Human Anatomy - Urogenital System Lecture 9

Urogenital System

• The genitourinary system consists of the reproductive system and the urinary system.

Urinary System

• Consists of:
  • Two kidneys
  • Two ureters
  • Urinary bladder
  • Urethra
• Kidneys:
  • Two bean-shaped organs in the posterior part of the abdominal cavity
  • Help the body pass waste as urine
  • Functions:
    • Maintain fluid balance
    • Filter blood
    • Create hormones that help produce red blood cells
  • Each kidney has:
    • Two poles (upper and lower)
    • Two borders (medial and lateral)
    • Upper pole is related to the adrenal gland
    • Medial border has the hilum of the kidney
• Ureters:
  • A pair of muscular tubes that extend from the kidneys to the urinary bladder
  • Each ureter begins at the funnel-shaped renal pelvis
  • Length: about 25cm
  • Function: transportation of urine from the kidneys to the urinary bladder
  • Penetrate the posterolateral angle of the urinary bladder by slit-like opening (intramural oblique course)
• Urinary Bladder:
  • A muscular sac that contracts and empties urine through the urethra
  • Has:
    • Apex: anterior
    • Base: posterior (ureters enter at superolateral angles)
    • Neck: inferior end (exit of urethra and in males lies on the prostate)
• Urethra:
  • Function: transports urine to the exterior of the body
  • Length:
    • Male urethra: 18-20 cm
    • Female urethra: about 4 cm
  • Sphincters:
    • Internal urethral sphincter at the bladder neck (involuntary)
    • External urethral sphincter (voluntary)

Male Reproductive System

• Consists of:
  • Gonads (Testes)
  • Ducts
  • Accessory glands
  • External genitalia
• Testes:
  • Hang within the scrotum (protection from body temperature)
  • Function:
    • Secrete testosterone (male sex hormone)
    • Produce sperms (male gametes) at a rate of ½ billion/day
• Epididymis:
  • A coiled tube (7 m) in length
  • Function: stores and protects sperms and facilitates their functional maturation
  • Tail of the epididymis is continuous with the vas deferens
• Vas deferens:
  • A muscular tube (40–45 cm long)
  • Function: peristaltic contractions propel semen through the duct
• Accessory glands:
  • Prostate (below the neck of the urinary bladder)
  • Seminal vesicle (behind the base of the urinary bladder)
  • Function:
    • Activation of sperm
    • Nutrition of sperm
    • Provide a fluid media for sperm propulsion

Female Reproductive System

• Consists of:
  • Gonads (Ovaries)
  • Ducts
  • Accessory glands
  • External genitalia
• Ovaries:
  • Paired organs
  • Location: in the lateral pelvic wall
  • Function:
    • Produce female gametes, ovum (one per month)
    • Secrete female sex hormones, estrogens and progesterone
• Uterine Tubes (Fallopian tubes):
  • Extend from the superolateral angles of the uterus to the ovaries
  • Site of fertilization (ampulla)
  • Function: transport the fertilized ovum towards the uterus
• Uterus:
  • Pear-shaped organ
  • Divided into:
    • Body (largest portion)
    • Fundus (portion superior to the attachment of the uterine tubes)
    • Cervix (inferior portion)
• Vagina:
  • Elastic, highly distensible, muscular tube
  • Extends between the cervix and the exterior
  • Related anteriorly to the urethra and posteriorly to the rectum and anal canal

Identify and describe the organs and structures of the urinary and reproductive systems, including the kidneys, ureters, bladder, urethra, and male and female reproductive systems.