L18: Potassium And More Flashcards
Where does most of the potassium exist
Intracellular
What would happen to the potassium if we add more potassium into the extracellular spade
Potassium will move to the intracellular space
What occurs when there is high potassium potassium
Hyperkalaemia
What are the causes of hyperkalaemia
End stage renal failure Crush injury Blood transfusion Insulin deficiency Over use of potassium sparing diuretics
What is the consequence of hyperkalaemia
Cardiac dysrhythmia
What is the treatment of hyperkalaemia
Restrict potassium diet
Insulin or glucose
How does insulin/glucose cause the decrease of potassium
Insulin stimulates sodium/potassium ATPase so insulin will decrease potassium
Glucose causes the release of insulin
What occurs when there is low level of potassium
Hypokalaemia
What are the causes of hypokalaemia
Diarrhoea
Furosemide (diuretics)
Insulin overdoes
What is the consequence of hypokalaemia
Cardiac dysrhythmia
What is the treatment for hypokalaemia
Give intravenous potassium
Potassium containing food
How is potassium absorbed at the proximal tubule
Absorbed passively and with water paracellular
How is potassium absorbed at the thick ascending limb
Via NKC22 transporter
Where is potassium secreted in the nephron
From Distal tubule to collecting duct
Which cells secrete potassium from distal tubule to collecting duct
Principal cells
Which hormone controls principal cells to secrete potassium
Aldosterone
What is the role of aldosterone
Increase the channel expression
What is the channel of the principal cell called
Apical membrane potassium channel (ROMK)
What other channel at the distal tubule causes the secretion of potassium
Calcium activated potassium channel
Which other part of the nephron is potassium secreted at
Thick ascending limb
Which drugs increase the secretion of potassium
Diuretics such as furosemide
Which main hormone regulates the potassium concentration
Aldosterone
What is the other role of aldosterone in the kidney
Regulate volume
Which are the 2 main points where calcium is reabsorbed in the nephron
Proximal tubule
Thick ascending limb
How does calcium get reabsorbed in the proximal tubule
Moves inside the cell via calcium channels
Moves across the basolateral membrane by calcium ATPase
How is calcium reabsorbed in the thick ascending limb
Absorbed by the positive potential in the lumen
Which hormone does the kidney produce to regulate erythropoiesis in the bone marrow
EPO (erythropoietin)
When is erythropoietin produced
In hypoxia
Where is EPO synthesised
In the renal cortex of mesangial cells
Which transcription factor stimulates EPO production
HIF-2
In what type of disease does EPO levels decrease
Renal failure
What is the treatment for low levels of EPO
EPO analogues
Which hormone is activated in the kidney to stimulate the absorption of calcium and phosphate from the gut
1,25 vitamin D
Where do we get inactive vitamin d from
Sun/skin
Diet
What does activated vitamin D do to the absorption of calcium and phosphate
Increase it
Where is calcium and phosphate absorbed from
The gut
Which hormone is vitamin D under the control of
PTH
Which hormone is involved in the regulation of blood volume that is produced in the kidney
Renin
Therefore what are the 3 hormones the kidney can produce
EPO
Active vitamin D
Renin
Where is calcium reabsorbed in the nephron
Proximal tubule
Thick ascending limb
How is calcium reabsorbed in the proximal tubule
Transcelullar via calcium channel on the apical membrane and calcium ATPase on the basolateral membrane
How is calcium reabsorbed in the thick ascending limb
Due to the reabsorption of water
