Excretory System Overview

The Excretory System

• The excretory system, also known as the urinary system, removes waste and excess fluids from the body.
• Key structures include the kidneys, ureters, bladder, and urethra
• The kidneys are the primary organs filtering blood.
• The ureters carry urine from the kidneys to the bladder.
• The bladder stores urine until it is expelled from the body.
• The urethra is the tube through which urine is discharged.

Purpose of the Excretory System

• Removes waste products like urea (a by-product of protein breakdown).
• Removes unneeded substances.
• Protein breakdown in the liver results in ammonia, which is converted into less toxic urea.
• Blood transports urea to the kidneys for removal.

Kidney Function and Urine Formation

• Four phases are involved in urine formation in the kidneys:
  • Filtration: Blood is filtered, removing water and small molecules. Blood cells remain in the blood.
  • Reabsorption: Essential substances like water, salts, and glucose are reabsorbed into the bloodstream.
  • Secretion: Other waste products are added to the filtrate.
  • Excretion: The remaining waste products are expelled from the body as urine.
• About 119 ml of the filtered fluid is reabsorbed back into the blood.
• The remaining 1 ml of the filtered fluid is excreted as urine.
  • Urine is approximately 95% water and 5% waste.

Kidney-Related Diseases

• Kidney stones: Hard deposits of minerals and salts formed in the kidneys or urinary tract.
• Gout: Arthritis caused by uric acid crystals in the joints.
• Urinary Tract Infections (UTIs): Infections caused by bacteria in the urinary tract. Common types include urethritis (urethra infection), cystitis (bladder infection), and pyelonephritis (kidney infection).

Kidney Dialysis

• A procedure used to remove waste and excess fluid from the blood when the kidneys cannot function properly.
• Two types:
  • Hemodialysis (HD): Blood is filtered outside the body. The process takes 3-4 hours, 3 times a week.
  • Peritoneal Dialysis (PD): A solution is placed in the abdomen, and waste products are removed via osmosis/diffusion. The procedure takes 30 minutes, 4 times a day and can be done at home.

Explore the vital functions of the excretory system in this quiz. From the components like kidneys and urethra to the process of urine formation, test your understanding of how waste and excess fluids are removed from the body. Perfect for students studying biology or human physiology.