GFR + Filtration Flashcards
What are the 2 types of nephron?
Cortical nephron
Juxtamedullary nephron
Where are cortical nephrons found?
Outer part of cortex
Where are juxtamedullary nephrons found?
Inner part of cortex - next to medulla
Which nephron has a longer loop of Henle?
Juxtamedullary
What does the efferent arteriole go to form in a cortical nephron?
Peritubular capillary
What does the afferent arteriole go to form in a juxtamedullary nephron?
Vasa recta
Which nephron type are there more of?
Cortical
What percentage of blood at glomerulus is filtered?
20%
What is does the glomerulus filter out?
Keeps large proteins and cells in blood
What size do molcules have to be to be filtered by glomerulus?
<1.48nm
What charge is the glomerulus more permeable to?
Positive
What happens to the afferent arteriole if BP increases?
Constricts
What happens to the afferent arteriole if BP decreases?
Dilates
What is tubuloglomerular feedback?
Mechanism that links NaCl concentration at the macula densa with control of renal arteriolar resistance
What are the 2 components of tubuloglomerular feedback?
Afferent arteriole resistance
Efferent arteriolar feedback
What does tubuloglomerular feedback control?
Distal solute deliver - so tubular reabsorption
Where are macular densa cells found?
DCT
What is the tubuloglomerular feedback response if NaCl increases?
GFR needs to decrease
Adenosine released
- vasoconstriction of AA via A1 receptors
- vasodilation of EA via A2 receptors
Reduces pressure gradient across glomerulus
Slows GFR
How do A1 receptors work?
Increase concentration of intracellular calcium
What is the tubuloglomerular feedback response if NaCl decreases?
GFR needs to increase
Prostagland release - causes vasodilation of AA
What autonomic fibres innervate the AA + EA?
Sympathetic fibres
