Renal system

• Renal system


  Responsible for osmoregulation and urine production
• Osmoregulation


  Maintains the amount of water in our blood (water potential of blood)
• Osmoregulation


  Important for homeostasis
• Nephrons


  Responsible for the reabsorption of water within the kidney
• Osmoreceptors


  Detect changes in the amount of water in the blood, located in the hypothalamus
• Antidiuretic hormone (ADH)


  Released when a person is dehydrated, meaning there is less water in the blood (low water potential)
• ADH targets the kidneys


  Increases water reabsorption from urine into the blood
• ADH


  Stimulates an increase in the amount of aquaporins present in cells of collecting duct
• Increase in aquaporins in collecting duct


  Results in more water being reabsorbed into the blood
• there is no information on whether the person has normal kidney function which may impact the results. To prove levels of hydration, blood tests would need to be done to measure concentration and levels of ADH.
• Sustained running


  1. Increases fluid loss due to increased respiratory rate (as expired water vapour)

  2. Increases fluid loss due to sweating due to the hot weather

  3. Increases fluid loss due to heat produced (by the muscles) during (prolonged) exercise

  4. Fluids will need to be replaced to prevent dehydration
• Prolonged exercise in hot weather

  Risks the body not being able to compensate without drinks
• Increased thirst sensation (caused by raised ADH levels)


  Should not be ignored
• Water is vital to ensure waste products can be expelled and to ensure the body can function appropriately
• Drinks are essential to stop the body overheating
• Overheating


  Can affect enzyme behaviour and alter electrolyte levels, impairing normal cellular behaviour (such as neurones, cardiac cells, muscles)
• Water is necessary to prevent cramps which can slow down your marathon time or cause other injuries
• Drink breaks are important to ensure that you can maintain a stable pace throughout the race and ensure your body is working effectively
• Loading up on water prior to the race


  Can cause increased urination which will affect your ability to maintain pace and puts unnecessary pressure on your body and can increase stress
• Electrolytes must be replaced when running
• Fluids containing electrolytes can prevent other health conditions such as confusion, exhaustion and seizures
• Failure to replace electrolytes when undertaking high intensity exercise can be extremely dangerous