Biology 2.6

• What are the 2 functions of the kidney

  •Regulate the water content of blood

  •remove waste products from the blood (excretion)
• One of the kidneys tasks is to take waste substances from the blood and pass them to the bladder, where they are stored until they can pass out of the body
• How does blood enter the kidney

  Renal artery
• how does the blood leave the kidneys

  Through the renal vein
• What is the function of kidneys

  Organs Which filtrate your blood
• What happens when blood passes out of the kidneys through the renal vein

  Travels back to the heat along the vena cava and then around the body
• What is the function of the ureter

  A tube that carries urine from the kidney to the bladder
• What is urine

  A mixture of urea, water and salts that is made in the kidney and stored in the bladder
• What does the bladder store

  Urine
• What is the function of the urethra

  Carries urine from the bladder out of the body
• What is meant by the term excretion

  Removal of waste products by the kidneys
• How does blood enter the kidneys

  Renal artery
• What do the kidneys remove from the blood

  Excess salts

  excess waters

  urea
• We’re does the blood leave the kidney

  Renal vein and travels to the heart via the vena cava
• What do the waste products fTom the blood form

  Urine
• Where does the urine travel once it’s filtered

  •Down tubes called ureters to be stored in the bladder then finally it leaves the body through the urethra
• Where does ultrafiltration take place

  Capillary knot
• Why is pressure in the capillary knot very high?

  •so ultrafiltration can take place
• How is high pressure generated in the capillary knot?

  •The artiole bringing the blood to the capillary knot is wider than the one taking it away
• Why aren't proteins and blood cells filtered during ultrafiltration?

  •Too big to be filtered
• What small molecules are filtered during ultrafiltration?

  Water

  Salts

  Glucose

  Urea
• Where do the small molecules move to after they've been filtered during ultrafiltration?

  •They move to the filtrate in the bowmans capsule
• What is selectively reabsorbed during ultrafiltration?

  •Glucose (needed for respiration)

  Some water

  Some salts
• Where does the remaining waste products go after selective reabsorption has occurred?


  •collecting duct before being excreted
• How can we identify kidney failure?

  •Presence of blood cells in the urine
• How can kidneys fail?

  Infection

  Bad case of poisoning

  Injury with a severe loss of blood

  Very high blood pressure
• What is ADH?

  Antidiuretic hormone
• What happens when there is too much water in the blood?

  •Brain detects water levels are too high

  Decrease in the secretion of ADH

  Kidneys reabsorb less water

  Blood water levels return to normal

  Higher volume of urine and lower concentration of urea is produced
• What happens when there is too little water in the blood?

  •Brain detects too little water in blood

  Increase in the secretion of ADH

  Kidneys reabsorb more water

  Blood water levels return to normal

  Lower volume of urine and higher concentration of urea produced
• How is dialysis carried out?

  •Blood is taken from an artery and is pumped through tubes with very thin walls made of selectively permeable membranes.

  Blood flows into the machine at high
• Why does dialysis use a counter current system?

  •To ensure there is a diffusion gradient for urea
• Why is anti coagulant used in a dialysis machine?

  •Prevent clotting.
• How does dialysis prevent losing glucose?

  •The dialysis fluid contains the same amount of glucose as the blood to ensure that diffusion of glucose doesn't occur
• What is a long term solution to kidney failure?

  •Transplant at least one kidney
• What do patients have to take after a kidney transplant?

  •Immunosuppressant drugs to ensure they don't reject the kidney
• What is the benefit of having a kidney transplant as opposed to dialysis?

  •Patients are able to resume their normal life
• What is the dialysis fluid made of?

  •Glucose, ions and water
• Why is the dialysis fluid constantly kept flowing?

  •so it can be replaced with a fresh solution
• What is a nephron

  •Functional unit of the kidney where filtration and selective reabsorption takes place
• if blood levals become to high the kidney produces more what

  Dilute urine