Tubular Disorders ✅ Flashcards
How much plasma does the adult kidney filter per day on average?
150L of plasma
How much sodium does the adult kidney filter per day on average?
22.5mmol
What % of filtered sodium is reabsorbed by the tubules?
99%
What do disorders in sodium handling affect?
BP
What effect does sodium-losing disorders have on BP?
Hypotension
What effect to sodium-retaining disorders have on BP?
Hypertension
What transporter is important in sodium homeostasis?
Na/K-ATPase
What cells is Na-K-ATPase present in?
All cells
What is the importance of Na/K-ATPase?
It is the driving force which generates a favourable eletrochemical gradient for Na entry into the cell
What does the sodium gradient allow?
Co-transport of other substances, such as glucose, amino acids, phosphate
What happens to fractional excretion of sodium in renal salt-wasting disorders?
It is almost always normal
Why is fractional excretion of sodium normal in almost all renal salt-wasting disorders?
Because sodium is the main determinant of intravascular volume, so in salt-wasting disorders there is activation of RAAS
What are the functions of the proximal tubule?
- Glucose transport
- Phosphate transport
- Amino acid transport
What renal tubular disorders affect the proximal tubule?
- Renal glycosuria
- Hypophosphataemic rickets
- Isolated, generalised aminoaciduria
What is generalised dysfunction of the proximal tubule called?
Fanconi syndrome
What is the function of the ascending limb of Henle?
Sodium, potassium, and chloride transport
What renal tubular disorder affects the ascending limb of Henle?
Bartter syndrome
What are the functions of the distal tubule?
- Proton (H+) secretion
- Sodium chloride transport
What renal tubular disorders affect the distal tubule?
Distal renal tubular acidosis
Gitelman syndrome
What are the functions of the collecting duct?
- Water transport
- Sodium and potassium transport
What renal tubular disorders affect the collecting duct?
- Nephrogenic diabetes insipdius
- Pseudohypoaldosteronism
- Liddle syndrome
What is Fanconi syndrome?
A generalised proximal tubular disorder
What happens to glomerular function in Fanconi syndrome?
It is at least initially well preserved
What can the causes of Fanconi syndrome be divided into?
- Congenital
- Acquired
- Renal