Into to the Kidney

Question 1

Briefly explain the functions of the kidney

Answer 1

• Control of solutes and fluids,
• Blood pressure control,
• Acid base control
• Metabolic waste excretion,
• Endocrine functions,
• Drug metabolism/excretion

Question 2

What is reabsorbed at different parts of the kidney tubule?

Answer 2

1. PCT reabsorbs water, ions (via SGLT) and removes toxins.
2. Descending loop of Henle reabsorbs water via aquaporin
3. Ascending loop of Henle reabsorbs sodium and chloride
4. Distal tubule secretes and absorbs ions to maintain pH
5. Collecting ducts reabsorbs water, this is where ADH acts

Question 3

What is measured in Urea and Electrolytes panel?

Answer 3

• Sodium,
• Potassium,
• Chloride,
• Urea,
• Creatinine,
• eGFR

Question 4

What is creatinine affected by?

Answer 4

• Amount of muscle bulk,
• Plasma volume,
• Diet

Question 5

What is urea affected by?

Answer 5

• Diet high in protein or GI bleed will increase urea,
• Dehydration will increase urea,
• Tissue breakdown will increase urea,
• Liver failure will lower urea

Question 6

What is the glomerular filtration rate?

Answer 6

• Volume of plasma cleared of a substance per unit time (ml/min).

Question 7

What is the best measure of GFR?

Answer 7

Inulin however not routinely done

Question 8

What is the issues with eGFR?

Answer 8

• It is less accurate at high GFR.
• It assumes stable renal function,
• It is not suitable in AKI