Tubule system = Bowman’s capsule, loop of Henley, (would do nothing w/o vascular
system need to have exchange b/w the two system to do process of urine production)
Vascular network can be seen in series of diff vessels,
Renal artery brings blood into afferent arteriole (leads to individual Glomerulus)
Glomerulus is just a cluster of capillaries.
Efferent arterioles feed next type
Peritubular are the capillaries are the capuillaries wrapped around loop of Henley of the
majority of the nephrons,
Vesa Recta are referring to the specific capillaries wrapped around loop of Henely
(deepest of nephrons) that go down into the medulla .
Leads into venules, empty into renal vein to take things away
Arterioles= vasoconstriction and vasodilation
Kidney= fluid exchange
Two major areas exchange b/w
(Peritbular OR Vesa Recta) ** very important to reclaim that vol which was
filtered in glomerulus , things which got filtered will be reabsorbed back into the
Diagram on the right is simple illustration of the nephron
1. Kidenys recive 20% of Cardiac Output ,
Cardiac output 5l/Min .. how much plasma enters the kidney per day
5/L min * 60min/hour * 24 hours /day =7200L/Day (amount of blood heart is pumping in
a day at resting cardiac output) -Kidney is 20%
7200* .20 = 1440 L/min ( big portion of blood cannot be filtered , how much of this
volume is just plasma)
3L outta the 5L is plasma, that’s 60% so that means 1440 * 0.60 =840 plasma
20% of plasma is filtered
840* 0.20 =168
168 is going to be filtered that crosses from the plasma, and into Bowman space and
Once plasma crosses out the Glomerulus and into the tubule it is referred to as
20% crosses out of the glomerulus and into the tubule to BECOME FILTERATED.
80% continues its way out to efferent arterioles and into pertubular tubules.
Reducing the amount which is filtered, when you have kidney damage, toxicity builds in
the blood and could be harmful.
If 120ml of plasma are filtered each minute, and the filteration fraction is 20%? What is
the daily renal plasma flow?
120ml//min * 60 min/hour * 24 hr/day =172,800ml per day is filtered
172.8 L/day which represents 20% of total renal plasma flow
172.8 / .20 = 864 L /day
Three Critical Functions of the nephron:
1. The starting off point (Glomerular filteration process) . Non discriminant filteration
means that any plasma components that can fit through filteration slits, is going to move
through. Bulk flow process. 20% of everything is going which is right size. That creates
filterate and once that filterate is in the tubule, we want to be more selective
2. Tubular Reabsorption: Move substances from the filtrate across the wall of the tubule, across the interstitial fluid and into per tubular capillary
3. Tubular secretion: unique process within the kidney, this is movement of substances
from the peritubular capillaries, across interisital fluid , and into the tubular filterate.
VERY SELECTIVE—only going to apply to certain molecules subjected to the
secretion. Another way kidney adds substance to the filterate.
How substance is being handled?
Amount filtered – Amount reabsorbed + Amount secreted = Amount of Solute excreted
F R S E
Not all substances handled equally!
4 examples, looking at particular substances dissolved in plasma (dots )
1.Filteration: The amount of the substance that was filtered (20%). This is a process
that occurs across the board. Similar thing happens in each of the other examples.
(Stuff gets filtered but nothing happens not reabsorbed or excreted )
(what u filter = what u will get in urine
Example: No Reabsorption