Y8 Review of Excretory System

Systems of the Human Body

Review of Excretory System

• The excretory system is essential for eliminating waste products from the body to prevent toxic buildup.

Organs Involved in the Excretory System

• Kidneys:

  • Excrete water, urea, and salts.

  • Prevent toxic buildup in the body.

• Lungs:

  • Excrete carbon dioxide (CO2) and water.

• Skin (Sweat Glands):

  • Excretes water, urea, and salts to help regulate body temperature and keep us cool.

• Organisms rely on chemicals for metabolism (converting food and drink into energy).

• It is important to excrete waste products that can be toxic or poisonous, such as urea, salts, and carbon dioxide when present in high concentrations.

Purpose of the Excretory System

• The excretory system is crucial for:

  • Eliminating waste products via kidneys and bladder.

  • Supporting survival by ensuring the removal of metabolic waste like water, urea, and salts.

Key Components of the Excretory System

• Kidneys:

  • Main organs responsible for filtering blood and producing urine.

• Kidney Vein (Renal Vein):

  • Takes deoxygenated blood away from the kidneys.

• Ureter:

  • A 20 cm long tube through which urine passes from the kidneys to the bladder.

• Kidney Artery (Renal Artery):

  • Supplies the kidneys with oxygenated blood.

• Bladder:

  • A muscular bag that can hold up to 1 liter of urine.

  • About 300 mL (less than a can of soda) is enough to trigger the urge to urinate.

• Urethra:

  • The tube that allows urine to drain from the bladder during urination.

• Sphincter Muscle:

  • A ring of muscle that closes the bladder, controlling the excretion of urine.

  • Relaxes to allow bladder emptying.