Three sets of images show:

1. The far right image shows normal blood flow is being supplied to the the glomerulus
2. Effects of renal hypertension - RAS is a form of hypertension that reduction of blood flow to the afferent arterioles. This stenosis is usually caused by atherosclerosis or fibromuscular dysplasia.
   1. The jutaglomerular apparatus regulates this blood volume. When RAS is present it produces rennin in response to of reduced blood pressure
   2. Rennin is then converted to angiotensin I
   3. Angiotensin I with angiotensin converting enzyme produces angiotensin II
   4. This causes constriction of the efferent arterioles
3. When an ACE inhibitor is applied it prevents the production of ACE conventing enzyme and stops the production of angiotensin II keeping the afferent arteriole dilated
4. Results
   1. This throws off the equalized pressure from both ends of the arterioles resulting in extension of cortical transit and excretion phases of the time activity curve
   2. In severe cases the production of urine becomes static within the tubules and the effected kidney mimics blockage as seen below
   
   3. Example of left renal artery stenosis and how the role of Captopril helps identify RAS