Week 3 - Renal Blood Flow Flashcards
What supplies the kidneys with blood?
Renal artery
What is the blood supply of the kidneys starting with renal artery?
Renal artery Segmental artery Interlobar artery Arcutate artery Interlobular artery - gives rise to afferent arteriole
What arterioles bring blood to and from glomerulus?
Afferent brings blood to and efferent brings blood away
What is vasa recta?
Type of peritubular capillary only found in nephrons
Forms 2 parallel looks around loop of henle
What is the difference between cortical and juxtamedullary nephrons?
Juxtamedullary have much longer loops of henle and have vasa recta
The afferent arterioles in cortical nephrons has a wider diameter than the efferent arterioles, they are similar diameters in juxtamedullary nephrons
How much blood is filtered at one time?
20%
Where is the glomerulus found?
Cortex
What is different about the non filtered blood?
Increased haematocrit as some plasma removed
Increased concentration of albumin
Increased oncotic potential
What is filtered at the glomerulus?
Water, salts and small molecules pass through
Cells and large proteins dont
What are the three layers of the filtration barrier?
Capillary endothelium, basement membrane, podocyte layer
What does the capillary endothelium filter?
Water, salts and glucose move between cells
What does the basement membrane filter?
Permeable to small proteins
Made of negatively charged glycoproteins that repel protein movement as they are negative
What does the podocyte layer do?
Forms filtration slits
Albumin and blood cells cant fit
What problem may occur to the podocyte layer?
May block or break and let everything through causing blood and proteins to be found in the urine
What is proteinuria and what is it caused by?
Protein is found in urine
In many disease processes the negative charge on filtration barrier is lost so proteins are more readily filtered
What are the forces involved in plasma filtration?
Hydrostatic pressure in capillary
Hydrostatic pressure in bowman’s capsule
Oncotic pressure difference between capillary and tubular lumen
Why is the hydrostatic pressure in the capillary so high?
Afferent arteriole is larger in diameter than efferent arteriole
This means more blood flows in than out therefore increasing the pressure
What are the 2 types of autoregulation?
Myogenic response
Tubular glomerular feedback
What affect would increased afferent resistance have on filtration?
Reduce
What effect would decreased afferent resistance have on filtration?
Increase
What effect would increasing efferent resistance have on filtration?
Increase
What would the myogenic response be to increased blood pressure?
Afferent arteriole constriction
What would the myogenic response be to a decrease in blood pressure?
Afferent arteriole dilatation
What are the limits of blood pressure that autoregulation can control?
80-180 mmHg
