Genitourinary System Overview

Genitourinary System

• The genitourinary system encompasses the urinary system and the reproductive system.

Urinary System

• The urinary system consists of two kidneys, two ureters, a urinary bladder, and a urethra.
• The male urethra serves as a common pathway for urine and semen.
• The prostatic urethra receives the two ejaculatory ducts.

Kidneys

• Kidneys are reddish-brown organs located behind the peritoneum, high on the posterior abdominal wall, on either side of the vertebral column.
• Each kidney has a medial concave border with a notch called the hilum.
• The hilum transmits the renal vein, renal artery, ureter, and lymph vessels.
• The suprarenal/adrenal gland sits on the upper pole of each kidney.

Renal Structure

• Each kidney has a dark-brown outer cortex, light-brown inner medulla, and a renal sinus.
• The medulla consists of about a dozen renal pyramids.
• The cortex displays striations known as medullary rays.
• The renal sinus (or renal pelvis) contains the expanded upper part of the ureter.
• It branches into two or three major calyces, each further dividing into two or three minor calyces.

Ureter

• Ureters are muscular tubes extending from the kidneys to the posterior surface of the urinary bladder.
• Each ureter is about 25cm long.
• The ureter has three constrictions along its course:
  • Where the renal pelvis joins the ureter.
  • Where it bends as it crosses the pelvic brim.
  • Where it pierces the bladder wall.

Urinary Bladder

• The bladder is a muscular sac that stores and excretes urine.
• Its volume capacity is 500ml.
• The two ureters open into the urinary bladder, and the urethra starts at the internal urethral orifice.
• The internal surface of the bladder base is called the trigone.
• The superior angles of the trigone correspond to the ureter openings, and the inferior angle corresponds to the internal urethral orifice.

Male Urethra

• The male urethra is a 20cm long muscular tube.
• It extends from the internal urethral orifice of the urinary bladder to the external urethral orifice on the glans penis.
• It's divided into prostatic, membranous, and penile parts.
• It's a common pathway for both urine and semen.

Female Urethra

• The female urethra is 4cm long.
• It begins at the urinary bladder and terminates at the external urethral orifice in the vestibule.
• It's anterior to the vaginal opening.

Male Reproductive System

• The male reproductive system consists of:
  • Testes
  • Ducts: Epididymis, ductus deferens, ejaculatory duct, urethra
  • Accessory sex glands: seminal vesicles, prostate gland, bulbourethral glands
  • External genitalia: penis, scrotum

Testes

• Each testis is an oval structure located in the scrotum.
• Each testis contains many lobules with seminiferous tubules (1 to 4 per lobule).
• The seminiferous tubules open into a network of channels called the rete testis.
• Small efferent ductules connect the rete testis to the epididymis.
• Interstitial cells (Leydig cells) produce testosterone between the seminiferous tubules.

Epididymis

• The epididymis is a coiled tube located posterior to the testes, approximately 6 meters long.
• The tube emerges from the epididymis tail as the vas deferens, entering the spermatic cord.
• The epididymis provides storage space for spermatazoa, allowing their maturation.

Vas Deferens

• The vas deferens is a thick-walled tube (approximately 45 cm).
• It conveys mature sperm from the epididymis to the ejaculatory duct and the urethra.
• It originates from the epididymis's lower end (tail).
• The terminal part of the vas deferens dilates to form the ampulla of the vas deferens.
• It merges with the duct of the seminal vesicle to form the ejaculatory duct, which opens into the urethra.

Seminal Vesicles

• Seminal vesicles are two lobulated organs on the bladder's posterior surface.
• Each vesicle's terminal part joins the vas deferens to form the ejaculatory duct.
• Function: to produce a secretion added to the seminal fluid.

Prostate

• The prostate is a fibromuscular glandular organ surrounding the prostatic urethra.
• The two ejaculatory ducts pierce the prostate.

Bulbourethral Glands (Cowper's Glands)

• Small glands (pea-sized) situated near the base of the penis.

Scrotum

• The scrotum is a pouch of the lower anterior abdominal wall, separated by a raphe.
• It holds the testes, epididymides, and lower parts of the spermatic cords.

Penis

• The penis has a fixed root and a free-hanging body.
• At the distal extremity is the glans penis.
• The glans penis tip contains the external urethral meatus (opening of the urethra).

Female Reproductive System

• The female reproductive system includes:
  • External genitalia (vulva): labia majora, labia minora, vestibule of the vagina, clitoris
  • Internal genitalia: ovaries, uterine/fallopian tubes, uterus, vagina

Ovaries

• Located in the upper pelvic cavity, on either side of the uterus.
• Functions: produce ova, estrogen, and progesterone.

Uterine Tubes

• Extend from the uterus to the ovaries, connecting the uterine cavity to the peritoneal cavity.
• Subdivided into four parts; convey fertilized eggs to the uterus by ciliary action and muscular contraction.
• Fertilization occurs within the tube.

Uterus

• The organ of gestation where a fertilized egg implants and develops into a baby until birth.

Vagina

• A muscular tube (approximately 10 cm) extending from the cervix to the vaginal orifice in the perineum.
• Located between the bladder (anteriorly) and the rectum (posteriorly).

This quiz covers the essential components of the genitourinary system, focusing on both the urinary and reproductive systems. Test your knowledge on the structure and function of the kidneys, ureters, bladder, and associated ducts.