Renal 2.3: The rest of the ions

Question 1

True or False,

Majority of potassium unlike sodium will be extreted out

Answer 1

False,

Majority is re-absorbed just like sodium (majority in tubule proximale)

Question 2

Where is potassium re-absorbed?

Answer 2

plupart réabsorbé passivement au niveau du tubule proximal
activement réabsorbé dans la branche ascendante large de l’anse de Henle (NaK2Cl)

Question 3

True or False

A key region for K+ re-absorption is in the tube colelcteur

Answer 3

FALSE

This is where you have K+ secretion for fine tuning
You use the electric gradient generated by the Na+ to excrete a K+

Question 4

What does the Regulation de la distribution du potassium intra et extra cellulaire?

Answer 4

Na+ K+ pump

Question 5

A patient who underwent cardiac surgery has an increased level of catecholamines. What is the danger of this?

Answer 5

Catecholamines stimulate NaK-ATPase
By default it pumps K+ in the cells
By hyperactivating it you reduce number of K+ in the blood

Question 6

You have a diabetic patient who often feels lightheaded. What do you excpect to see in their ion tests?

Answer 6

Decreased levels of K+ in the plasma
Insuline is a stimulator of NaK-ATPase

Question 7

What is the effect of exercisie in potassium?

Answer 7

When you exercise, your muscles lose potassium, which leads to a significant increase in blood potassium levels

Question 8

What is the hormone that stimulates and one that would inhibit K+ secretion?

Answer 8

First of all, it happens in the tubule collecteur
It uses the gradient created by the movement of Na+
As such, it is the parallal of what stimulates or inhibits the ENaC:

Inhibit secretion of K+ -> ANP, Prostaglandins
Stimulate Secterion of K+ -> aldosterone, ADH

Question 9

If a patient is prescried a dieretic that works on the anse de henle, what are the effects on the plasma potassium levels?

Answer 9

diurétiques agissant avant le tubule collecteur inhibent la réabsorption de sodium

this means that there will be more sodium in the tubule collecteur -> more sodium reabsorption at this point and thus MORE K+ SECRETION

Question 10

If you have a patient with high sodium in blood but low potassium. What do you need to prescribe?

This is part one of the question

Answer 10

First of all, obviosly a diuretic -> reduce reabsorption of sodium
now, because they have low potassium, the dieretic needs to target tube collecteur so something like a prostaglandine

(bcz if you block easrly then you will excrete more K+)

Question 11

If you have a patient with high sodium in blood but low potassium. What do you need to prescribe if they are allergic to prostaglandins?

Answer 11

antagonistes de l’aldostérone

Question 12

True or False,

A patient will never have bicarbonate HCO3- in the urine

Answer 12

TRUE

BICARBONATE ALWAYS ALL REABSORBED

only times when you will havee HCO3- is when we have a large concentration of it in the blood

Question 13

Exam question**

What are Inhibiteurs de l’anhydrase carbonique?

Answer 13

Diuretics that act on Tube proximal

Diuretics reduce sodium re-absorption

Question 14

Where does bicarbonate re-absorption occur?

Answer 14

Tube proximal

Question 15

What type of diuretic would lead in an acidosis?

Answer 15

Because HCO3- is reabsorbed at the tube proximal, then diuretics taht block sodium reabsorption here will block HCO3- reabsorption

One example is: Inhibiteurs de l’anhydrase carbonique

Question 16

Describe bicarbonate reabsorption mechanism?

Answer 16

Bicarbonate Conversion: Bicarbonate absorption by the proximal tubule is dependent on the activity of an enzyme called** carbonic anhydrase** (CA). This enzyme converts bicarbonate (HCO3-) to CO2 and H2O.

CO2 Diffusion: The CO2 produced rapidly diffuses across the cell membrane of proximal tubule cells. Once inside the cells, CO2 is rehydrated back to H2CO3 by carbonic anhydrase.

Here, HCO3- can go into blood flow and the proton generated can be used by the antiporter to pump a Na+ ion in. And the cycle re-begins. H+ finds bicarbonate, CA creates C02 H20, in the cell we get one proton and one HCO3- that goes in the blood and repeat