excretory system

• Osmotic balance


  Maintaining the balance of water and solutes in the body
• Metabolic wastes


  Substances like carbon dioxide and nitrogenous wastes that need to be excreted
• Urinary system


  The system focused on the kidneys, bladder, ureters, and urethra
• Nephron


  • The functional unit of the kidney
  • Processes waste products from the blood to create urine
• Glomerulus


  A specialized mass of capillaries surrounded by the Bowman's capsule
• Filtrate


  The fluid that enters the Bowman's capsule from the glomerulus, containing water, glucose, amino acids, salts, ions, and urea
• Filtration and reabsorption in the nephron

  1. Filtrate enters Bowman's capsule

  2. Substances reabsorbed in proximal tubule

  3. Water reabsorbed in loop of Henle

  4. Substances secreted in distal convoluted tubule

  5. Urine formed in collecting duct
• Diffusion and facilitated diffusion


  Transport processes that don't require ATP and move substances down their concentration gradient
• Active transport


  Transport process that requires ATP to move substances against their concentration gradient
• Reabsorption


  When substances move from the filtrate back into the interstitial fluid
• Secretion


  When substances move from the interstitial fluid into the filtrate
• The proximal tubule, loop of Henle, and distal convoluted tubule are important for pH regulation
• The collecting duct regulates the amount of water reabsorbed based on hormonal control
• Urea is reabsorbed by diffusion in the collecting duct
• Dialysis


  A process that filters the blood and assists with osmoregulation for people with severely compromised kidney function
• Nephrologists are medical professionals who specialize in kidney function
• Urea


  The liquid waste
• Urinary system


  Also known as the renal system, helps the body to get rid of liquid waste known as urea
• Urinary system


  • Filters blood and creates urine as a waste by-product
• Parts of the urinary system

  • Kidneys
  • Ureters
  • Bladder
  • Sphincter muscles
  • Urethra
• Kidneys


  Two bean-shaped organs that help the body pass waste as urine, filter blood before sending it back to the heart, and release hormones to regulate blood pressure and control the production of red blood cells
• Ureters


  Thin narrow tubes that carry urine from the kidneys toward the bladder, with muscles that constantly relax and tighten to force urine downward
• Bladder


  A muscle sack in the pelvis that stores urine released from the ureters, allowing urination to be controlled and infrequent, can hold around 400-500 millilitres of urine
• Sphincter muscles


  Circle-shaped muscles that help keep urine from leaking by closing securely like a rubber band over the opening of the bladder
• Urethra


  The tube that allows urine to pass outside the body, with the brain signalling the bladder muscles to tighten and the sphincter muscles to relax to allow urination
• The brain signals the bladder muscles to tighten which squeezes urine out of the bladder, and at the same time signals the sphincter muscles to relax to let urine exit the bladder through the urethra tube
• Tips to keep the urinary system healthy

  • Drink enough fluids, especially water
  • Exercise regularly and keep a healthy weight
  • Eat plenty of high fiber foods
  • Use the washroom often and when needed, taking enough time to fully empty the bladder while urinating