
    • It enters the bladder at the neck region, penetrating the dorsal wall of the bladder.

3. Bladder

  • Characteristics:
    • Size, shape, and position of the bladder can vary due to its distensible nature.
    • Contracted State: Located within the pelvic cavity.
    • Distended State: Often extends into the abdominal cavity.
  • Anatomical Parts of the Bladder:
    • Vertex: Most cranial part.
    • Body: Intermediate section.
    • Neck: Region where the bladder opens into the urethra.
  • Shape: The bladder is described as pear-shaped.

4. Urethra

  • Introduction: The urethra exits from the bladder at the neck region.
  • Structure in Males:
    • The urethra is further categorized into two main parts:
    • Pelvic Part: Located in the pelvic cavity.
    • Penile Part: Located within the penis.
    • Specific Sections of the Pelvic Part: Includes pre-prostatic, prostatic, and post-prostatic portions.
  • Muscle Composition: The urethra is thickened by the urethral muscle.
  • Pathway: In males, the urethra extends from the internal uterine orifice to the distal extremity of the penis, opening externally via the urethral process.

5. Structures Related to the Urethra

  • Penile Cross-Section:
    • Observation illustrates the urethra surrounded by spongy tissue that is significant in the male reproductive system.
  • Descent of the Urethra:
    • The urethra runs from the root of the penis, surrounded by spongy tissue, to exit at the urethral process.

6. Male vs Female Differences in Urinary System

  • Male Anatomy:
    • Includes the prostate gland contribution to the urethra.
    • Ureter juxtaposition with the ductus deferens.
  • Female Anatomy:
    • Ureters similarly leave the kidneys as in males, leading to the urinary bladder's dorsal wall.
    • Urethra joins with the reproductive structures (junction of vagina and vestibule) and opens at that junction, relevant for the female reproductive system.

7. Conclusion

  • Recap of the importance of understanding the anatomical features and positioning of the urinary organs in both male and female canines for any study related to veterinary anatomy.
  • The concepts covered include the anatomical structure, functional pathways, and structural adaptations associated with urinary organs.