Kidney

• what 3 things do the kidneys regulate

  1. ions
  2. water
  3. waste (urea)
• deamination


  the conversion of excess amino acids into fats and carbohydrates
• what is the main job of the kidney

  to filter the blood, regulating ion & water levels and removing waste
• water regulation

  • prevents cells from bursting if there's too much water
  • or shrinking if the water content is low

  -removed from body as urine or sweat
• ion regulation

  sodium & potassium ions

  -can be lost through sweating as well

  • if the content is too high or too low, it can damage our cells
• nephrons

  tiny structures in the kidney that filter out small substances
• tubules

  absorbs anything small (water, glucose, urea, amino acids), and selectively reabsorbs useful substances later on

  
  

  -this is called a filtration process
• how is water regulated in the kidneys?

  the hypothalamus in the brain detects the concentration of water in the body

  -if water concentration is low:

  - signal is sent to the pituitary gland

  - ADH (anti-diuretic hormone) is released

  - tells the kidney tubules to reabsorb more water -> increases the water content in the blood -> less urine

  -if water concentration is high:

  - stops sending signals to the pituitary gland

  - less ADH production

  - tells the kidney tubules to reabsorb less water -> more urine
• negative feedback loop


  the regulation of water in the body by the kidneys is an example of a negative feedback loop

  -the body is constantly monitoring water levels

  -adjusting them to make them balance
• how is urine made

  urea is absorbed from the glomerulus into the bowmen's capsule

  - only certain amounts of water and ions are reabsorbed

  - no urea is reabsorbed

  all non-reabsorbed liquids make its way down the collecting duct and is classified as urine
• anatomy of the urinary system

  renal arteries- imports blood from the heart

  renal veins- exports blood out of the kidney

  ureters- transports urine from the kidney to the bladder

  bladder- holds urine

  urethra- excretes the urine
• kidney failure

  treatment: dialysis or kidney transplant

  mild kidney diseases can be treated with medication
• dialysis machines

  artificial kidneys to help filter blood

  disadvantages:

  1. treatment is time-consuming (visit hospital 3-4 a week, and each time it takes 3-4 hrs of treatment)
  2. expensive
  3. can lead to infections & blood clots
• kidney transplant

  a surgical procedure where the patient receives a new kidney from a donor (recently dead or still alive)

  main risk: the body will reject the organ and it will be attacked by the patient's own immune system

  medication to suppress the immune system can be used but doesn't always work

  advantage: cheaper

  disadvantage: not enough organs available