Excretion

• Excretion


  The removal of waste products of metabolism and substances in excess of requirements
• Organs involved in excretion


  • Lungs
  • Kidneys
  • Liver
• Lungs


  • Responsible for excreting carbon dioxide, a byproduct of respiration
• Kidneys


  • Responsible for excreting urea, excess water and ions
• Kidney function


  1. Blood flows into glomerulus

  2. Filtration occurs

  3. Filtrate collects in renal capsule

  4. Substances reabsorbed from filtrate

  5. Urine formed and excreted
• Glomerulus


  Coiled knot of capillaries in the kidney
• Renal capsule


  Cup-shaped organ that collects the filtrate from the glomerulus
• Renal tubule


  Looping structure that the filtrate passes through
• Collecting duct


  Tube that transports urine from the kidney to the bladder
• Assimilation


  The uptake and use of nutrients by cells
• Liver's role in assimilation


  • Removes amino acids from blood and uses them to synthesize proteins
• Deamination


  The removal of the nitrogen-containing part of amino acids to form urea