Lecture 51 – Glomerular filtration and renal clearance

Question 1

Medulla of kidney

Answer 1

Loops of Henle, collecting tubules and ducts, vasa recta

Question 1

Cortex of kidney

Answer 1

Glomeruli, PCTs and DCTs vessels

Question 2

Amount of solute excreted equation

Answer 2

= amount filtered – amount reabsorbed + amount secreted

Question 3

Plasma volume moving along nephron

Answer 3

o Plasma volume entering afferent arteriole = 100%
o 20% of volume filters
o >19% of fluid is reabsorbed
o >99% of plasma entering kidney returns to systemic circulation
o >1% of volume is excreted to external environment

Question 4

What is renal clearance?

Answer 4

Clearance is defined as the rate of urinary excretion of a substance, relative to its plasma concentration

Question 5

Autoregulation for GFR

Answer 5

Maintains nearly constant GFR when mean arterial BP is between 80- and 180-mm Hg

Question 6

Stabilising GFR

Answer 6

o Autoregulation
o Myogenic response
o Tubuloglomerular feedback

Question 7

GFR through nephron

Answer 7

o GFR increases as fluid exits bowman’s capsule
o Flow through tubule increases
o Flow past macula densa increases
o Paracrine diffuses from macula densa to afferent arteriole
o Afferent arteriole constricts
o Resistance in afferent arteriole increases
o Hydrostatic pressure in glomerulus decreases
o GFR decreases

Question 8

Renin-angiotensin-aldosterone system

Answer 8

o Angiotensin II
o Angiotensin II
o Aldosterone

Question 9

Sympathetic nervous system

Answer 9

Noradrenaline

Question 10

ANP

Answer 10

Atrial natriuretic peptide