Urinary System Overview

Urinary System

• The urinary system transports urine from the kidneys to the bladder
• In women, the kidneys are positioned near the ovaries
• Kidneys are bean-shaped and heavily take up space near major blood vessels
• Kidneys take blood from the abdominal aorta
• Kidneys drain into the inferior vena cava

Kidney Functions

• Filtration: Removing waste products from the blood.
• Reabsorption: Returning essential substances to the blood
• Excretion: Eliminating excess wastes and fluids as urine.
• Regulation of overall blood volume and blood pressure
• Maintenance of appropriate electrolyte balance and maintaining acid/base balance
• Production of erythropoietin(hormone) which stimulates the production of red blood cells, and creation of other hormones

Kidney Location and Position

• Positioned in the upper part of the posterior abdominal wall
• Kidneys are on either side of the vertebral column.
• The right kidney is positioned at the level of T12 to L3
• The left kidney is positioned at the level of T11 to L2
• The left kidney is situated higher than the right kidney

Urinary System Organs

• Two kidneys
• Two ureters
• One urinary bladder
• One urethra

Ureters

• Channels that transport urine from the kidneys to the bladder
• Approximately 25-30 cm in length
• Pass through the linea terminalis to enter the pelvis minor
• Travel along the lateral wall of the pelvis to reach the bladder

Bladder

• Reservoir for urine
• Located posterior to the symphysis pubis
• Anterior to the uterus in females, and anterior to the rectum in males.
• Normal capacity is approximately 220 mL but can hold up to 500 mL
• Empty bladder lies in the pelvis minor and when full can extend up to the level of the umbilicus.

Urethra

• In males, 20 cm long
• In females, 3-5 cm long
• The urethra contains Two sphincter muscles, internal sphincter and external sphincter.

Nephrons

• Functional units within the kidneys
• Averages over a million nephrons per kidney,
• Urine formation occurs within nephrons

Urine Formation Stages

• Filtration
• Reabsorption
• Excretion

Renal Blood Supply

• Renal artery arises from the abdominal aorta
• Renal vein drains into the inferior vena cava

Structures of the Kidney

• Renal pelvis
• Calyx's minor & major
• Medulla and Cortex
• Other structures, such as the hilum and renal columns

Urethra segments

• Pars prostatica (in male)
• Pars membranacea (in male)
• Pars spongiosa (in male) - which continues to the tip of the penis.

Test your knowledge on the urinary system and its functions, focusing on kidney anatomy and physiology. This quiz covers the roles of the kidneys in filtration, reabsorption, and regulation of blood volume and pressure. Ideal for those studying human biology or anatomy.