Untitled Quiz

Urinary System Overview

• Urinary system comprises organs crucial for eliminating waste and maintaining fluid balance
• Key organs include two kidneys, two ureters, one urinary bladder, and one urethra

Objectives of the Lecture

• Students should identify organs of the urinary system
• Students should understand the anatomy of the kidneys, their location, and relations to other organs
• Students should understand the anatomy of the ureters, including constrictions
• Students should understand the anatomy of the urinary bladder, including its parts
• Students should understand the anatomy of the male urethra and its parts
• Students should understand the anatomy of the female urethra and differences between male and female urethra

Kidneys

• Positioned on either side of the vertebral column
• Extend from T12 to L3 vertebrae
• Right kidney sits lower than the left kidney
• Dimensions are approximately 12 cm long, 6 cm wide, and 3 cm thick
• Kidneys have two surfaces, two borders, and two ends
  • Lateral border is convex, medial border convex at both ends, concave in the middle
  • Middle of the medial border is the hilum, providing passage for vessels and nerves to the kidney

Kidney Structure

• Differentiated into outer cortex and inner medulla
• Medullary pyramids present in the medulla
• Calyces collect urine from pyramids
• Urine collection into renal pelvis
• Pelvis continues as ureter

Kidney Relations (Anterior Surface)

• Right Kidney:

  • Right suprarenal gland
  • Duodenum
  • Liver
  • Colon
  • Small intestine

• Left Kidney:

  • Left suprarenal gland
  • Spleen
  • Pancreas
  • Stomach
  • Colon
  • Small intestine

Kidney Relations (Posterior Surface)

• Diaphragm
• Muscles of posterior abdominal wall:
  • Psoas major
  • Quadratus lumborum
  • Transversus abdominis

Kidney Coverings

• Fibrous capsule
• Perirenal fat
• Renal fascia
• Pararenal fat

Ureters

• Two muscular tubes, one on each side
• Carry urine from kidneys to urinary bladder
• Length ranges from 25-30 cm
• Course partly in the abdomen and partly in the pelvis
• Continuation of the renal pelvis
• Open into the postero-superior angle of the urinary bladder

Ureters (Constrictions)

• Three constrictions during passage:
  • Pelvi-ureteric junction
  • Crossing of common iliac artery
  • Uretero-vesical junction

Urinary Bladder

• Hollow, strong muscular organ
• Urine reservoir
• Located in pelvic cavity, behind pubic bones
• Shape is a three-sided pyramid
• Capacity of 220 cc, accommodates up to 500 cc
• Apex posterior to upper part of symphysis pubis, continuous with median umbilical ligament
• Base directed posteriorly
• Three surfaces, one superior and two inferolateral
  • Related to seminal vesicles, vas deferens, cervix of uterus, and anterior wall of vagina

Male Urethra

• 20 cm long, divided into 3 parts:
  • Prostatic: 3 cm, widest, begins at urinary bladder neck, ejaculatory duct opens into prostatic urethra
  • Membranous: 1 cm, narrowest, shortest, surrounded by sphincter urethra
  • Spongy: 16 cm, longest, traverses penis, ends at external urethral orifice

Female Urethra

• Very short, approximately 4 cm
• Begins at neck of bladder, upper part surrounded by sphincter urethra
• Shorter, wider, and more dilatable compared to male urethra