Ion transport Flashcards
(blank) only occurs from the glomerulus into the bowman’s space.
filtration
(blank) is when substance moves from tubule into peritubular capillaries
Reabsorption
(blank) is the movement of substance from the peritubular capillaries into the tubule
secretion
(blank) is the movement of substance into the urine
excretion
(blank) is the travel through the tight junctions of the cells.
(blank) is the travel through the cell
Paracellular
Transcellular
What are the three kind of active transport?
Primary-> carrier transport (H+ATPase)
Secondary (coupled transport)-> symport (Na+/Cl-) and antiport (Na+/H+)
What are the two types of passive transport?
Simple diffusion (Ca2+) and facilitated diffusion (urea) (uniport)
The (blank) provides the energy for Na to move- which allows other molecules to move with or against Na (symport/anitport)
Na/K ATPase
Movement of Na is down an (blank) gradient. Na allows for secondary transport.
electrical chemical
In the lumen of the proximal tubule Na allows for what?
allows for symport with glucose, AA and others out of the proximal tubule, and allows for antiport with H+ allowing hydrogen to enter the tubule
Potassium reabsorbed too
Also Water reabsorption and reabsorption of HCO3
In the thick ascending loop of henle what does sodium allow for?
reabsorption of
Na Cl, K via Symport co transporter
In the distal convoluted tubule what does sodium allow for?
Cl-, Ca, water to leave the lumen of the distal tubule and for Potassium to enter it.
What does sodium allow for in the collecting duct?
just itself to leave the collecting duct
Potassium may be reabsorbed (H, K atpase) or secreted (Na K Atpase) depending on body needs
Where does the majority of reabsorption of Na+ happen? Does the amount of reabsorption increase or decrease and you move down through the nephron?
in the proximal tubule (67%)
There is less reabsorption as you go down through the nephron
How does water flow throughout the nephron?
it follows the sodium
Almost all Na+ is (blank). How do you know if you are dehydrated?
reabsorbed!! (i.e almost none is excreted
If there is NONE at ALL sodium excreted
Movement of Cl- into cells is (blank) an electrochemical gradient.
Up
Movement of Na into cells is (blank) an electrochemical gradient.
down
How can Cl- get into the peritubular lumen?
symport with potassium
Does Cl- transport in or our of the collecting duct?
It doesnt do anything in the collecting duct
When does Cl leave the lumen of the nephron?
When does Cl enter the peritubular capillaries
- In the proximal tubule, thick ascending loop of henle, distal convoluted tubule
- In the proximal tubule, thick ascending loop of henle, distal convoluted tubule
What kind of transport do chloride ions use in the proximal tubule?
Passive transport (more than 50%) of the time due to Na+ and Water resorption messing with the gradient and sometimes via secondary transport
In the proximal tubule Na+ reabsorption increases so what happens next?
Water reabsorption and increased luminal Cl- Concentration and increased Urea concentrion which gives the lumen a more negative potential which allows for passive Cl- reabsorption and passive urea reabsorption
at one on a TF/P by %proximal tubule length graph denotes what?
the concentration of these substrates in the tubular fluid is the same as it is in the plasma
Na is a (blank) process
isosmotic process
What does the clearance rate of inulin tell you?
gives you the GFR
Explain how the TF/P by %proximal tubule length graph works.
as you move along the proximal tubule you are having water reabsorbed at a certain rate. Therefore if substances are getting reabsorbed at the same rate (like Na) then they be equally concentrated throughout the tube. However if substances aren’t getting reabsorbed at the same rate, then the water will leave the tube and the substance will therefore be more concentrated and as such their line will be very steep and positive. If substances are getting reabsorbed faster than water than their line will b negative
According to the TF/P by %proximal tubule length graph, what get reabsorbed quickly?
Slowly?
As fast as water?
Glucose, AA, HCO3-
PAH, Inulin, Cl-
K+, Na+
When you put in a certain amount of potassium you need to get out that same amount. This is called (blank)
potassium homeostasis
What potassium level do you want to maintain?
4.2
(blank) percent of total body potassium is intracellular.
98%
Hyperosmolarity, exercise and cell lysis makes potassium do what?
leave the ICF (increases intracellular dehydration)
Insulin, B-agonists, aldosterone, and alkalosis makes potassium do what?
makes potassium move into the cellular fluid
Insulin stimulates K uptake after meal indirectly by increasing Na entry via (blank) which enhances Na/K pump. Otherwise hyperkalemia could cause neurological problems.
Na/H exchange
How does alkalosis affect intracellular potassium?
Alkalosis- movement of H and K (reciprocal)- less H+ tend to have H+ shift out of cells and K into cells (net movement of K+ into cells during alkalosis)
How does epinephrine increase Intracellular concentration of potassium?
Epinephrine stimulates K uptake by stimulating Na/K ATPase.
How does exercise decrease intracellular potassium?
During exercise- you have a large amount of action potential- tend to get extra K moving out of cells- the sympathetic response and the release of epi stimulates the Na-K pump helping to put K back into cells.
K+ moves via (blank) (passive) in the PCT (most of it does).
paracellular transport
When potassium moves from the PCT transcellularly what does it utilize?
ATP
When potassium moves from the PCT paracellularly, how does it move?
passively
When potassium moves from the PCT transcellularly via ATP how does it get out into the peritubular fluid?
passively
When potassium moves out of the peritubular lumen how does it do it?
via Na/K exchanger
Potassium handling in the late distal tubule and collecting ducts includes potassium secretion by (blank).
principal cells
What are the majority of the cells in the distal tubule and collecting ducts?
65% principal cell and 35% intercalated cells
When Na goes into the distal tubule surrounding cells what happens to K secretions?
the potassium secretion increase into the peritubular fluid due to enhancement of principal secretion
Where in the nephron do you get rid of potassium (i.e reabsorption occurs)?
the distal tubule and the collecting , thick ascending loop of henle, proximal convoluted tubule
What is the normal fractional excretion of potassium?
10-20%
What are 2 factors affecting potassium secretion?
1) intracellular potassium
2) aldosterone
(blank) increase the conduction of Na which increaeses the secretion of K+ into the tubule
aldosterone
You can think of potassim and sodium as having what kind of relationship (except in thick ascending loop of henle ?
an inverse one (when one comes in the other goes out)
What is the charge in the tubular lumen?
negative
Where does potassium enter the nephron?
DCT
An increase in (blank) stimulates the adrenal gland to release of aldosterone- which enhances the secretion of K+ into the tubule and out into the urine
K+
it does this to try and rid your plasma of the excess potassium
How many grams of KCl are excreted per day?
5 grams
What is the equation for filtered load?
GFR X Px=mg/min
What is the fractional excretion of K+?
72mEq/day
about 10% of filtered load
(blank) are diuretic drugs that do not promote the secretion of potassium into the urine
(blank) are diuretic drugs that DO promote the secretion of potassium into the urine.
potassium sparing diruetics
potassium losing diruetics.
What are the potassium losing diuretics?
furosemide
thiazide
What are the potassium sparing diuretics?
amiloride
(blank) acts by inhibiting NKCC2, the luminal Na-K-2Cl symporter in the thick ascending limb of the loop of Henle.
Furosemid
(blank) inhibits the NaCl symport in the distal covoluted tubule
Thiazide
(blank) inhibits Na reabsorption in the late distal convoluted tubules, connecting tubules, and collecting ducts in the kidneys.
amiloride
When using furosemide what results in the urine?
increase flow, increased NaCl, Increase K+
When using amiloride what results in the urine?
increase flow, increased NaCl, lower amount of K+
What drug increases Na outflow and therefore increases K inflow?
furosemide
What dug decreases Na outlflow and therefore decreases K in flow?
amiloride
What are these:
Bartters syndrome (type I)
Gitelmans syndrome
Liddle syndrom
disorders of distal nephron
What disease results due to a mutation of Na/K/Cl transporter in thick ascending limb?
bartters syndrome
What disease results due to mutation of Na/Cl transporter in distal tubule?
Gitelmans syndrome
What disease results due to increased number and open time of principal sodium channels?
Liddle’s syndrome
Which disease results in:
Low potassium levels, alkalosis, polydipsia, poluria, normal to low blood pressure
bartters syndrome and Gitelman’s syndrome
What disease results in:
Low potassium levels, alkalosis ,hypertension
liddles syndrome
What drug can cause resemblance to bartters syndrome?
ferosimide
What drug can cause resemblance to Gitelmans syndrome?
Thiazide
What drug can cause resemblance to Liddles syndrome?
aldosterone
(blank) is described when drinking lots of water
polydipsia
