 2.71 Describe the structure of a nephron, to include Bowman’s capsule and glomerulus, convoluted tubules, loop of Henle and collecting duct  2.72 Describe ultrafiltration in the Bowman’s capsule and the composition of the glomerulas filtrate

 Each kidney contains about a million tiny structures called nephrons.  A nephron starts as a cup-shaped Bowman’s capsule which becomes a renal tubule.  Bowman’s capsules are found within the outer cortex region and the renal tubules run from the cortex into the darker medulla.

 Placed end to end, the nephrons of one kidney would stretch about 8km.  A branch of the renal artery supplies the nephrons with blood.  In the Bowman’s capsule, the artery splits up into a network of capillaries called the glomerulus.  These capillaries join up again on leaving the capsule.  The blood vessel splits once more into a second set of capillaries that are wrapped around the renal tubule.

Step 1 Blood flows into the glomerulus from the renal artery. Step 2 High blood pressure in the Glomerulus Forces water, glucose, urea and sats through the capillary wall and into the tubule. Protein molecules and blood cells are too big so they remain in the blood. Step 3 Blood leaves the glomerulus and flows to the capillaries that surround the renal tubule.tubule.

Step 4 The fluid called the glomerular filtrate passes along the tubule. Step 5 All of the glucose and most of the water and salts are absorbed back into the blood in the nearby capillaries – to ensure there’s the right concentration in the blood. Step 6 Urea and other unwanted substances stay dissolved in the glomerular filtrate. They pass down the tubule and eventually reach the bladder.bladder. Step 7 Blood flows out of the kidney to the renal vein.vein.

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